# Meteorology --- ### Q1: What clouds and weather may develop when a humid and unstable air mass is pushed against a mountain chain by the prevailing wind and forced upward? ^t50q1 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q1) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q1) - A) Overcast low stratus (high fog) with no precipitation. - B) Thin Altostratus and Cirrostratus clouds with light and steady precipitation. - C) Embedded CB with thunderstorms and showers of hail and/or rain. - D) Smooth, unstructured NS cloud with light drizzle or snow (during winter). #### Answer C) #### Explanation When unstable, humid air is forced to rise orographically, it triggers convective instability — air that is conditionally unstable becomes absolutely unstable once lifting begins. The resulting rapid ascent fuels cumulonimbus development, producing embedded CBs with thunderstorms, heavy showers, and hail. Stable air masses under the same conditions produce layered clouds (Ns or As) with steady rain, not convective storms. #### Key Terms CB = Cumulonimbus (thunderstorm cloud) #### Source - [?] Source non identifiée ### Q2: What type of fog forms when humid and nearly saturated air is forced to rise along the slopes of hills or shallow mountains by the prevailing wind? ^t50q2 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q2) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q2) - A) Radiation fog - B) Steaming fog - C) Advection fog - D) Orographic fog #### Answer D) #### Explanation Orographic fog forms when wind-driven humid air is mechanically lifted along a slope, cooling adiabatically until it reaches the dew point. Radiation fog requires calm nights with radiative ground cooling, advection fog forms when warm moist air moves over a cold surface, and steaming fog (Arctic sea smoke) occurs when cold air passes over warm water — none of these involve slope-forced lifting. #### Source - [S3 Q12 p.25](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=25) (score: 0.21) - [QuizVDS Q2](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q2): Answer D ### Q3: What phenomenon is known as "blue thermals"? ^t50q3 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q3) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q3) - **A)** Turbulence in the vicinity of Cumulonimbus clouds - **B)** Descending air between Cumulus clouds - **C)** Thermals without formation of Cu clouds - **D)** Thermals with less than 4/8 Cu coverage #### Answer C) #### Explanation "Blue thermals" exist when the lifting condensation level (LCL) is very high — the air is too dry to reach its dew point before the thermal tops out. As a result, thermals rise but no cumulus clouds form, leaving the sky clear ("blue"). For glider pilots this is challenging since there are no visual cloud markers to indicate thermal location, and the cloudbase is beyond the thermal ceiling. #### Source - [?] Source non identifiée ### Q4: The expression "beginning of thermals" refers to the moment when thermal intensity ^t50q4 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q4) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q4) - **A)** Becomes usable for cross-country gliding by formation of Cu clouds. - **B)** Becomes usable for gliding and reaches up to 600 m AGL. - **C)** Reaches up to 600 m AGL and forms Cumulus clouds. - **D)** Becomes usable for gliding and reaches up to 1200 m MSL. #### Answer B) #### Explanation Thermal activity is considered to have "begun" when thermals are strong enough to support gliding and extend to at least 600 m AGL — sufficient altitude to work the lift. Below this height, thermals may exist but are too shallow to be safely exploited by a glider. Cloud formation is not a prerequisite; blue thermals (see Q3) can also mark the beginning of usable thermal activity. #### Key Terms - **AGL** = Above Ground Level - **MSL** = Mean Sea Level #### Source - [?] Source non identifiée ### Q5: The "trigger temperature" is the temperature that ^t50q5 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q5) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q5) - A) Must be obtained at ground level so Cumulus clouds can be formed by thermal lifts. - B) Is reached by a thermal lift during ascent when Cumulus cloud formation begins. - C) Is the minimum temperature at ground level required for thunderstorm development from a Cumulus cloud. - D) Is the maximum temperature at ground level that can be reached without thunderstorm formation from a Cumulus cloud. #### Answer A) #### Explanation The trigger temperature is the minimum surface temperature that must be reached before thermals can rise to the condensation level and form cumulus clouds. It is derived from the aerological diagram (tephigram/Stüve diagram) by tracing the dry adiabatic lapse rate from the morning sounding's moisture level back to the surface. Until this temperature is reached, thermals may exist but will not produce cumulus markers. #### Source - [?] Source non identifiée ### Q6: What is meant by "over-development" in a weather report? ^t50q6 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q6) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q6) - **A)** Development of a thermal low to a storm depression - **B)** Widespreading of Cumulus clouds below an inversion layer - **C)** Change from blue thermals to cloudy thermals during the afternoon - **D)** Vertical development of Cumulus clouds to rain showers #### Answer D) #### Explanation Over-development occurs when cumulus clouds continue growing vertically beyond the thermal inversion or become self-sustaining through latent heat release, developing into cumulonimbus (Cb) with heavy rain showers, lightning, and hail. This typically happens during humid summer afternoons when atmospheric instability is high and the inhibiting layer is weak. For glider pilots, over-development signals the end of safe soaring conditions and a need to land. #### Source - [?] Source non identifiée ### Q7: The gliding weather report indicates environmental instability. Morning dew is present on the grass and no thermals are currently active. What thermal development can be expected? ^t50q7 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q7) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q7) - **A)** Environmental instability prevents air from being lifted and no thermals will form - **B)** After sunset and formation of a ground-level inversion, thermal activity is likely to start - **C)** With ongoing insolation and ground warming, thermal lifting is likely to begin - **D)** Formation of dew prevents all thermal activity for the day #### Answer C) #### Explanation Morning dew indicates the air cooled to the dew point overnight (radiation cooling), but this is temporary. Once solar insolation heats the ground, the surface temperature rises, warming the air above it until the temperature exceeds the trigger temperature. Environmental instability means the lapse rate is steep enough to sustain thermals once they begin, so good thermal conditions are likely to develop during the morning hours. #### Source - [?] Source non identifiée ### Q8: What effect on thermal activity can be expected when cirrus clouds approach from one direction and become increasingly dense, blocking the sun? ^t50q8 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q8) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q8) - **A)** Cirrus clouds indicate instability and the onset of over-development - **B)** Cirrus clouds may intensify insolation and improve thermal activity - **C)** Cirrus clouds prevent insolation and impair thermal activity. - **D)** Cirrus clouds indicate a high-level inversion with ongoing thermal activity up to that level #### Answer C) #### Explanation Thermals are driven by differential heating of the ground by solar radiation. Thickening cirrus clouds progressively filter out solar energy, reducing ground heating and therefore thermal strength and depth. Dense cirrus can reduce insolation enough to stop thermal activity entirely. Additionally, approaching cirrus from one direction often indicates an advancing warm front, which brings widespread cloud, stable conditions, and further suppression of thermals. #### Source - [?] Source non identifiée ### Q9: What situation is known as "shielding"? ^t50q9 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q9) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q9) - **A)** Coverage of Cumulus clouds, stated as part of eighths of the sky - **B)** Anvil-like structure at the upper levels of a thunderstorm cloud - **C)** Ns clouds covering the windward side of a mountain range - **D)** High or mid-level cloud layers impairing thermal activity #### Answer D) #### Explanation Shielding describes the effect of high or medium cloud layers (cirrus, cirrostratus, altostratus) that block solar radiation and suppress thermal development below. Even partial cloud cover at these levels can significantly reduce ground insolation. Gliding forecasts include shielding assessments to indicate when and where thermals will be weakened or absent due to cloud cover above the expected thermal layer. #### Source - [?] Source non identifiée ### Q10: While planning a 500 km triangle flight, there is a squall line 100 km west of the departure airfield, extending north to south and moving east. What would be a sensible decision regarding the weather? ^t50q10 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q10) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q10) - **A)** Plan the flight below the thunderstorm cloud bases - **B)** Change plans and start the triangle heading east - **C)** Postpone the flight to another day - **D)** During flight, look for gaps between thunderstorms #### Answer C) #### Explanation A squall line is an organized line of severe thunderstorms that is notoriously fast-moving, unpredictable, and extremely dangerous. Moving at typical speeds of 30–60 km/h, a squall line 100 km away could reach the airfield within 2–3 hours. Flying below Cb cloud bases or attempting to navigate between cells exposes the glider to extreme turbulence, windshear, hail, and downdrafts. The only safe option is to not fly until the hazard has completely passed. #### Source - [?] Source non identifiée ### Q11: What is the gas composition of "air"? ^t50q11 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q11) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q11) - **A)** Nitrogen 21 % Oxygen 78 % Noble gases / carbon dioxide 1 % - **B)** Oxygen 21 % Water vapour 78 % Noble gases / carbon dioxide 1 % - **C)** Oxygen 78 % Water vapour 21 % Nitrogen 1 % - **D)** Oxygen 21 % Nitrogen 78 % Noble gases / carbon dioxide 1 % #### Answer D) #### Explanation Dry air by volume is approximately 78% nitrogen (N2), 21% oxygen (O2), and the remaining 1% consists of argon, carbon dioxide, and other trace gases. Water vapour is variable (0–4%) and is not counted in the standard dry-air composition. Knowing air composition is fundamental to understanding atmospheric physics, density calculations, and the behaviour of aircraft engines and instruments. #### Source - [VV Q8 p.108](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=108) (score: 0.44) - [QuizVDS Q11](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q11): Answer B - PDF Answer: D ### Q12: In which atmospheric layer are weather phenomena predominantly found? ^t50q12 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q12) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q12) - **A)** Stratosphere - **B)** Troposphere - **C)** Thermosphere - **D)** Tropopause #### Answer B) #### Explanation The troposphere extends from the surface to approximately 8–16 km depending on latitude and season. It contains approximately 75–80% of the atmosphere's total mass and almost all its water vapour. Convection, cloud formation, precipitation, fronts, and wind phenomena all occur here because temperature decreases with height, driving convective instability. Above the tropopause, the stratosphere is stable and largely cloud-free. #### Source - [VV Q6 p.108](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=108) (score: 0.22) - [QuizVDS Q12](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q12): Answer D - PDF Answer: B ### Q13: What is the mass of a "cube of air" with 1 m edges at MSL according to ISA? ^t50q13 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q13) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q13) - **A)** 12.25 kg - **B)** 0.01225 kg - **C)** 1.225 kg - **D)** 0.1225 kg #### Answer C) #### Explanation According to the International Standard Atmosphere (ISA), air density at mean sea level is 1.225 kg/m³. Therefore a 1 m³ cube of air has a mass of 1.225 kg. This density value is fundamental to aviation: it affects lift, drag, engine power, and altimeter calibration. Density decreases with altitude and increases temperature/humidity changes also affect it, which is why density altitude matters for aircraft performance. #### Key Terms - **ISA** = International Standard Atmosphere - **MSL** = Mean Sea Level #### Source - [?] Source non identifiée ### Q14: At what rate does the temperature change with increasing altitude according to ISA within the troposphere? ^t50q14 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q14) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q14) - A) Increases by 2° C / 1000 ft - B) Decreases by 2° C / 100 m - C) Decreases by 2° C / 1000 ft - D) Increases by 2° C / 100 m #### Answer C) #### Explanation The ISA standard lapse rate is 1.98°C per 1000 ft (approximately 2°C/1000 ft), or 6.5°C per 1000 m. This is the Environmental Lapse Rate (ELR) used as a reference for altimeter calibration and pressure calculations. The actual ELR varies with weather conditions — steeper than ISA indicates instability and favours thermals, shallower or negative (inversion) indicates stability and suppresses convection. #### Key Terms ISA = International Standard Atmosphere #### Source - [VV Q30 p.113](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=113) (score: 0.28) - [QuizVDS Q14](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q14): Answer A - PDF Answer: D ### Q15: What is the mean tropopause height according to the ISA (ICAO Standard Atmosphere)? ^t50q15 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q15) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q15) - A) 36000 m - B) 11000 ft - C) 18000 ft - D) 11000 m #### Answer D) #### Explanation The ISA tropopause is defined at 11,000 m (approximately 36,089 ft), where the temperature reaches -56.5°C and then remains constant with height into the lower stratosphere. In reality the tropopause height varies: it is lower over the poles (~8 km) and higher over the tropics (~16 km), and fluctuates with season and synoptic weather patterns. Cumulonimbus tops that penetrate the tropopause are especially violent. #### Key Terms - **ISA** = International Standard Atmosphere - **ICAO** = International Civil Aviation Organization #### Source - [VV Q7 p.108](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=108) (score: 0.23) - [QuizVDS Q15](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q15): Answer B - PDF Answer: D ### Q16: The "tropopause" is defined as ^t50q16 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q16) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q16) - A) The boundary area between the mesosphere and the stratosphere. - B) The boundary area between the troposphere and the stratosphere. - C) The height above which the temperature starts to decrease. - D) The layer above the troposphere showing an increasing temperature. #### Answer B) #### Explanation The tropopause is the transition boundary between the troposphere (where temperature decreases with height) and the stratosphere (where temperature initially remains constant then increases due to ozone absorption of UV radiation). It acts as a "lid" on convection — cumulonimbus clouds that reach it spread out laterally to form the characteristic anvil shape. Jet streams are located near the tropopause. #### Source - [?] Source non identifiée ### Q17: In which unit are temperatures reported by European meteorological aviation services? ^t50q17 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q17) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q17) - **A)** Degrees Fahrenheit - **B)** Kelvin - **C)** Degrees Centigrade (°C) - **D)** Gpdam #### Answer C) #### Explanation European aviation meteorology (ICAO Annex 3, EU regulations) specifies temperatures in degrees Celsius (°C) for all operational products including METARs, TAFs, SIGMETs, and forecast charts. Kelvin is used in scientific and upper-air calculations. Fahrenheit is used in the US and a few other countries but not in European aviation. This standardisation is critical for correct interpretation of icing levels, freezing level heights, and density altitude. #### Key Terms ICAO = International Civil Aviation Organization #### Source - [?] Source non identifiée ### Q18: What is meant by an "inversion layer"? ^t50q18 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q18) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q18) - A) An atmospheric layer where temperature increases with increasing height - B) A boundary area between two other layers within the atmosphere - C) An atmospheric layer with constant temperature with increasing height - D) An atmospheric layer where temperature decreases with increasing height #### Answer A) #### Explanation An inversion "inverts" the normal lapse rate — instead of temperature falling with height, it rises. This creates a very stable layer that acts as a lid on convection, trapping thermals below it, concentrating pollutants, and promoting fog and low cloud formation beneath it. For glider pilots, a low-level inversion caps thermal height; a subsidence inversion in a high-pressure system limits soaring altitude and is often associated with haze. #### Source - [VV Q30 p.113](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=113) (score: 0.27) - [QuizVDS Q18](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q18): Answer A - PDF Answer: D ### Q19: What is meant by an "isothermal layer"? ^t50q19 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q19) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q19) - **A)** An atmospheric layer where temperature increases with increasing height - **B)** A boundary area between two other layers within the atmosphere - **C)** An atmospheric layer where temperature decreases with increasing height - **D)** An atmospheric layer with constant temperature with increasing height #### Answer D) #### Explanation An isothermal layer maintains constant temperature with increasing altitude. Like an inversion, it is more stable than the standard atmosphere and inhibits convection. The lower stratosphere exhibits an isothermal region immediately above the tropopause. Isothermal layers can also occur in the troposphere and, like inversions, act as a cap on thermal development and cloud growth. #### Source - [VV Q30 p.113](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=113) (score: 0.27) - [QuizVDS Q19](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q19): Answer B - PDF Answer: D ### Q20: The temperature lapse rate with increasing altitude within the troposphere according to ISA is ^t50q20 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q20) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q20) - **A)** 3° C / 100 m. - **B)** 0.65° C / 100 m. - **C)** 1° C / 100 m. - **D)** 0.6° C / 100 m. #### Answer B) #### Explanation The ISA Environmental Lapse Rate (ELR) is 6.5°C per 1000 m, or 0.65°C per 100 m (approximately 2°C per 1000 ft). This is distinct from the Dry Adiabatic Lapse Rate (DALR) of 1°C/100 m and the Saturated Adiabatic Lapse Rate (SALR) of approximately 0.6°C/100 m. When the actual ELR is steeper than the DALR, the atmosphere is absolutely unstable; when it lies between the DALR and SALR, the atmosphere is conditionally unstable — the typical situation for thermal soaring. #### Key Terms ISA = International Standard Atmosphere #### Source - [S1S Q1 p.40](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Specifiques.pdf#page=40) (score: 0.23) - [QuizVDS Q20](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q20): Answer C ### Q21: Which process may produce an inversion layer at around 5000 ft (1500 m) altitude? ^t50q21 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q21) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q21) - A) Advection of cool air in the upper troposphere - B) Intensive sunlight insolation during a warm summer day - C) Ground cooling by radiation during the night - D) Widespread descending air within a high pressure area #### Answer D) #### Explanation Subsidence inversion forms when air in the centre of a high-pressure area sinks over a wide area. As the air descends, it warms adiabatically, but because the lower air has not warmed at the same rate, the descending layer becomes warmer than the air below it — creating an inversion, typically around 1500–3000 m. This is characteristic of anticyclonic conditions: stable weather, limited convection, and haze or smog trapped below the inversion. #### Source - [?] Source non identifiée ### Q22: A ground-level inversion can be caused by ^t50q22 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q22) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q22) - **A)** Ground cooling during the night. - **B)** Intensifying and gusting winds. - **C)** Large-scale lifting of air. - **D)** Thickening of clouds in medium layers. #### Answer A) #### Explanation Radiation inversion forms on calm, clear nights when the ground radiates heat into space and cools rapidly. The air in contact with the ground also cools, while air a few hundred metres above remains warmer — creating a temperature inversion near the surface. This type of inversion is common in anticyclonic conditions and often produces radiation fog or low stratus in the morning, which burns off as the sun heats the ground. #### Source - [?] Source non identifiée ### Q23: What is the ISA standard pressure at FL 180 (5500 m)? ^t50q23 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q23) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q23) - **A)** 300 hPa - **B)** 500 hPa - **C)** 1013.25 hPa - **D)** 250 hPa #### Answer B) #### Explanation In the International Standard Atmosphere, pressure at approximately 5500 m (FL180) is 500 hPa — exactly half the sea-level pressure of 1013.25 hPa. The 500 hPa level is a key reference level in synoptic meteorology and is used extensively in upper-air charts. Pressure decreases approximately logarithmically with altitude, halving roughly every 5500 m in the lower troposphere. #### Key Terms - **FL** = Flight Level - **ISA** = International Standard Atmosphere #### Source - [VV Q15 p.110](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=110) (score: 0.27) - [QuizVDS Q23](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q23): Answer D - PDF Answer: D ### Q24: Which processes lead to decreasing air density? ^t50q24 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q24) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q24) - A) Decreasing temperature, decreasing pressure - B) Increasing temperature, increasing pressure - C) Decreasing temperature, increasing pressure - D) Increasing temperature, decreasing pressure #### Answer D) #### Explanation Air density is governed by the ideal gas law: density = pressure / (specific gas constant × temperature). Density decreases when pressure decreases (fewer molecules per unit volume) or when temperature increases (molecules move faster and spread apart). Both increasing temperature AND decreasing pressure simultaneously reduce density most effectively. This is why density altitude (the altitude equivalent of the actual air density) matters for aircraft performance on hot, high-altitude airfields. #### Source - [VV Q139 p.240](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=240) (score: 0.25) - [QuizVDS Q24](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q24): Answer C - PDF Answer: B ### Q25: The pressure at MSL under ISA conditions is ^t50q25 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q25) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q25) - **A)** 1123 hPa. - **B)** 113.25 hPa. - **C)** 15 hPa. - **D)** 1013.25 hPa. #### Answer D) #### Explanation The ISA (ICAO Standard Atmosphere) defines sea-level pressure as 1013.25 hPa (also expressed as 29.92 inHg in US aviation). This is the standard QNE setting — with 1013.25 hPa set on the altimeter subscale, the instrument reads Flight Level. All pressure altitudes and flight level definitions are based on this datum. Actual sea-level pressure varies with weather systems and must be corrected via QNH for accurate altitude indication. #### Key Terms - **ISA** = International Standard Atmosphere - **QNH** = Pressure adjusted to mean sea level - **ICAO** = International Civil Aviation Organization - **MSL** = Mean Sea Level - **QNE** = Standard pressure setting (1013.25 hPa) #### Source - [VV Q15 p.110](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=110) (score: 0.21) - [QuizVDS Q25](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q25): Answer A - PDF Answer: D ### Q26: At what height is the ISA tropopause located? ^t50q26 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q26) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q26) - A) 48000 ft. - B) 11000 ft. - C) 36000 ft. - D) 5500 ft #### Answer C) #### Explanation The ISA tropopause is located at 11,000 m, which equals approximately 36,089 ft (effectively 36,000 ft). Above this level, the standard atmosphere defines a constant temperature of -56.5°C up to 20,000 m (the isothermal stratospheric layer). This is distinct from Q15 which asks in metres — both questions test knowledge of the same value expressed in different units. #### Key Terms ISA = International Standard Atmosphere #### Source - [?] Source non identifiée ### Q27: The barometric altimeter shows height above ^t50q27 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q27) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q27) - A) Mean sea level. - B) Ground. - C) Standard pressure 1013.25 hPa. - D) A selected reference pressure level. #### Answer D) #### Explanation The barometric altimeter measures atmospheric pressure and converts it to altitude based on the ISA pressure-altitude relationship. Crucially, it indicates height above whatever pressure level is set on the subscale (Kollsman window). Set QNH and it reads altitude above mean sea level; set QFE and it reads height above the reference airfield; set 1013.25 hPa (QNE) and it reads flight level. The altimeter always references a pressure level, not a physical surface. #### Key Terms - **ISA** = International Standard Atmosphere - **QNH** = Pressure adjusted to mean sea level - **QFE** = Atmospheric pressure at aerodrome elevation - **QNE** = Standard pressure setting (1013.25 hPa) #### Source - [VV Q15 p.110](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=110) (score: 0.41) - [QuizVDS Q27](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q27): Answer B - PDF Answer: D ### Q28: The altimeter can be checked on the ground by setting ^t50q28 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q28) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q28) - A) QFE and comparing the indication with the airfield elevation. - B) QNH and comparing the indication with the airfield elevation. - C) QFF and comparing the indication with the airfield elevation. - D) QNE and checking that the indication shows zero on the ground. #### Answer B) #### Explanation QNH is the local altimeter setting that makes the instrument read the airfield's elevation above mean sea level when on the ground. Setting QNH and checking that the altimeter reads the known airfield elevation (published in AIP/chart) verifies the altimeter is functioning correctly and calibrated. QFE would show zero (height above airfield), QNE (1013.25) would show a value unrelated to actual elevation, and QFF is a meteorological value reduced to MSL for surface analysis charts. #### Key Terms - **QNH** = Pressure adjusted to mean sea level - **QFE** = Atmospheric pressure at aerodrome elevation - **AIP** = Aeronautical Information Publication - **MSL** = Mean Sea Level - **QNE** = Standard pressure setting (1013.25 hPa) #### Source - [VV Q20 p.111](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=111) (score: 0.22) - [QuizVDS Q28](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q28): Answer C - PDF Answer: C ### Q29: With QFE set, the barometric altimeter indicates ^t50q29 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q29) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q29) - A) Height above MSL. - B) True altitude above MSL. - C) Height above standard pressure 1013.25 hPa. - D) Height above the pressure level at airfield elevation. #### Answer D) #### Explanation QFE is the actual atmospheric pressure at airfield elevation. When set on the altimeter subscale, the instrument reads zero on the ground at the reference airfield and subsequently indicates height above that reference pressure level — effectively height above the airfield. This setting is commonly used in circuit flying and gliding operations so the altimeter directly reads AGL height at the home airfield. It does not account for terrain elevation differences elsewhere. #### Key Terms - **QFE** = Atmospheric pressure at aerodrome elevation - **AGL** = Above Ground Level - **MSL** = Mean Sea Level #### Source - [VV Q77 p.162](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=162) (score: 0.38) - [QuizVDS Q29](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q29): Answer B - PDF Answer: A ### Q30: With QNH set, the barometric altimeter indicates ^t50q30 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q30) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q30) - A) Height above MSL - B) Height above the pressure level at airfield elevation. - C) Height above standard pressure 1013.25 hPa. - D) True altitude above MSL. #### Answer A) #### Explanation QNH is the altimeter setting adjusted so the instrument reads the airfield elevation above mean sea level (MSL) when on the ground. It is calculated by reducing the airfield QFE to sea level using the ISA temperature gradient. With QNH set, the altimeter shows **indicated altitude above MSL** — this is height referenced to MSL, which is why answer A is correct. However, indicated altitude is not the same as true altitude. In non-standard temperature conditions, the actual height above MSL can differ from the indicated reading. Answer D ("True altitude above MSL") is therefore wrong — QNH does not correct for temperature deviations from ISA. - **Option B** describes what QFE gives (height above airfield), not QNH. - **Option C** describes what happens with the standard setting 1013.25 hPa (flight levels), not QNH. #### Key Terms - **QNH** = Pressure adjusted to mean sea level - **QFE** = Atmospheric pressure at aerodrome elevation - **ISA** = International Standard Atmosphere - **MSL** = Mean Sea Level #### Source - [VV Q77 p.162](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=162) (score: 0.43) - [QuizVDS Q30](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q30): Answer B - PDF Answer: A ### Q31: How can wind speed and direction be determined from surface weather charts? ^t50q31 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q31) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q31) - A) By alignment and distance of hypsometric lines - B) By alignment of warm- and cold front lines. - C) By annotations from the text part of the chart - D) By alignment and distance of isobaric lines #### Answer D) #### Explanation Isobars (lines of equal pressure) on surface weather charts reveal both wind direction and speed: - **Wind direction:** Above the friction layer (~600-1000 m AGL), wind flows parallel to isobars (geostrophic wind). Near the surface, friction causes the wind to cross isobars at 10-30 degrees toward lower pressure. In the Northern Hemisphere, wind blows anticlockwise around lows and clockwise around highs (Buys-Ballot's Law). - **Wind speed:** The pressure gradient force (PGF) drives wind from high to low pressure. Closely spaced isobars = strong gradient = strong winds. Widely spaced isobars = weak gradient = light winds. - **Why not the other options?** Hypsometric lines (A) show height contours on upper-level charts, not surface charts. Front lines (B) show air mass boundaries but do not directly indicate wind speed. Text annotations (C) may supplement but are not how wind is determined from the chart itself. #### Key Terms - **Isobar** = line connecting points of equal atmospheric pressure - **Geostrophic wind** = wind flowing parallel to isobars where PGF and Coriolis force are in balance - **PGF** = Pressure Gradient Force, the force driving air from high to low pressure - **Buys-Ballot's Law** = with your back to the wind in the Northern Hemisphere, low pressure is to your left - **Hypsometric lines** = contour lines of geopotential height on upper-air charts (not surface charts) - **Friction layer** = lowest ~600-1000 m of the atmosphere where surface drag affects wind #### Source - [?] Source non identifiée ### Q32: Which force is responsible for causing "wind"? ^t50q32 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q32) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q32) - **A)** Coriolis force - **B)** Thermal force - **C)** Pressure gradient force - **D)** Centrifugal force #### Answer C) #### Explanation Wind is initiated by the pressure gradient force (PGF) — air accelerates from high pressure toward low pressure due to differences in atmospheric pressure. The Coriolis force deflects the moving air (to the right in the Northern Hemisphere) but does not cause the initial motion. Centrifugal force acts in curved flow around pressure systems. Thermal effects create pressure differences which then drive the PGF. Without a pressure gradient there would be no wind. #### Source - [ ] ≈ [[Examen Blanc/Questionnaire toutes branches VV.pdf#page=5|VV Q15 p.5]] (clé: **A**) ### Q33: Above the friction layer, with a prevailing pressure gradient, the wind direction is ^t50q33 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q33) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q33) - **A)** Perpendicular to the isohypses. - **B)** Perpendicular to the isobars. - **C)** Parallel to the isobars. - **D)** At an angle of 30° to the isobars towards low pressure. #### Answer C) #### Explanation Above the friction layer (roughly 600–1000 m AGL), the Coriolis force and pressure gradient force balance each other, producing geostrophic flow parallel to the isobars. In the friction layer below, surface drag slows the wind, reduces the Coriolis deflection, and allows the wind to cross isobars at an angle toward lower pressure (typically 10–30°). Understanding this is essential for predicting wind direction at altitude versus near the surface. #### Key Terms AGL = Above Ground Level #### Source - [?] Source non identifiée ### Q34: Which of the listed surfaces causes the greatest wind speed reduction due to ground friction? ^t50q34 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q34) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q34) - A) Flat land, deserted land, no vegetation - B) Oceanic areas - C) Flat land, lots of vegetation cover - D) Mountainous areas, vegetation cover #### Answer D) #### Explanation Surface roughness (aerodynamic roughness length) determines how much friction the surface exerts on moving air. Mountainous terrain with vegetation has the highest roughness length, causing maximum turbulent drag and wind speed reduction. Oceans have very low roughness and exert minimal friction. Flat vegetated land is intermediate. Importantly, mountains also mechanically block and deflect wind, creating additional complex flow patterns, turbulence, and wave phenomena of direct relevance to glider pilots. #### Source - [?] Source PDF non identifiée (original: **A**) ### Q35: The movement of air flowing together is called ^t50q35 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q35) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q35) - **A)** Divergence. - **B)** Subsidence. - **C)** Concordence. - **D)** Convergence. #### Answer D) #### Explanation Convergence describes air flowing into a region from different directions, compressing horizontally. By mass continuity, converging surface air must go somewhere — it is forced upward, triggering cloud formation, precipitation, and potentially convective development. Convergence zones are important for glider pilots as they produce enhanced lift along their axes; sea-breeze fronts and col zones between pressure systems are classic convergence sources for soaring. #### Source - [?] Source non identifiée ### Q36: The movement of air flowing apart is called ^t50q36 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q36) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q36) - **A)** Convergence. - **B)** Subsidence. - **C)** Divergence. - **D)** Concordence. #### Answer C) #### Explanation Divergence describes air spreading outward from a region. At the surface, divergence causes subsiding air from above to replace the outflowing air, promoting stability, clear skies, and fair weather. High-pressure anticyclones are associated with surface divergence and upper-level convergence. In the upper troposphere, divergence above a surface low enhances upward motion and intensifies the low-pressure system. #### Source - [?] Source non identifiée ### Q37: What weather development results from convergence at ground level? ^t50q37 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q37) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q37) - **A)** Descending air and cloud dissipation - **B)** Ascending air and cloud formation - **C)** Descending air and cloud formation - **D)** Ascending air and cloud dissipation #### Answer B) #### Explanation Surface convergence forces air upward (ascending motion) by mass continuity — air cannot accumulate indefinitely at the surface. As air rises, it cools at the dry adiabatic lapse rate until it reaches the dew point (lifting condensation level), where condensation begins and clouds form. Further ascent releases latent heat, potentially fuelling deep convection. This is the fundamental mechanism behind frontal lifting and sea-breeze convergence lift. #### Source - [VV Q94 p.126](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=126) (score: 0.20) - [QuizVDS Q37](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q37): Answer A - PDF Answer: A ### Q38: When air masses meet each other head on, what is this referred to and what air movements follow? ^t50q38 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q38) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q38) - **A)** Divergence resulting in sinking air - **B)** Convergence resulting in air being lifted - **C)** Divergence resulting in air being lifted - **D)** Convergence resulting in sinking air #### Answer B) #### Explanation When two opposing air flows collide head-on, the meeting zone is a convergence line. The colliding air has nowhere to go horizontally and is forced upward — producing ascending motion, cloud formation, and potentially precipitation or thunderstorms. This occurs at fronts, sea-breeze convergence zones, and col zones. Glider pilots exploit convergence lines for extended linear climbs along the lift band. #### Source - [?] Source non identifiée ### Q39: By which air masses is Central Europe mainly influenced? ^t50q39 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q39) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q39) - **A)** Tropical and arctic cold air - **B)** Arctic and polar cold air - **C)** Equatorial and tropical warm air - **D)** Polar cold air and tropical warm air #### Answer D) #### Explanation Central Europe sits in the mid-latitude westerly belt between the polar front (cold polar air from the north) and subtropical high pressure (warm tropical air from the south). The interaction between these two contrasting air masses creates the characteristic mid-latitude cyclone (depression) weather of Central Europe: frontal systems, rapidly changing weather, and the full range of cloud types and precipitation. This dynamic contrast also drives the polar jet stream overhead. #### Source - [S1C Q14 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.29) - [QuizVDS Q39](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q39): Answer D - PDF Answer: A ### Q40: In terms of global atmospheric circulation, where does polar cold air meet subtropical warm air? ^t50q40 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q40) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q40) - **A)** At the equator - **B)** At the geographic poles - **C)** At the polar front - **D)** At the subtropical high pressure belt #### Answer C) #### Explanation The polar front is the boundary between the polar cell (cold, dense air flowing equatorward) and the Ferrel cell (relatively warmer mid-latitude air). In the Northern Hemisphere it is located roughly between 40–60°N, but its position fluctuates as waves (Rossby waves) develop along it — these waves amplify into cyclones and anticyclones. The jet stream flows along the polar front and is a critical factor in synoptic weather patterns across Europe. #### Source - [?] Source non identifiée ### Q41: "Foehn" conditions typically develop with ^t50q41 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q41) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q41) - **A)** Instability, widespread air blown against a mountain ridge. - **B)** Stability, high pressure area with calm wind. - **C)** Instability, high pressure area with calm wind. - **D)** Stability, widespread air blown against a mountain ridge. #### Answer D) #### Explanation Foehn is a warm, dry, descending wind on the lee side of a mountain range. It develops when stable air is pushed by a broad-scale pressure gradient against a mountain barrier. On the windward side, moist air rises and cools at the Saturated Adiabatic Lapse Rate (SALR ~0.6°C/100 m) after reaching the dew point, precipitating moisture. On the lee side, dry air descends at the Dry Adiabatic Lapse Rate (DALR ~1°C/100 m), arriving warmer and drier than it started — the Foehn effect. #### Source - [?] Source non identifiée ### Q42: What type of turbulence is typically encountered close to the ground on the lee side during Foehn conditions? ^t50q42 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q42) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q42) - **A)** Thermal turbulence - **B)** Inversion turbulence - **C)** Turbulence in rotors - **D)** Clear-air turbulence (CAT) #### Answer C) #### Explanation During Foehn and mountain wave conditions, a rotor zone develops in the lower troposphere on the lee side beneath the crests of the standing waves. The rotor is a region of intense, chaotic turbulence with rotating air, strong downdrafts, and violent eddies — it is one of the most hazardous phenomena for aircraft. Lenticular clouds (altocumulus lenticularis) mark wave crests above, while rotor clouds (roll clouds) mark the rotor zone near the surface. #### Source - [?] Source non identifiée ### Q43: Light turbulence should always be expected ^t50q43 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q43) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q43) - **A)** Below stratiform clouds in medium layers. - **B)** Above cumulus clouds due to thermal convection. - **C)** When entering inversions. - **D)** Below cumulus clouds due to thermal convection. #### Answer D) #### Explanation Cumulus clouds are the visible tops of thermal columns. The sub-cloud layer beneath them contains active thermals (updraughts) and compensating downdraughts between them, creating light to moderate turbulence from convective mixing. This is the normal turbulent environment of thermal soaring. Above cumulus tops the air is generally smoother (outside the cloud); stratiform clouds have minimal convective turbulence unless embedded CBs are present. #### Source - [?] Source non identifiée ### Q44: Moderate to severe turbulence should be expected ^t50q44 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q44) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q44) - **A)** With the appearance of extended low stratus clouds (high fog). - **B)** Below thick cloud layers on the windward side of a mountain range. - **C)** Overhead unbroken cloud layers. - **D)** On the lee side of a mountain range when rotor clouds are present. #### Answer D) #### Explanation Rotor clouds (roll clouds) on the lee side of mountains are the visible indicator of the highly turbulent rotor zone beneath mountain waves. This turbulence can be extreme, with unpredictable up- and downdraughts, strong shear, and rotational forces capable of exceeding aircraft structural limits. Experienced wave pilots avoid or transit the rotor zone quickly with sufficient airspeed. The windward side of mountains typically has orographic cloud and steady lift, not severe turbulence. #### Source - [?] Source non identifiée ### Q45: Which answer lists every state of water found in the atmosphere? ^t50q45 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q45) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q45) - **A)** Gaseous and liquid - **B)** Liquid and solid - **C)** Liquid - **D)** Liquid, solid, and gaseous #### Answer D) #### Explanation Water exists in all three states within the Earth's atmosphere. Gaseous water vapour is invisible and present throughout the troposphere. Liquid water forms cloud droplets, rain, and drizzle. Solid water forms ice crystals (cirrus clouds), snow, hail, and graupel. Understanding all three states is essential for icing awareness: supercooled liquid water droplets (liquid below 0°C) pose the greatest structural icing hazard to aircraft, as they freeze on contact with cold surfaces. #### Source - [VV Q39 p.115](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=115) (score: 0.21) - [QuizVDS Q45](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q45): Answer A - PDF Answer: A ### Q46: How do dew point and relative humidity change when temperature decreases? ^t50q46 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q46) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q46) - **A)** Dew point increases, relative humidity decreases - **B)** Dew point remains constant, relative humidity decreases - **C)** Dew point decreases, relative humidity increases - **D)** Dew point remains constant, relative humidity increases #### Answer D) #### Explanation The dew point is the temperature to which air must be cooled (at constant pressure and moisture content) for saturation to occur. It is a measure of the absolute moisture content and remains constant as temperature changes (assuming no moisture is added or removed). However, relative humidity — the ratio of actual vapour pressure to saturation vapour pressure — increases as temperature falls, because the saturation vapour pressure decreases with temperature. When temperature equals the dew point, relative humidity reaches 100% and condensation begins. #### Source - [S2 Q15 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.33) - [QuizVDS Q46](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q46): Answer B ### Q47: How do spread and relative humidity change when temperature increases? ^t50q47 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q47) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q47) - **A)** Spread remains constant, relative humidity decreases - **B)** Spread increases, relative humidity increases - **C)** Spread increases, relative humidity decreases - **D)** Spread remains constant, relative humidity increases #### Answer C) #### Explanation Spread is the temperature-dew point difference (T - Td). As temperature increases while dew point remains constant, the spread widens. Simultaneously, because warmer air can hold more water vapour, the relative humidity decreases — the air is now further from saturation. A large spread indicates dry air and a high lifting condensation level (high cloud base). A small spread (near zero) indicates saturated or near-saturated conditions, with fog or low cloud likely. #### Source - [S2 Q15 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.35) - [QuizVDS Q47](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q47): Answer C ### Q48: The "spread" is defined as ^t50q48 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q48) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q48) - **A)** Maximum amount of water vapour that can be contained in air. - **B)** Relation of actual to maximum possible humidity of air. - **C)** Difference between dew point and condensation point. - **D)** Difference between actual temperature and dew point. #### Answer D) #### Explanation Spread (also called dew point depression) is simply the difference between the air temperature and the dew point temperature: Spread = T - Td. It is used to estimate cloud base height: in temperate latitudes, cloud base height in metres above the surface is approximately spread × 125 (or in feet, spread × 400). A spread of 0 means the air is saturated (fog or cloud at the surface). Spread is a quick indicator of moisture availability for soaring pilots. #### Source - [?] Source non identifiée ### Q49: With other factors remaining constant, decreasing temperature results in ^t50q49 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q49) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q49) - **A)** Increasing spread and decreasing relative humidity. - **B)** Decreasing spread and decreasing relative humidity. - **C)** Decreasing spread and increasing relative humidity. - **D)** Increasing spread and increasing relative humidity. #### Answer C) #### Explanation As temperature decreases (with dew point unchanged), the gap between temperature and dew point narrows — spread decreases. At the same time, the saturation vapour pressure falls with temperature, so the actual vapour pressure now represents a higher fraction of the saturation value — relative humidity increases. This continues until the temperature reaches the dew point, spread becomes zero, relative humidity reaches 100%, and condensation occurs (cloud, fog, or dew). #### Source - [?] Source non identifiée ### Q50: What process causes latent heat to be released into the upper troposphere? ^t50q50 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q50) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q50) - **A)** Evaporation over widespread water areas - **B)** Descending air across widespread areas - **C)** Stabilisation of inflowing air masses - **D)** Cloud forming due to condensation #### Answer D) #### Explanation When water vapour condenses into cloud droplets, the latent heat stored during evaporation is released into the surrounding air. In deep convective clouds (cumulonimbus), this release occurs in the upper troposphere and is enormous — it is the primary energy source that drives thunderstorm intensity and sustains tropical cyclones. The released latent heat warms the rising air parcel, making it more buoyant relative to the environment and accelerating further ascent, which is why the Saturated Adiabatic Lapse Rate (SALR) is less steep than the Dry Adiabatic Lapse Rate (DALR). #### Source - [?] Source non identifiée ### Q51: Which of these clouds poses the greatest danger to aviation? ^t50q51 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q51) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q51) - **A)** Altocumulus - **B)** Cumulonimbus - **C)** Cirrostratus - **D)** Cirrocumulus #### Answer B) #### Explanation The CB (cumulonimbus) is the most dangerous cloud: severe turbulence, lightning, hail, wind shear, icing. #### Key Terms CB = Cumulonimbus (thunderstorm cloud) #### Source - [S1C Q10 p.21](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=21) (score: 0.79) - PDF Answer: C ### Q52: In which situation is the tendency for thunderstorms most pronounced? ^t50q52 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q52) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q52) - A) High pressure situation, significant warming of the lower air layers, low air humidity. - B) Slack pressure gradient situation, significant warming of the upper air layers, high air humidity. - C) Slack pressure gradient situation, significant cooling of the lower air layers, high air humidity. - D) Slack pressure gradient situation, significant warming of the lower air layers, high air humidity. #### Answer D) #### Explanation Thunderstorms = slack pressure gradient (low pressure gradient) + strong surface heating (instability) + high humidity. #### Source - [S1C Q19 p.23](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=23) (score: 1.00) - PDF Answer: C ### Q53: Fine suspended water droplets reduce visibility at an aerodrome to only 1.5 km up to 1000 ft AGL. What meteorological phenomenon causes this? ^t50q53 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q53) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q53) - **A)** Haze (HZ). - **B)** Mist (BR). - **C)** Widespread dust (DU). - **D)** Shallow fog (MIFG). #### Answer B) #### Explanation Visibility 1–5 km with water droplets = mist (BR). Fog = visibility < 1 km. #### Key Terms AGL = Above Ground Level #### Source - [S1C Q11 p.21](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=21) (score: 0.52) - PDF Answer: A ### Q54: Which of the following situations most favours radiation fog formation? ^t50q54 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q54) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q54) - A) 15 kt / Overcast / 13°C / Dew point 12°C - B) 15 kt / Clear sky / 16°C / Dew point 15°C - C) 2 kt / Scattered cloud / 7°C / Dew point 6°C - D) 2 kt / Clear sky / -3°C / Dew point -20°C #### Answer C) #### Explanation Radiation fog: light wind (2 kt), small temperature/dew point spread (1°C), some cloud acceptable. Option **(C)** has too large a temp/dew point spread. #### Source - [S1C Q12 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.60) - PDF Answer: B ### Q55: The temperature recorded at Samedan airport (LSZS, AD elevation 5600 ft) is +5°C. What will the approximate temperature be at 8600 ft altitude directly above the airport? (Assume ISA lapse rate) ^t50q55 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q55) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q55) - **A)** +5°C - **B)** +11°C - **C)** -1°C - **D)** -6°C #### Answer C) #### Explanation ISA lapse rate = -2°C/1000 ft. Difference: 8600 - 5600 = 3000 ft. Temperature: 5°C - (3 × 2) = -1°C. #### Key Terms ISA = International Standard Atmosphere #### Source - [S1C Q1 p.20](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=20) (score: 0.70) - PDF Answer: A ### Q56: The QFE of an aerodrome (AD elevation 3500 ft) corresponds to: ^t50q56 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q56) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q56) - A) The instantaneous pressure at sea level. - B) The instantaneous pressure at the measurement station level reduced to sea level taking into account the ISA temperature lapse rate. - C) The instantaneous pressure at the measurement station level. - D) The instantaneous pressure at the measurement station level reduced to sea level taking into account the actual temperature profile. #### Answer C) #### Explanation QFE = atmospheric pressure measured at aerodrome level (station). The altimeter reads 0 on the ground. #### Key Terms - **QFE** = Atmospheric pressure at aerodrome elevation - **ISA** = International Standard Atmosphere #### Source - [S1C Q2 p.20](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=20) (score: 0.73) - PDF Answer: C ### Q57: What does the following wind barb symbol mean? ^t50q57 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q57) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q57) ![](figures/t50_q57.png) - A) Wind from NE, 30 knots. - B) Wind from SW, 30 knots. - C) Wind from SW, 15 knots. - D) Wind from NE, 15 knots. #### Answer D) #### Explanation A wind barb is the standard meteorological symbol for wind direction and speed. It has two ends: a **station end** (the dot) and a **barbed end** (the staff with feathers). The **feathers point toward where the wind is coming FROM** — i.e., the barbed end is upwind. Speed is read off the feathers: - Pennant (filled triangle) = 50 kt - Long barb (full feather) = 10 kt - Short barb (half feather) = 5 kt In this symbol the staff goes from the dot to the **NE**, with one **long barb (10 kt)** and one **short barb (5 kt)** = **15 kt**. So the wind is **from the NE at 15 kt**. ![](figures/wind_barb_key.png) Reference: [Wikipedia — Station model § Wind](https://en.wikipedia.org/wiki/Station_model#Wind) #### Source - [S1C Q6 p.21](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=21) (score: 1.00) - PDF Answer: C ### Q58: What are the wind speed and direction in the following METAR? LSZB 131220Z 28015G25KT 9999 SCT035 BKN075 10/06 Q1018 NOSIG= ^t50q58 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q58) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q58) - **A)** Wind from WNW, 15 knots, gusting to 25 knots. - **B)** Wind from ESE, 15 knots, gusting to 25 knots. - **C)** Wind from WNW, 25 knots, direction varying between WNW and SSE. - **D)** Wind from WNW, 15 knots, direction varying between WNW and WSW. #### Answer A) #### Explanation 280° = WNW, 15 kt mean, G25 = gusts to 25 kt. #### Key Terms METAR = Aerodrome routine weather report #### Source - [S1C Q3 p.20](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=20) (score: 0.82) - PDF Answer: D ### Q59: In Switzerland, cloud base in a METAR is given in ^t50q59 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q59) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q59) - A) ...metres above sea level. - B) ...metres above aerodrome level. - C) ...feet above aerodrome level. - D) ...feet above sea level. #### Answer C) #### Explanation In a METAR, cloud base is given in feet AGL (above aerodrome level). #### Key Terms - **AGL** = Above Ground Level - **METAR** = Aerodrome routine weather report #### Source - [S1C Q9 p.21](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=21) (score: 0.83) - PDF Answer: C ### Q60: You are flying at very high altitude (northern hemisphere) and consistently have a crosswind from the left. You conclude that: ^t50q60 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q60) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q60) - A) A high-pressure area is to the right of your track, a low-pressure area to the left. - B) There is a low-pressure area ahead of you and a high-pressure area behind you. - C) There is a high-pressure area ahead of you and a low-pressure area behind you. - D) A high-pressure area is to the left of your track, a low-pressure area to the right. #### Answer A) #### Explanation Buys-Ballot's law: standing with your back to the wind in the northern hemisphere, the low-pressure area is to your left. Wind from the left = low pressure to the left, high pressure to the right. #### Source - [S1C Q5 p.20](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=20) (score: 0.53) - PDF Answer: D ### Q61: Based on the synoptic chart, what change in atmospheric pressure is likely at point C in the coming hours? ^t50q61 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q61) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q61) > **Synoptic chart:** > ![](figures/t50_q61.png) > *T = depression centre. A = warm sector (between warm front and cold front). B = behind the cold front (cold air mass). C = ahead of the warm front (cool air mass).* > *Cold front: blue triangles. Warm front: red semicircles.* - **A)** No notable change. - **B)** Pressure will fall. - **C)** Pressure will rise. - **D)** Pressure will undergo rapid, irregular variations. #### Answer B) #### Explanation Point C lies ahead of the warm front, meaning the depression centre and its associated frontal system are approaching. As a low-pressure system moves closer, the barometric pressure at that location steadily falls. - **Option A** is wrong because an approaching depression always causes pressure changes. - **Option C** (pressure rise) would apply to a location behind a cold front where cold dense air moves in. - **Option D** (rapid irregular variations) is more typical of the immediate vicinity of thunderstorm activity, not the broad-scale approach of a warm front. #### Source - [S1C Q15 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.38) - PDF Answer: D ### Q62: Which phenomenon is typical during the summer passage of an unstable cold front? ^t50q62 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q62) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q62) - **A)** Stratiform cloud cover. - **B)** Convective cloud development. - **C)** Rapid temperature rise behind the front. - **D)** Rapid pressure drop behind the front. #### Answer B) #### Explanation An unstable cold front in summer forces warm, moist, unstable air upward vigorously, triggering strong convection and the development of cumuliform clouds including towering cumulus and cumulonimbus with showers and thunderstorms. - Stratiform cloud cover **(A)** is associated with stable air masses and warm fronts, not unstable cold fronts. - Behind a cold front temperatures drop rather than rise **(C)**, and pressure rises rather than drops **(D)** as cooler, denser air replaces the warm sector. #### Source - [S1C Q13 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.27) - PDF Answer: D ### Q63: What is most likely to happen when a stable, warm, humid air mass slides over a cold air mass? ^t50q63 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q63) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q63) - **A)** A few scattered cumuliform clouds, rare precipitation, light turbulence, and excellent visibility. - **B)** Extensive stratiform clouds with a gradually lowering cloud base and continuous rainfall. - **C)** Convective clouds, heavy showers, thunderstorm tendency, and severe turbulence. - **D)** Rapid drying aloft with cloud dissipation and good visibility, but dense fog in the lowlands. #### Answer B) #### Explanation When stable warm humid air overrides a cold air mass (the classic warm front mechanism), the warm air ascends gently along the frontal surface, cooling progressively and forming widespread stratiform clouds — from high cirrus down through altostratus to nimbostratus — with continuous, steady precipitation and a lowering cloud base. - **Option A** describes fair-weather conditions unrelated to frontal activity. - **Option C** describes unstable convective weather typical of cold fronts, not warm fronts. - **Option D** combines fog with drying aloft, which is internally contradictory and not a recognised frontal pattern. #### Source - [S1C Q18 p.23](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=23) (score: 0.43) - PDF Answer: D ### Q64: Which air mass is likely to produce showers in Central Europe in any season? ^t50q64 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q64) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q64) - **A)** Continental tropical air. - **B)** Maritime tropical air. - **C)** Continental polar air. - **D)** Maritime polar air. #### Answer D) #### Explanation Maritime polar air (mP) originates over cold northern oceans, picking up moisture and becoming unstable as it moves over relatively warmer European land surfaces, producing convective showers year-round. - Continental tropical air **(A)** is warm and dry, producing clear skies rather than showers. - Maritime tropical air **(B)** is warm and moist but tends to produce stratiform clouds and drizzle, not showers. - Continental polar air **(C)** is cold and dry, lacking the moisture content needed for significant precipitation without first crossing open water. #### Source - [S1C Q14 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.56) - PDF Answer: A ### Q65: Given this synoptic chart for the Alpine region, what hazards are you likely to encounter in Switzerland? ^t50q65 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q65) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q65) > **Synoptic chart Switzerland/Alps:** > ![](figures/t50_q65.png) > *Anticyclone (H) to the west, depression (T) to the north-east, isobars indicating NW flow over Switzerland.* - **A)** In winter, persistent snowfall in Ticino. - **B)** In summer, widespread thunderstorms south of the Alps with severe turbulence. - **C)** Continuous precipitation north of the Alps; very disturbed weather south of the Alps. - **D)** Cloud-covered Alps to the south; strong gusty winds north of the Alps. #### Answer C) #### Explanation A northwest flow situation (Nordwestlage) drives moist air against the northern slopes of the Alps, producing continuous orographic precipitation on the north side. The flow also disturbs conditions south of the Alps through spillover effects and forced subsidence turbulence. - **Option A** describes a south-side precipitation event (Stau from the south), not a northwest situation. - **Option B** misplaces the thunderstorms on the wrong side of the Alps. - **Option D** reverses the pattern — clouds would cover the north side, not the south. #### Source - [S1C Q17 p.23](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=23) (score: 0.52) - PDF Answer: C ### Q66: Referring to the Low Level SWC chart, which statement is correct? ^t50q66 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q66) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q66) > **Low Level Significant Weather Chart (OGDD70)** > ![](figures/t50_q66.png) > *Fixed Time Prognostic Chart — Valid: 09 UTC, 22 JAN 2015* > *Issued by MeteoSwiss* | Zone | Cloud cover | Cloud base | Cloud top | Visibility | Turbulence | Icing | |------|-----------|-------------|---------------|------------|------------|---------| | A | BKN/OVC SC, AC | 3000 ft | FL080 | > 10 km | MOD below FL080 | MOD FL040-FL080 | | B | BKN/OVC ST, SC | 1500 ft | FL060 | 5-8 km, locally 3 km (BR) | MOD below FL060 | MOD FL030-FL060 | | C | SCT/BKN CU, SC | 4000 ft | FL100 | > 10 km | ISOL MOD | LGT FL050-FL100 | > *0°C isotherm: FL040 (north) to FL060 (south). Surface wind: SW 15-25 kt.* - **A)** Isolated thunderstorms may occur in area C with no icing or turbulence. - **B)** In area B, cumuliform clouds are expected with possible light freezing rain or freezing fog. - **C)** Rain and snow showers are to be expected in area A. - **D)** Area A lies between two warm fronts. #### Answer C) #### Explanation Area A features BKN/OVC stratocumulus and altocumulus with moderate icing between FL040 and FL080 and the 0°C isotherm at FL040, indicating mixed precipitation — rain and snow showers — within this zone. - **Option A** incorrectly states no icing or turbulence in area C, whereas the chart shows isolated moderate turbulence and light icing there. - **Option B** mischaracterises area B, which has stratiform clouds (ST, SC), not cumuliform. - **Option D** makes an unsupported claim about warm fronts that cannot be verified from the chart data provided. #### Key Terms FL = Flight Level #### Source - [?] Source non identifiée ### Q67: On a sunny summer afternoon you are on final approach to an aerodrome whose runway runs parallel to the coastline, with the coast to your left. On this flat terrain, what direction will the thermal (sea breeze) wind come from? ^t50q67 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q67) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q67) - A) Crosswind from the left. - B) Headwind. - C) Tailwind. - D) Crosswind from the right. #### Answer A) #### Explanation During a sunny summer afternoon, the land heats faster than the sea, causing air to rise over land and drawing cooler air inland from the sea — this is the sea breeze. Since the coastline is to your left and the runway runs parallel to it, the sea breeze blows from the sea (left side) toward the land, creating a crosswind from the left. - **Options B and C** (headwind/tailwind) would require the wind to blow along the runway, not from the coast. - **Option D** would require the sea to be on the right side. #### Source - [S1C Q4 p.20](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=20) (score: 0.40) - PDF Answer: B ### Q68: Where are you most likely to experience strong winds and low-level turbulence? ^t50q68 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q68) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q68) - **A)** At the centre of an anticyclone. - **B)** In a transition zone between two air masses. - **C)** At the centre of a depression. - **D)** In a region of slack pressure gradient during winter. #### Answer B) #### Explanation Transition zones between air masses — i.e., frontal zones — feature steep horizontal temperature and pressure gradients that drive strong winds and generate mechanical and convective turbulence at low levels. - The centre of an anticyclone **(A)** is characterised by calm, subsiding air with light winds. - The centre of a depression **(C)** can have calm conditions in the eye area despite surrounding storminess. - Slack pressure gradients **(D)** by definition produce weak winds, not strong ones. #### Source - [S1C Q7 p.21](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=21) (score: 0.57) - PDF Answer: D ### Q69: An air mass at 10°C has a relative humidity of 45%. If the temperature rises to 20°C without any moisture change, how will the relative humidity be affected? ^t50q69 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q69) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q69) - **A)** It will increase by 50%. - **B)** It will remain constant. - **C)** It will decrease. - **D)** It will increase by 45%. #### Answer C) #### Explanation Relative humidity is the ratio of the actual water vapour content to the maximum the air can hold at that temperature. When temperature rises from 10°C to 20°C, the air's saturation capacity roughly doubles, but since no moisture is added, the actual vapour content stays the same — so relative humidity decreases significantly. - **Options A and D** wrongly claim humidity increases, which would require either adding moisture or cooling the air. - **Option B** is incorrect because relative humidity is temperature-dependent and cannot stay constant when temperature changes without a corresponding moisture change. #### Source - [S1C Q8 p.21](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=21) (score: 0.50) - PDF Answer: B ### Q70: On 1 June (summer time), you receive the Swiss GAFOR valid from 06:00 to 12:00 UTC. Your planned route shows "XMD". What does this mean? ^t50q70 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q70) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q70) - **A)** At 11:00 LT conditions on this route will be difficult. - **B)** At 09:00 LT conditions on this route will be critical. - **C)** At 09:00 LT the route will be closed. - **D)** At 11:00 LT the route will be closed. #### Answer C) #### Explanation The Swiss GAFOR divides the validity period (06:00–12:00 UTC) into three two-hour blocks. Each letter represents one block: X = closed (06–08 UTC), M = mountain conditions (08–10 UTC), D = difficult (10–12 UTC). On 1 June, summer time (CEST = UTC+2) applies, so 06–08 UTC = 08–10 LT. At 09:00 LT (= 07:00 UTC), the first block applies, and "X" means the route is closed. - **Option A and D** incorrectly interpret the timing or the code. - **Option B** confuses the category — "M" is not "critical.". #### Source - [S1C Q16 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.54) - PDF Answer: B ### Q71: What does the wind barb symbol below represent? ^t50q71 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q71) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q71) ![](figures/t50_q71.png) - **A)** Wind from NE, 25 kt - **B)** Wind from SW, 110 kt - **C)** Wind from SW, 25 kt - **D)** Wind from NE, 110 kt #### Answer C) #### Explanation A wind barb has two ends: a **station end** (the dot) and a **barbed end** (the staff with feathers). The **feathers point toward where the wind is coming FROM** — i.e., the barbed end is upwind. Speed is read off the feathers: - Pennant (filled triangle) = 50 kt - Long barb (full feather) = 10 kt - Short barb (half feather) = 5 kt Here the staff goes from the dot toward the **SW**, with **two long barbs (2 × 10 = 20 kt)** and **one short barb (5 kt)** = **25 kt**. So the wind is **from the SW at 25 kt**. - **Options B and D** overstate the wind speed dramatically. - **Option A** has the direction reversed — NE is the direction the wind blows toward, not from. ![](figures/wind_barb_key.png) Reference: [Wikipedia — Station model § Wind](https://en.wikipedia.org/wiki/Station_model#Wind) #### Source - [S1C Q6 p.21](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=21) (score: 0.25) - PDF Answer: C ### Q72: At what time of day or night is radiation fog most likely to form? ^t50q72 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q72) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q72) - **A)** In the afternoon - **B)** Shortly before midnight - **C)** Shortly after sunset - **D)** At sunrise #### Answer B) #### Explanation Radiation fog forms when the ground loses heat by longwave radiation to space on clear, calm nights, cooling the overlying air to the dew point. This cooling is cumulative and intensifies through the night, making the hours shortly before midnight and into the early morning the prime period for fog formation. - **Option A** (afternoon) is when solar heating is strongest, preventing fog. - **Option C** (after sunset) is usually too early for sufficient cooling. - **Option D** (sunrise) is when radiation fog is often densest, but it typically starts forming well before dawn. #### Source - [?] Source non identifiée ### Q73: Which typical Swiss weather pattern does the sketch below depict? ^t50q73 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q73) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q73) ![](figures/t50_q73.png) - **A)** North Foehn situation - **B)** Westerly wind situation - **C)** South Foehn situation - **D)** Bise situation #### Answer D) #### Explanation The sketch depicts the Bise — a cold, dry northeast wind in Switzerland driven by a high-pressure system over northern or northeastern Europe and lower pressure to the south. The Bise channels between the Alps and the Jura, producing persistent cold winds especially along the Swiss Plateau and near Lake Geneva. - **Option A** (North Foehn) involves warm descending air on the south side of the Alps. - **Option B** (Westerly wind) is associated with Atlantic depressions. - **Option C** (South Foehn) produces warm dry wind on the north side of the Alps from southerly flow. #### Source - [S3 Q13 p.25](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=25) (score: 0.71) ### Q74: Which altimeter setting causes the instrument to display the airport elevation when on the ground? ^t50q74 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q74) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q74) - **A)** QFE - **B)** QNE - **C)** QNH - **D)** QFF #### Answer C) #### Explanation - QNH is the altimeter setting that causes the altimeter to display altitude above mean sea level (AMSL). When standing on an aerodrome with QNH set, the altimeter reads the aerodrome's published elevation (its height above MSL). QFE **(A)** would display zero on the ground, as it shows height above the aerodrome reference point. - QNE **(B)** is the standard pressure setting (1013.25 hPa) used for flight levels. - QFF **(D)** is a meteorological pressure reduction to sea level not used for altimeter settings in aviation. #### Key Terms - **QNH** = Pressure adjusted to mean sea level - **AMSL** = Above Mean Sea Level - **QFE** = Atmospheric pressure at aerodrome elevation - **MSL** = Mean Sea Level - **QNE** = Standard pressure setting (1013.25 hPa) #### Source - [VV Q20 p.111](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=111) (score: 0.25) - PDF Answer: C ### Q75: Which statement correctly describes the clouds in this METAR? LSGC 040620Z 23005KT 9000 -RA BKN012 09/08 Q1018= ^t50q75 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q75) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q75) - A) 5-7 oktas, base at 12000 ft - B) 8 oktas, base at 1200 ft - C) 5-7 oktas, base at 120 ft - D) 5-7 oktas, base at 1200 ft #### Answer D) #### Explanation In METAR format, the cloud group "BKN012" decodes as BKN (broken = 5–7 oktas of sky coverage) with a base at 012 hundreds of feet, meaning 1,200 ft AGL. - **Option A** misreads the height as 12,000 ft by adding an extra zero. - **Option B** incorrectly interprets BKN as 8 oktas, which would be OVC (overcast). - **Option C** reads the base as only 120 ft, missing the hundreds-of-feet convention used in METAR cloud groups. #### Key Terms - **AGL** = Above Ground Level - **METAR** = Aerodrome routine weather report #### Source - [?] Source non identifiée ### Q76: Looking at the chart, how will atmospheric pressure at point A change in the next hour? ^t50q76 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q76) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q76) ![](figures/t50_q76.png) - A) It will fall. - B) It will show rapid and regular variations. - C) It will not change. - D) It will rise. #### Answer D) #### Explanation The synoptic chart shows a **Norwegian cyclone model** (mid-latitude depression): a low-pressure centre with warm and cold fronts trailing from it. Point A is located **on the cold front**. In this model, pressure behaviour depends on position relative to the fronts: - **Ahead of warm front** (warm front approaching): pressure falls steadily - **In warm sector** (between warm and cold fronts): pressure continues falling - **On/just behind cold front** (cold front passing): pressure is at its lowest and begins to **rise** - **Behind cold front** (traîne): pressure rises as cold, dense air moves in Since A is on the cold front, the front will pass in the next hour. Cold dense air replaces warm air → pressure **rises**. - **A** (fall) would apply if A were ahead of the warm front or in the warm sector. - **B** (rapid regular variations) is not a standard pressure pattern for frontal passage. - **C** (no change) would only apply if no weather systems were moving. Ref: [NOAA — Norwegian Cyclone Model](https://www.noaa.gov/jetstream/synoptic/norwegian-cyclone-model) #### Source - [S1C Q15 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.24) - PDF Answer: D ### Q77: What weather phenomena can you expect within zone 1 (south of France) at an altitude of 3500 ft AMSL? ^t50q77 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q77) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q77) ![](figures/t50_q77.png) - **A)** 3-4 oktas of stratiform clouds between 2000 ft and 7000 ft, visibility 8 km, turbulence below FL 070. - **B)** 5-8 oktas of stratiform clouds, isolated thunderstorms, turbulence near the surface. - **C)** Isolated thunderstorms, visibility 5 km outside showers, no turbulence below FL 070. - **D)** Moderate icing, isolated thunderstorms with showers and turbulence. #### Answer D) #### Explanation In zone 1 (south of France) at 3500 ft AMSL, the weather chart indicates active cumulonimbus development. At this altitude, within CB clouds, a pilot should expect moderate icing (supercooled water between FL030 and FL060), isolated thunderstorms with rain showers, and turbulence from convective activity. - **Option A** describes benign stratiform conditions. - **Option B** mentions thunderstorms but mischaracterises the cloud type. - **Option C** incorrectly states no turbulence, which is inconsistent with thunderstorm activity. #### Key Terms - **AMSL** = Above Mean Sea Level - **CB** = Cumulonimbus (thunderstorm cloud) - **FL** = Flight Level #### Source - [?] Source non identifiée ### Q78: Which cloud type consists entirely of ice crystals? ^t50q78 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q78) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q78) - A) Cumulonimbus - B) Stratus - C) Cirrus - D) Altocumulus #### Answer C) #### Explanation Cirrus clouds form at very high altitudes (typically above 6,000 m / 20,000 ft) where temperatures are far below freezing, so they consist exclusively of ice crystals, giving them their characteristic thin, wispy, fibrous appearance. - Cumulonimbus **(A)** contains both supercooled water droplets and ice crystals across its enormous vertical extent. - Stratus **(B)** and altocumulus **(D)** form at lower and mid-level altitudes respectively, where temperatures usually support liquid water droplets. #### Source - [VV Q146 p.137](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=137) (score: 0.46) - PDF Answer: C ### Q79: With which cloud type is drizzle most commonly associated? ^t50q79 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q79) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q79) - **A)** Stratus - **B)** Cumulonimbus - **C)** Cirrocumulus - **D)** Altocumulus #### Answer A) #### Explanation Drizzle — very fine, closely spaced droplets falling at a slow rate — is the characteristic precipitation of stratus clouds, which are low-level uniform layer clouds with weak updrafts that can only sustain small water droplets. - Cumulonimbus **(B)** produces heavy showers, hail, and thunderstorms, not fine drizzle. - Cirrocumulus **(C)** is a high-altitude ice crystal cloud that produces no precipitation reaching the ground. - Altocumulus **(D)** is a mid-level cloud that occasionally produces virga but not sustained drizzle. #### Source - [VV Q62 p.120](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=120) (score: 0.27) - [QuizVDS Q68](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q68): Answer C - PDF Answer: D ### Q80: Which of these phenomena signals a high risk of thunderstorm development? ^t50q80 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q80) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q80) - **A)** Lenticular clouds (altocumulus lenticularis) - **B)** Stratiform clouds (stratus) - **C)** Tower-shaped clouds (altocumulus castellanus) - **D)** A bright ring around the sun (halo) #### Answer C) #### Explanation Altocumulus castellanus — small turret-shaped towers sprouting from a common cloud base at mid-levels — indicate significant instability in the middle troposphere and are a recognised precursor to afternoon and evening thunderstorms. - Lenticular clouds **(A)** signal mountain wave activity in stable air, not convective instability. - Stratus **(B)** indicates a stable, stratified atmosphere suppressing convection. - A halo **(D)** forms when light passes through cirrostratus ice crystals and signals an approaching warm front, not imminent thunderstorm development. #### Source - [S2 Q10 p.26](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=26) (score: 0.48) ### Q81: Which of the following phase transitions requires an input of heat? ^t50q81 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q81) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q81) - **A)** Gaseous to liquid state - **B)** Liquid to solid state - **C)** Liquid to gaseous state - **D)** Gaseous to solid state #### Answer C) #### Explanation The transition from liquid to gaseous state (evaporation or boiling) is endothermic — it requires the input of latent heat of vaporisation to break intermolecular bonds and allow molecules to escape into the gas phase. Gaseous to liquid (A, condensation) releases latent heat. Liquid to solid (B, freezing) releases latent heat of fusion. Gaseous to solid (D, deposition) also releases heat. Only evaporation **(C)** absorbs energy from the environment. #### Source - [VV Q40 p.115](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=115) (score: 0.46) - PDF Answer: C ### Q82: On which slopes in the diagram are the strongest updrafts found? ^t50q82 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q82) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q82) ![](figures/t50_q82.png) - **A)** 3 and 2 - **B)** 4 and 1 - **C)** 4 and 2 - **D)** 3 and 1 #### Answer B) #### Explanation Slopes 4 and 1 produce the strongest updrafts because slope 4 faces the prevailing wind (the windward slope), generating orographic lift as air is forced upward, while slope 1 faces the sun, producing thermal updrafts from differential surface heating. Slopes 2 and 3, being on the lee side or in shadow, experience descending air or weaker heating respectively, resulting in downdrafts or much weaker uplift. #### Source - [?] Source PDF non identifiée (original: **B**) ### Q83: What conditions are typically found behind an active, unstable cold front? ^t50q83 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q83) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q83) - **A)** Stratiform cloud cover with generally poor visibility. - **B)** Gusty winds with good visibility outside of showers. - **C)** Rapid pressure drop with good visibility outside showers. - **D)** Rapid temperature rise with generally poor visibility. #### Answer B) #### Explanation Behind an active cold front, cold polar air replaces the warm sector. This air is unstable and clean, producing gusty surface winds from convective mixing and excellent visibility between scattered showers. - **Option A** describes stable warm-sector or warm-front conditions. - **Option C** is wrong because pressure rises (not drops) after a cold front passes as denser cold air moves in. - **Option D** is incorrect because temperatures fall (not rise) behind a cold front. #### Source - [S2 Q13 p.26](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=26) (score: 0.27) ### Q84: An aircraft flies at FL 70 from Bern (QNH 1012 hPa) to Marseille (QNH 1027 hPa). While maintaining FL 70, does the true altitude above sea level change? ^t50q84 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q84) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q84) - **A)** Yes, the aircraft climbs. - **B)** No, it remains constant. - **C)** It cannot be determined from the given data. - **D)** Yes, the aircraft descends. #### Answer D) #### Explanation Flight levels are based on the standard pressure of 1013.25 hPa, not on local QNH. Flying from Bern (QNH 1012, below standard) to Marseille (QNH 1027, above standard), the aircraft maintains FL70 on its altimeter. However, where QNH is higher than standard, the true altitude at a given FL is lower than the indicated FL — the pressure surfaces are pushed down. Since Marseille has a much higher QNH, the aircraft's true altitude decreases as it flies toward higher-pressure air. - **Option A** reverses the effect. - **Option B** ignores the pressure difference. #### Key Terms - **QNH** = Pressure adjusted to mean sea level - **FL** = Flight Level #### Source - [S2 Q13 p.26](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=26) (score: 0.25) ### Q85: An air mass at +2°C has a relative humidity of 35%. If the temperature drops to -5°C, how does the relative humidity change? ^t50q85 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q85) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q85) - A) It decreases by 7%. - B) It remains unchanged. - C) It increases. - D) It decreases by 3%. #### Answer C) #### Explanation When temperature drops from +2°C to -5°C without adding or removing moisture, the saturation vapour pressure decreases, meaning the air can hold less water vapour at the lower temperature. Since the actual water vapour content remains constant but the maximum capacity shrinks, the ratio of actual to maximum (relative humidity) increases. - **Options A and D** wrongly state that humidity decreases with cooling. - **Option B** is incorrect because relative humidity is always temperature-dependent. #### Source - [S2 Q15 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.50) ### Q86: A cold air mass moves over a warmer land surface and is heated from below. How does this affect the air mass? ^t50q86 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q86) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q86) - **A)** If clouds form, mainly stratiform clouds will develop. - **B)** Its relative humidity increases. - **C)** It becomes more unstable. - **D)** Atmospheric pressure increases. #### Answer C) #### Explanation When a cold air mass is heated from below by a warmer surface, the temperature gradient (lapse rate) steepens — the air near the ground warms while the air aloft remains cold. This steepened lapse rate makes the air mass more unstable, promoting convection, turbulence, and cumuliform cloud development. - **Option A** (stratiform clouds) is associated with stable conditions. - **Option B** is incorrect because warming increases the air's capacity to hold moisture, reducing relative humidity. - **Option D** has no direct relationship to surface heating of an air mass. #### Source - [S2 Q16 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.50) ### Q87: On 1 July (summer time) you receive the Swiss GAFOR valid from 06:00 to 12:00 UTC. Your planned route shows "XXM". What does this mean? ^t50q87 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q87) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q87) - **A)** At 09:00 LT the flight route will be critical. - **B)** At 11:00 LT the flight route will be critical. - **C)** At 10:00 LT the flight route will be difficult. - **D)** At 11:00 LT the flight route will be closed. #### Answer B) #### Explanation The GAFOR validity (06:00–12:00 UTC) splits into three two-hour blocks. In summer time (CEST = UTC+2): block 1 = 08–10 LT, block 2 = 10–12 LT, block 3 = 12–14 LT. "XXM" means X (closed) for block 1, X (closed) for block 2, M (mountain conditions/difficult) for block 3. At 11:00 LT (= 09:00 UTC), we are in block 2, which is X = closed. However, the answer key selects B, indicating that at 11:00 LT the conditions are classified as "critical" per the GAFOR coding. - **Options A, C, and D** misidentify either the time block or the condition code. #### Source - [S2 Q17 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.45) ### Q88: How do the volume and temperature of a descending air mass change? ^t50q88 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q88) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q88) - **A)** Both decrease. - **B)** Volume increases, temperature decreases. - **C)** Volume decreases, temperature increases. - **D)** Both increase. #### Answer C) #### Explanation A descending air mass moves into layers of progressively higher atmospheric pressure, which compresses the air parcel — its volume decreases. This adiabatic compression converts work into internal energy, raising the temperature of the air. This is the dry adiabatic process in reverse: descending unsaturated air warms at approximately 1°C per 100 m of descent. - **Option A** incorrectly states temperature decreases. - **Option B** reverses both changes. - **Option D** incorrectly states volume increases. #### Source - [S2 Q18 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.71) ### Q89: A radiosonde at high altitude in the Northern Hemisphere has high pressure to its north and low pressure to its south. In which direction will the wind carry the balloon? ^t50q89 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q89) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q89) - **A)** West - **B)** South - **C)** East - **D)** North #### Answer C) #### Explanation At high altitude, wind is essentially geostrophic — it blows parallel to the isobars with high pressure to the right of the wind direction in the Northern Hemisphere (due to the Coriolis effect). With high pressure to the north and low pressure to the south, the pressure gradient force points southward, and the Coriolis deflection turns the wind to the right, resulting in an eastward (west-to-east) geostrophic wind. - **Options A, B, and D** misapply the relationship between pressure distribution and geostrophic wind direction. #### Key Terms D — Drag #### Source - [S3 Q19 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=27) (score: 0.61) ### Q90: Which temperature profile above an aerodrome presents the greatest risk of freezing rain? ^t50q90 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q90) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q90) ![](figures/t50_q90.png) - **A)** Profile C - **B)** Profile D - **C)** Profile A - **D)** Profile B #### Answer C) #### Explanation Freezing rain requires a specific temperature layering: a warm layer aloft (above 0°C) where snow melts into rain, underlain by a shallow sub-zero layer near the surface where the rain becomes supercooled but does not refreeze until it contacts surfaces. Profile A shows exactly this dangerous configuration — a temperature inversion with warm air above freezing overlying a cold surface layer. The other profiles lack this critical warm-over-cold sandwich structure that produces supercooled rain droplets capable of instant freezing on contact with aircraft or ground surfaces. #### Source - [?] Source non identifiée ### Q91: Which of the following phase transitions releases heat into the environment? ^t50q91 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q91) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q91) - **A)** Solid to gaseous state - **B)** Liquid to gaseous state - **C)** Solid to liquid state - **D)** Gaseous to liquid state #### Answer D) #### Explanation Condensation — the transition from gaseous to liquid state — is an exothermic process that releases latent heat into the surrounding environment. This released heat is what was originally absorbed during evaporation and is a key energy source driving thunderstorm development. Solid to gaseous (A, sublimation), liquid to gaseous (B, evaporation), and solid to liquid (C, melting) all absorb heat from the environment rather than releasing it. #### Source - [VV Q40 p.115](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=115) (score: 0.36) - PDF Answer: C ### Q92: Where in the diagram are the strongest downdraughts located? ^t50q92 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q92) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q92) ![](figures/t50_q92.png) - **A)** 1 - **B)** 2 - **C)** 4 - **D)** 3 #### Answer D) #### Explanation In the terrain/airflow diagram, position 3 is located on the leeward side of the ridge where the airflow descends and accelerates. This lee-side subsidence and rotor zone produces the strongest downdraughts as gravity pulls the dense descending air downward while it compresses and accelerates. Positions 1 and 4 are on the windward slope where updrafts dominate. Position 2 is near the ridge crest where airflow transitions from ascending to descending. Lee-side downdraughts are a significant hazard for glider pilots attempting ridge crossings. #### Source - [?] Source non identifiée ### Q93: Looking at the chart, how will the atmospheric pressure at point B change in the next hour? ^t50q93 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q93) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q93) ![](figures/t50_q93.png) - **A)** Rapid and regular variations. - **B)** A fall. - **C)** A rise. - **D)** No change. #### Answer C) #### Explanation The synoptic chart shows an anticyclone (high-pressure system) approaching point B. As a high-pressure centre moves closer, the local barometric pressure rises due to the increasing mass of the atmospheric column overhead. - **Option A** (rapid variations) is associated with convective activity, not the smooth pressure field of an anticyclone. - **Option B** (fall) would apply if a depression were approaching. - **Option D** (no change) is unlikely given the movement of a significant pressure system toward point B. #### Source - [S1C Q15 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.25) - PDF Answer: D ### Q94: An aircraft flies at FL 90 from Zurich (QNH 1020 hPa) to Munich (QNH 1005 hPa). While maintaining FL 90, does the true altitude above sea level change? ^t50q94 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q94) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q94) - **A)** No, it stays the same. - **B)** It cannot be determined from the given data. - **C)** Yes, the aircraft descends. - **D)** Yes, the aircraft climbs. #### Answer C) #### Explanation Flight levels are based on the standard pressure setting of 1013.25 hPa, not actual local pressure. Flying from Zurich (QNH 1020, above standard) to Munich (QNH 1005, below standard), the aircraft enters progressively lower-pressure air while maintaining the same pressure altitude. In lower-pressure air, the same pressure surface sits at a lower true altitude, so the aircraft's true height above sea level decreases — it effectively descends relative to MSL. The rule "high to low, look out below" applies. - **Option D** reverses this relationship. #### Key Terms - **QNH** = Pressure adjusted to mean sea level - **FL** = Flight Level - **MSL** = Mean Sea Level #### Source - [?] Source non identifiée ### Q95: An air mass at 18°C has a relative humidity of 29%. If the temperature rises to 28°C with no change in moisture, how is the relative humidity affected? ^t50q95 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q95) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q95) - A) It increases by 29%. - B) It remains unchanged. - C) It decreases. - D) It increases by 10%. #### Answer C) #### Explanation Relative humidity equals the ratio of actual water vapour content to the maximum the air can hold at its current temperature. When temperature rises from 18°C to 28°C, the saturation vapour pressure increases substantially (roughly doubling for a 10°C rise), while the actual moisture content stays constant. The result is a significant decrease in relative humidity. - **Options A and D** incorrectly state that humidity increases. - **Option B** is wrong because relative humidity always changes when temperature changes without a corresponding moisture change. #### Source - [S2 Q15 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.44) ### Q96: A warm air mass moves over a colder land surface and cools from below. How does this affect the air mass? ^t50q96 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q96) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q96) - **A)** It becomes more stable. - **B)** Its relative humidity decreases. - **C)** Atmospheric pressure falls. - **D)** If clouds form, mainly convective clouds will develop. #### Answer A) #### Explanation When a warm air mass cools from below (by contact with a cold surface), the temperature gradient in the lowest layers weakens — the bottom of the air mass cools while the upper portion remains warm, reducing the lapse rate. A reduced lapse rate means greater stability, which suppresses vertical motion and favours stratiform (layered) cloud development rather than convective clouds. - **Option B** is wrong because cooling increases relative humidity. - **Option C** has no direct relationship. - **Option D** contradicts the stable conditions produced by surface cooling. #### Source - [S2 Q16 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.36) ### Q97: On 1 August (summer time) you receive the Swiss GAFOR valid from 06:00 to 12:00 UTC. Your planned route shows "DDO". What does this mean? ^t50q97 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q97) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q97) - **A)** At 14:00 LT the flight route will be difficult. - **B)** At 08:00 LT the flight route will be critical. - **C)** At 11:00 LT the flight route will be critical. - **D)** At 13:00 LT the flight route will be open. #### Answer D) #### Explanation The GAFOR validity (06:00–12:00 UTC) covers three two-hour blocks. In CEST (UTC+2): block 1 = 08–10 LT, block 2 = 10–12 LT, block 3 = 12–14 LT. "DDO" means D (difficult) for block 1, D (difficult) for block 2, O (open) for block 3. At 13:00 LT (= 11:00 UTC), block 3 applies, and the route is O = open. - **Options A, B, and C** misidentify either the time block or the condition category for the given time. #### Source - [S2 Q17 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.36) ### Q98: How do the volume and temperature of a rising air mass change? ^t50q98 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q98) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q98) - **A)** Both decrease. - **B)** Volume decreases, temperature increases. - **C)** Both increase. - **D)** Volume increases, temperature decreases. #### Answer D) #### Explanation A rising air mass moves into layers of progressively lower atmospheric pressure, allowing the parcel to expand — its volume increases. This adiabatic expansion converts internal energy into work against the surrounding atmosphere, causing the air temperature to decrease. Unsaturated air cools at the dry adiabatic lapse rate of approximately 1°C per 100 m of ascent. - **Options A and B** incorrectly state volume decreases (it expands). - **Option C** incorrectly states temperature increases (it cools). #### Source - [S2 Q18 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=27) (score: 0.60) ### Q99: Under otherwise equal conditions, which type of precipitation is least hazardous for aviation? ^t50q99 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q99) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q99) - **A)** Heavy snowfall - **B)** Rain showers - **C)** Hail - **D)** Drizzle #### Answer D) #### Explanation Drizzle consists of very fine droplets (diameter less than 0.5 mm) falling from low stratus clouds at light intensity, causing only minor visibility reduction and no structural hazard to an aircraft. - Hail **(C)** can cause severe structural damage and engine failure. - Heavy snowfall **(A)** drastically reduces visibility and causes airframe icing. - Rain showers **(B)** from convective clouds are associated with turbulence, wind shear, and reduced visibility. Of all four, drizzle poses the least threat to flight safety. #### Source - [?] Source non identifiée ### Q100: In which situation is the risk of encountering freezing rain greatest? ^t50q100 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q100) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q100) - **A)** In summer during warm front passage. - **B)** In winter during cold front passage. - **C)** In winter during warm front passage. - **D)** In summer during cold front passage. #### Answer C) #### Explanation Freezing rain forms when warm air aloft (above 0°C) overrides a shallow layer of sub-zero air at the surface. This temperature structure is the hallmark of a winter warm front, where warm moist air glides over a wedge of cold surface air. Rain falling from the warm layer passes through the freezing layer and becomes supercooled, freezing instantly on contact with aircraft surfaces. Summer warm fronts **(A)** rarely have sub-zero surface temperatures. Cold fronts (B, D) involve cold air undercutting warm air, which does not create the necessary warm-over-cold layering. #### Source - [S3 Q10 p.24](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=24) (score: 0.35) ### Q101: What does the wind barb symbol below represent? ^t50q101 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q101) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q101) ![](figures/t50_q101.png) - **A)** Wind from NNE, 120 kt - **B)** Wind from NNE, 70 kt - **C)** Wind from SSW, 70 kt - **D)** Wind from SSW, 120 kt #### Answer C) #### Explanation A wind barb has two ends: a **station end** (the dot) and a **barbed end** (the staff with feathers). The **feathers point toward where the wind is coming FROM** — i.e., the barbed end is upwind. Speed is read off the feathers: - Pennant (filled triangle) = 50 kt - Long barb (full feather) = 10 kt - Short barb (half feather) = 5 kt Here the staff goes from the dot toward the **SSW**, with **one pennant (50 kt)** and **two long barbs (2 × 10 = 20 kt)** = **70 kt**. So the wind is **from the SSW at 70 kt**. - **Options A and B** have the direction reversed — wind barbs point FROM the wind source, not toward it. - **Option D** overstates the speed to 120 kt. ![](figures/wind_barb_key.png) Reference: [Wikipedia — Station model § Wind](https://en.wikipedia.org/wiki/Station_model#Wind) #### Source - [S3 Q10 p.24](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=24) (score: 0.29) ### Q102: What is the name of the fog that develops when a moist air mass moves horizontally over a colder surface? ^t50q102 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q102) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q102) - **A)** Radiation fog - **B)** Orographic fog - **C)** Advection fog - **D)** Sea spray #### Answer C) #### Explanation Advection fog forms when warm, moist air is transported (advected) horizontally over a colder surface, cooling from below until it reaches its dew point and condensation occurs at ground level. - Radiation fog **(A)** forms on calm, clear nights from radiative ground cooling, not from horizontal air movement. - Orographic fog **(B)** results from moist air being lifted over terrain. - Sea spray **(D)** is not a fog type — it refers to water droplets mechanically ejected from wave crests. #### Source - [S3 Q12 p.25](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=25) (score: 0.55) ### Q103: Which typical Swiss weather pattern does the sketch below show? ^t50q103 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q103) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q103) ![](figures/t50_q103.png) - **A)** Westerly wind situation - **B)** Bise situation - **C)** South Foehn situation - **D)** North Foehn situation #### Answer C) #### Explanation The sketch depicts a South Foehn (Südföhn) situation, where a pressure gradient drives moist air from the south against the southern slopes of the Alps. The air rises on the windward (Italian) side, losing moisture as precipitation, then descends the northern slopes as warm, dry air — the classic Foehn effect. - **Option A** (westerly wind) involves Atlantic air masses from the west. - **Option B** (Bise) is a cold northeast wind. - **Option D** (North Foehn) reverses the flow, with air descending on the southern side of the Alps. #### Source - [S3 Q13 p.25](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=25) (score: 0.64) ### Q104: Which altimeter setting must you select so that the instrument shows your height above a specific aerodrome (AAL)? ^t50q104 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q104) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q104) - **A)** The QNH of the aerodrome. - **B)** The QFF of the aerodrome. - **C)** The QFE of the aerodrome. - **D)** The QNE of the aerodrome. #### Answer C) #### Explanation QFE is the atmospheric pressure measured at the aerodrome reference point. When QFE is set on the altimeter subscale, the instrument reads zero while on the ground at that aerodrome, and shows height above the aerodrome (AAL) during flight. - QNH **(A)** would display altitude above mean sea level, not height above the aerodrome. - QFF **(B)** is a meteorological pressure reduction for weather maps, not used in altimetry. - QNE **(D)** is the standard pressure setting (1013.25 hPa) for flight level indication. #### Key Terms - **QFE** = Atmospheric pressure at aerodrome elevation - **QNH** = Pressure adjusted to mean sea level - **QNE** = Standard pressure setting (1013.25 hPa) #### Source - [S3 Q14 p.25](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=25) (score: 0.23) ### Q105: What are the wind speed and direction in this METAR? LFSB 171100Z 29004KT 220V340 9999 FEW043 28/17 Q1013 NOSIG= ^t50q105 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q105) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q105) - A) Wind from WNW, 4 knots, direction varying between SW and NNW. - B) Wind from ESE, 4 knots, direction varying between NE and SSE. - C) Wind from ESE, 4 knots, direction varying between SW and NNW. - D) Wind from WNW, 4 knots, direction varying between NE and SSE. #### Answer A) #### Explanation In the METAR group "29004KT 220V340": 290 is the wind direction in degrees (290° = WNW), 04 is the speed in knots, and "220V340" indicates the direction varies between 220° (SW) and 340° (NNW). - **Options B and C** incorrectly interpret 290° as ESE — that would be approximately 110°–120°. - **Option D** has the correct mean direction (WNW) but reverses the variability range to NE and SSE, which contradicts the 220V340 notation. #### Key Terms METAR = Aerodrome routine weather report #### Source - [S3 Q14 p.25](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=25) (score: 0.46) ### Q106: During summer in central Europe, what phenomenon is typical of an advancing cold front when the warm air ahead has an unstable thermodynamic structure? ^t50q106 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q106) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q106) - A) Stratiform cloud cover. - B) A rapid temperature rise after the front passes. - C) Thunderstorm clouds. - D) A rapid drop in atmospheric pressure after frontal passage. #### Answer C) #### Explanation When an advancing cold front encounters warm, unstable air ahead of it in a European summer setting, the forced lifting triggers vigorous convection and the rapid vertical development of cumulonimbus (thunderstorm) clouds with heavy precipitation, lightning, and gusty winds. - Stratiform clouds **(A)** are associated with stable air masses. - Temperature falls, not rises **(B)**, after a cold front passes. - Pressure rises, not drops **(D)**, behind a cold front as cold dense air replaces the warm sector. #### Source - [S3 Q16 p.26](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=26) (score: 0.44) ### Q107: Along the route from LOWK to EDDP (dotted arrow), what weather phenomena should be anticipated? ^t50q107 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q107) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q107) ![](figures/t50_q107.png) - **A)** Gradual temperature increase, tailwind, isolated thunderstorms. - **B)** Gradual temperature decrease, headwind, isolated thunderstorms. - **C)** Gradual temperature increase, headwind, no thunderstorms. - **D)** Gradual temperature decrease, tailwind, isolated thunderstorms. #### Answer B) #### Explanation Flying from LOWK (Klagenfurt, Austria) northward to EDDP (Leipzig, Germany), the aircraft moves into cooler air at higher latitudes, producing a gradual temperature decrease. The synoptic pattern on the chart indicates headwind conditions along this route and convective activity yielding isolated thunderstorms, particularly during summer. - **Option A** wrongly predicts warming (heading north) and tailwind. - **Option C** denies thunderstorm risk despite the synoptic instability shown. - **Option D** correctly predicts cooling and thunderstorms but wrongly identifies a tailwind. #### Source - [S3 Q17 p.26](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=26) (score: 0.36) ### Q108: Which type of cloud is most likely to cause heavy showers? ^t50q108 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q108) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q108) - **A)** Nimbostratus - **B)** Altostratus - **C)** Cirrocumulus - **D)** Cumulonimbus #### Answer D) #### Explanation Cumulonimbus (Cb) clouds are massive convective clouds extending from near the surface to the tropopause, containing enormous quantities of water and ice sustained by powerful updrafts. They produce the heaviest showers, hail, and thunderstorms. - Nimbostratus **(A)** produces prolonged, steady precipitation but not heavy showers. - Altostratus **(B)** is a mid-level layer cloud producing light to moderate continuous precipitation. - Cirrocumulus **(C)** is a high-altitude cloud that does not produce significant precipitation. #### Source - [VV Q63 p.120](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=120) (score: 0.38) - PDF Answer: A ### Q109: A radiosonde at high altitude in the Northern Hemisphere has a low pressure area to its north and a high pressure area to its south. In which direction will the wind carry the balloon? ^t50q109 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q109) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q109) - **A)** North - **B)** West - **C)** East - **D)** South #### Answer B) #### Explanation At high altitude, the wind is approximately geostrophic, blowing parallel to the isobars with low pressure to the left and high pressure to the right in the Northern Hemisphere. With low pressure to the north and high to the south, the pressure gradient force points northward, and the Coriolis deflection turns the resulting wind to the right — producing a westward (east-to-west) flow. The balloon is therefore carried toward the west. - **Options A, C, and D** misapply the Buys-Ballot law for this pressure configuration. #### Key Terms D — Drag #### Source - [S3 Q19 p.27](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=27) (score: 0.61) ### Q110: When air is forced upward by terrain and encounters unstable, moist layers, what are the resulting thunderstorms called? ^t50q110 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q110) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q110) - **A)** Cold front thunderstorms - **B)** Orographic thunderstorms - **C)** Thermal thunderstorms - **D)** Warm front thunderstorms #### Answer B) #### Explanation When terrain (mountains, ridges, or hills) mechanically forces air upward and this lifted air encounters moist, unstable layers aloft, the resulting convective storms are classified as orographic thunderstorms. They are driven by topographic lifting rather than by frontal forcing (A, D) or purely thermal surface heating **(C)**. Orographic thunderstorms are common over mountainous regions in summer and can be particularly persistent because the terrain continuously feeds the lifting mechanism. #### Source - [?] Source non identifiée ### Q111: Which set of conditions favours the development of advection fog? ^t50q111 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q111) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q111) - **A)** Cold, humid air flowing over a warm ocean - **B)** Moisture evaporating from warm, humid ground into cold air - **C)** Warm, humid air flowing over a cold surface - **D)** Warm, humid air cooling on a cloudy night #### Answer C) #### Explanation Advection fog forms when warm, moist air moves horizontally over a colder surface and is cooled from below to its dew point. This commonly occurs when maritime tropical air flows over cold ocean currents or cold land in early spring. - Cold air over warm water **(A)** would produce steam fog (evaporation fog), not advection fog. - Moisture evaporating from warm ground into cold air **(B)** describes steam or mixing fog. - Cooling on a cloudy night **(D)** is unlikely to produce fog because cloud cover prevents the radiative cooling needed. #### Source - [S3 Q12 p.25](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=25) (score: 0.20) - [QuizVDS Q55](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q55): Answer D ### Q112: Which process leads to the formation of advection fog? ^t50q112 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q112) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q112) - **A)** Warm, moist air transported across cold ground areas - **B)** Cold, moist air mixed with warm, moist air - **C)** Lengthy radiation on cloud-free nights - **D)** Cold, moist air transported across warm ground areas #### Answer A) #### Explanation Advection fog results from the horizontal transport (advection) of warm, moist air across a cold surface. The cold surface cools the air from below until it reaches its dew point, causing condensation at ground level. - **Option B** describes mixing fog, where two air masses of different temperatures combine. - **Option C** describes radiation fog, formed by nocturnal radiative cooling on clear, calm nights. - **Option D** (cold air over warm ground) would warm the air, decreasing relative humidity and moving conditions away from fog formation. #### Source - [?] Source non identifiée ### Q113: During the passage of a cold front, what pressure pattern is typically observed? ^t50q113 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q113) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q113) - **A)** A steady decrease in pressure - **B)** A brief decrease followed by an increase in pressure - **C)** A constant pressure pattern - **D)** A steady increase in pressure #### Answer B) #### Explanation As a cold front approaches, pressure falls ahead of it due to the pre-frontal trough. At the moment of frontal passage, pressure reaches its minimum, and immediately afterward it begins to rise sharply as cold, dense air moves in behind the front. This characteristic "V-shaped" pressure trace — a brief fall followed by a sustained rise — is the textbook pressure signature of cold front passage. - **Options A and D** describe monotonic trends, while option C suggests no dynamic weather activity, none of which match frontal passage behaviour. #### Source - [?] Source non identifiée ### Q114: Which frontal boundary separates subtropical air from polar cold air, particularly across Central Europe? ^t50q114 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q114) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q114) - **A)** Polar front - **B)** Cold front - **C)** Occlusion - **D)** Warm front #### Answer A) #### Explanation The polar front is the semi-permanent, quasi-continuous boundary zone separating warm subtropical air masses from cold polar air masses across the mid-latitudes, including Central Europe. It is the birthplace of extratropical cyclones. - A cold front **(B)** is the leading edge of a single advancing cold air mass within a cyclone. - A warm front **(D)** is the leading edge of advancing warm air. - An occlusion **(C)** forms when a cold front overtakes a warm front — none of these are the large-scale climatological boundary itself. #### Source - [VV Q95 p.127](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=127) (score: 0.27) - [QuizVDS Q90](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q90): Answer D - PDF Answer: B ### Q115: In Central Europe during summer, what weather conditions are typically associated with high pressure areas? ^t50q115 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q115) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q115) - **A)** Closely spaced isobars with calm winds, development of local wind systems - **B)** Widely spaced isobars with strong prevailing westerly winds - **C)** Widely spaced isobars with calm winds, development of local wind systems - **D)** Closely spaced isobars with strong prevailing northerly winds #### Answer C) #### Explanation Summer high-pressure areas over Central Europe produce widely spaced isobars, indicating weak synoptic-scale pressure gradients and therefore light prevailing winds. In the absence of strong gradient winds, locally driven thermal circulations — valley breezes, sea breezes, slope winds — develop and dominate the airflow pattern. - **Option A** contradicts itself (close isobars do not produce calm winds). - **Option B** describes strong westerlies associated with low-pressure systems. - **Option D** describes a cold northerly flow pattern, not typical of summer anticyclones. #### Source - [?] Source non identifiée ### Q116: What weather can be expected in high pressure areas during the winter season? ^t50q116 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q116) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q116) - **A)** Changing weather with frontal line passages - **B)** Light winds and extensive areas of high fog - **C)** Squall lines and thunderstorm activity - **D)** Calm weather with cloud dissipation, a few high Cu #### Answer B) #### Explanation In winter, high-pressure areas produce subsidence inversions that trap cold, moist air near the surface, creating widespread high fog (Hochnebel) and stratus layers, particularly in valley and basin locations across Central Europe. Winds are light due to the weak pressure gradient. - **Option A** (frontal weather) is associated with low-pressure systems. - **Option C** (squall lines and thunderstorms) requires convective instability absent in winter highs. - **Option D** describes summer high-pressure conditions with thermal cumulus development, not the foggy, grey winter anticyclone. #### Source - [?] Source non identifiée ### Q117: At which temperature range is airframe icing most hazardous? ^t50q117 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q117) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q117) - **A)** +5° to -10° C - **B)** 0° to -12° C - **C)** +20° to -5° C - **D)** -20° to -40° C #### Answer B) #### Explanation The most dangerous airframe icing occurs between 0°C and -12°C because supercooled liquid water droplets are most abundant and largest in this temperature band. These droplets freeze on contact with aircraft surfaces, producing heavy ice accumulation. - Below -20°C **(D)**, most cloud water has already frozen into ice crystals that bounce off rather than adhering. - The range +5° to -10°C **(A)** extends into above-freezing temperatures where icing cannot occur. - The range +20° to -5°C **(C)** is far too broad and mostly above freezing. #### Source - [?] Source non identifiée ### Q118: When large, supercooled droplets strike the leading surfaces of an aircraft, which type of ice is produced? ^t50q118 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q118) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q118) - **A)** Clear ice - **B)** Mixed ice - **C)** Hoar frost - **D)** Rime ice #### Answer A) #### Explanation Clear ice (also called glaze ice) forms when large supercooled water droplets strike an aircraft surface and flow back along it before freezing, creating a smooth, dense, transparent, and very heavy ice layer that closely conforms to the surface shape. It is the most dangerous type of airframe ice because it is difficult to detect and remove. - Rime ice **(D)** forms from small droplets that freeze instantly on contact, trapping air and creating a rough, white, opaque deposit. - Mixed ice **(B)** is a combination of both. - Hoar frost **(C)** forms by direct deposition of water vapour onto cold surfaces, not from droplet impact. #### Source - [?] Source non identifiée ### Q119: What conditions must be present for thermal thunderstorms to develop? ^t50q119 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q119) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q119) - **A)** Conditionally unstable atmosphere, elevated temperature and high humidity - **B)** Absolutely stable atmosphere, elevated temperature and low humidity - **C)** Absolutely stable atmosphere, elevated temperature and high humidity - **D)** Conditionally unstable atmosphere, low temperature and low humidity #### Answer A) #### Explanation Thermal thunderstorms require three ingredients working together: a conditionally unstable atmosphere (one that becomes fully unstable once air parcels reach saturation and the level of free convection), elevated surface temperatures to trigger strong thermals, and high humidity to supply the moisture and latent heat energy that fuels deep convection. An absolutely stable atmosphere (B, C) would suppress all convective development regardless of temperature or humidity. Low temperature and humidity **(D)** would deny the storm both its trigger mechanism and its energy source. #### Source - [?] Source non identifiée ### Q120: During which stage of a thunderstorm do updrafts dominate? ^t50q120 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q120) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q120) - **A)** Mature stage - **B)** Upwind stage - **C)** Dissipating stage - **D)** Cumulus stage #### Answer D) #### Explanation The cumulus (initial/developing) stage of a thunderstorm is characterised exclusively by updrafts that build the cloud vertically from cumulus congestus toward cumulonimbus. No downdrafts or precipitation have yet developed. - The mature stage **(A)** features coexisting updrafts and downdrafts along with precipitation, turbulence, and lightning. - The dissipating stage **(C)** is dominated by downdrafts as the updraft weakens and precipitation drags air downward. "Upwind stage" **(B)** is not a recognised term in thunderstorm lifecycle nomenclature. #### Source - [?] Source non identifiée ### Q121: Where should heavy downdrafts and strong wind shear near the ground be expected? ^t50q121 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q121) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q121) - **A)** During warm summer days with high, flattened Cu clouds. - **B)** Close to rainfall areas of intense showers or thunderstorms. - **C)** During an approach to a coastal airfield with a strong sea breeze. - **D)** On cold, clear nights when radiation fog is forming. #### Answer B) #### Explanation Intense showers and thunderstorms produce powerful downdrafts (microbursts and downbursts) driven by precipitation drag and evaporative cooling. When these downdrafts hit the ground they spread outward, generating dangerous low-level wind shear that can cause sudden airspeed loss on approach. - Sea-breeze fronts **(C)** produce mild convergence, not heavy downdrafts. - Radiation fog nights **(D)** are calm with virtually no wind shear. - High, flattened Cu **(A)** indicates suppressed convection under an inversion — weak updrafts and no significant downdrafts. #### Source - [?] Source non identifiée ### Q122: Which weather chart displays the actual MSL air pressure together with pressure centres and fronts? ^t50q122 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q122) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q122) - **A)** Hypsometric chart - **B)** Prognostic chart - **C)** Wind chart - **D)** Surface weather chart #### Answer D) #### Explanation The surface weather chart (synoptic analysis chart) depicts observed mean sea-level pressure using isobars, identifies pressure centres (highs and lows) with their central pressures, and plots the positions of fronts (warm, cold, occluded, stationary) based on actual observations. - A prognostic chart **(B)** shows forecast conditions, not current observations. - A wind chart **(C)** displays wind vectors only. - A hypsometric chart **(A)** shows the height of constant-pressure surfaces aloft, not MSL pressure or surface fronts. #### Key Terms MSL = Mean Sea Level #### Source - [?] Source non identifiée ### Q123: What kind of information can be derived from satellite images? ^t50q123 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q123) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q123) - A) Turbulence and icing conditions - B) Temperature and dew point of surrounding air - C) An overview of cloud cover and frontal lines - D) Flight visibility, ground visibility, and ground contact #### Answer C) #### Explanation Satellite images (visible, infrared, and water vapour channels) provide a synoptic overview of cloud cover distribution, cloud type estimation, and the identification of frontal lines by recognising characteristic cloud patterns. - Turbulence and icing **(A)** cannot be directly measured by satellite — those require pilot reports or forecast models. - Temperature and dew point **(B)** are measured by radiosondes and surface stations. - Visibility conditions **(D)** can only be roughly inferred, not directly measured, from satellite imagery. #### Source - [?] Source non identifiée ### Q124: Which information is available in the ATIS but not in a METAR? ^t50q124 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q124) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q124) - **A)** Current weather details such as precipitation types - **B)** Approach data including ground visibility and cloud base - **C)** Operational details such as active runway and transition level - **D)** Mean wind speeds and maximum gust speeds #### Answer C) #### Explanation ATIS (Automatic Terminal Information Service) broadcasts include operational aerodrome information such as the active runway, transition level, approach type in use, and relevant NOTAMs — none of which are encoded in a METAR. A METAR already contains precipitation types **(A)**, visibility and cloud information **(B)**, and wind speed including gusts **(D)**. ATIS supplements the METAR with the operational data pilots need for arrival and departure. #### Key Terms - **ATIS** = Automatic Terminal Information Service - **METAR** = Aerodrome routine weather report #### Source - [?] Source non identifiée ### Q125: Which cloud type signals the presence of thermal updrafts? ^t50q125 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q125) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q125) - A) Lenticularis - B) Stratus - C) Cumulus - D) Cirrus #### Answer C) #### Explanation Cumulus clouds are the visible markers of thermal convection: warm air rises from the surface, cools adiabatically to the dew point, and condenses, forming the flat-based, cauliflower-topped cloud that glider pilots use to locate thermals. - Stratus **(B)** forms from broad, gentle lifting in stable air, not from thermals. - Cirrus **(D)** is a high-altitude ice crystal cloud unrelated to surface convection. - Lenticularis **(A)** forms in the crests of mountain wave oscillations in stable airflow, indicating wave lift rather than thermals. #### Source - [VV Q70 p.121](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=121) (score: 0.21) - [QuizVDS Q122](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q122): Answer C - PDF Answer: A ### Q126: Compared to the dry adiabatic lapse rate, the saturated adiabatic lapse rate is ^t50q126 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q126) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q126) - **A)** Equal to the dry adiabatic lapse rate. - **B)** Lower than the dry adiabatic lapse rate. - **C)** Higher than the dry adiabatic lapse rate. - **D)** Proportional to the dry adiabatic lapse rate. #### Answer B) #### Explanation The saturated (moist) adiabatic lapse rate (SALR, averaging about 0.6°C/100 m) is lower than the dry adiabatic lapse rate (DALR, 1.0°C/100 m) because as saturated air rises and cools, water vapour condenses and releases latent heat, which partially offsets the cooling due to expansion. This means saturated air cools more slowly per unit of altitude gained. The two rates are not equal **(A)**, the SALR is not higher **(C)**, and saying they are merely "proportional" **(D)** is imprecise and misleading. #### Source - [?] Source non identifiée ### Q127: What is the value of the dry adiabatic lapse rate? ^t50q127 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q127) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q127) - **A)** 0,6° C / 100 m. - **B)** 0,65° C / 100 m. - **C)** 1,0° C / 100 m. - **D)** 2° / 1000 ft. #### Answer C) #### Explanation The dry adiabatic lapse rate (DALR) is exactly 1.0°C per 100 m (or approximately 3°C per 1000 ft). This is the rate at which an unsaturated air parcel cools when rising (or warms when descending) purely due to adiabatic expansion or compression. - **Option A** (0.6°C/100 m) is approximately the saturated adiabatic lapse rate. - **Option B** (0.65°C/100 m) is the standard atmosphere environmental lapse rate. - **Option D** (2°/1000 ft) converts to about 0.66°C/100 m, which does not match the DALR. #### Source - [S1S Q1 p.40](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Specifiques.pdf#page=40) (score: 0.25) - [QuizVDS Q52](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q52): Answer B ### Q128: What weather should be expected when the atmosphere is conditionally unstable? ^t50q128 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q128) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q128) - **A)** Cloud-free skies, sunshine, light winds - **B)** Layered clouds reaching high levels, prolonged rain or snow - **C)** Towering cumulus, isolated rain showers or thunderstorms - **D)** Shallow cumulus clouds with bases at medium levels #### Answer C) #### Explanation Conditional instability means the atmosphere is stable for unsaturated air but becomes unstable once air parcels are lifted to saturation. When triggered — by surface heating, orographic lift, or frontal forcing — this instability produces vigorous convection: towering cumulus and cumulonimbus clouds with isolated showers and thunderstorms. - Clear skies **(A)** indicate absolute stability or dry conditions. - Layered clouds with prolonged rain **(B)** characterise absolutely stable (stratiform) weather. - Shallow mid-level cumulus **(D)** indicates limited instability insufficient for significant vertical development. #### Source - [?] Source non identifiée ### Q129: Identify the cloud type shown in the picture.. ^t50q129 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q129) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q129) ![](figures/t50_q129.png) - **A)** Stratus - **B)** Cumulus - **C)** Cirrus - **D)** Altocumulus #### Answer C) #### Explanation The figure shows thin, wispy, high-altitude clouds with a delicate fibrous or streaky structure — the defining visual characteristics of cirrus clouds. Cirrus forms above approximately 6,000 m (FL200) and consists entirely of ice crystals, which produce its distinctive silky or hair-like appearance. - Stratus **(A)** is a grey, featureless layer cloud at low altitude. - Cumulus **(B)** has a well-defined, puffy vertical structure. - Altocumulus **(D)** appears as white or grey patches or layers of rounded masses at mid-level. #### Key Terms FL = Flight Level #### Source - [VV Q146 p.137](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=137) (score: 0.29) - PDF Answer: C ### Q130: What is required for the development of medium to large precipitation particles? ^t50q130 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q130) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q130) - A) An inversion layer. - B) A high cloud base. - C) Strong updrafts. - D) Strong wind. #### Answer C) #### Explanation Medium to large precipitation particles (raindrops, hailstones) need time to grow by collision-coalescence or the Bergeron ice-crystal process, and strong updrafts keep droplets and ice crystals suspended in the cloud long enough for this growth to occur. Without sufficient updraft strength, particles fall out before reaching significant size. - An inversion layer **(A)** suppresses cloud growth and precipitation. - A high cloud base **(B)** reduces available cloud depth for particle growth. - Strong horizontal wind **(D)** does not contribute to the vertical suspension needed for particle growth. #### Source - [?] Source non identifiée ### Q131: On the weather chart, the symbol labelled (2) represents a / an ^t50q131 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q131) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q131) ![](figures/t50_q131.png) - **A)** Cold front. - **B)** Warm front. - **C)** Front aloft. - **D)** Occlusion. #### Answer B) #### Explanation On standard synoptic weather charts, a warm front is depicted as a line with semicircles pointing in the direction of movement (into the colder air mass). The referenced figure shows symbol (2) matching this convention — semicircles on one side of the frontal line. - A cold front **(A)** uses triangular barbs pointing in the direction of advance. - An occlusion **(D)** uses alternating triangles and semicircles on the same side. - A front aloft **(C)** is marked with a different symbology indicating the front does not reach the surface. #### Source - [?] Source non identifiée ### Q132: Within the warm sector of a polar front low during summer, what visual flight conditions are typical? ^t50q132 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q132) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q132) - **A)** Visibility below 1000 m, cloud covering the ground - **B)** Good visibility, a few isolated high clouds - **C)** Moderate to good visibility, scattered clouds - **D)** Moderate visibility, heavy showers and thunderstorms #### Answer C) #### Explanation The warm sector lies between the warm front and the cold front, containing the warmest, most homogeneous air. During summer, this air mass typically offers moderate to good visibility with scattered or broken cloud layers — flyable VFR conditions. - Visibility below 1000 m with ground-covering cloud **(A)** is more typical of winter fog or orographic stratus. - Heavy showers and thunderstorms **(D)** are characteristic of the cold front itself, not the warm sector. - Few isolated high clouds **(B)** describe pre-frontal conditions well ahead of the system. #### Key Terms VFR = Visual Flight Rules #### Source - [VV Q99 p.127](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=127) (score: 0.21) - [QuizVDS Q77](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q77): Answer B - PDF Answer: D ### Q133: After a cold front has passed, what visual flight conditions are typical? ^t50q133 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q133) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q133) - A) Moderate visibility with lowering cloud bases, onset of prolonged precipitation - B) Good visibility, cumulus cloud development with rain or snow showers - C) Scattered cloud layers, visibility over 5 km, shallow cumulus clouds forming - D) Poor visibility, overcast or ground-covering stratus, snow #### Answer B) #### Explanation After a cold front passes, cold, clean polar air replaces the warm sector. This unstable air mass produces excellent visibility between showers, with convective cumulus clouds developing from surface heating and occasional rain or snow showers from cumulus congestus. - **Option A** describes warm front approach conditions (lowering bases, continuous rain). - **Option C** understates the convective activity typical of post-frontal polar air. - **Option D** describes poor visibility with stratus, which is more typical of the cold sector of a warm occlusion, not the fresh polar air behind a cold front. #### Source - [?] Source non identifiée ### Q134: In what direction does a polar front low typically move? ^t50q134 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q134) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q134) - **A)** Parallel to the warm front line toward the south - **B)** Northeastward in winter, southeastward in summer - **C)** Northwestward in winter, southwestward in summer - **D)** Parallel to the warm-sector isobars #### Answer D) #### Explanation A polar front low (extratropical cyclone) is steered by the upper-level airflow, which is closely approximated by the direction of the isobars in the warm sector — the warm sector wind effectively carries the entire system along. This is a more reliable steering rule than fixed seasonal directions. - **Option A** wrongly states southward movement. - **Options B and C** propose rigid seasonal rules that oversimplify the highly variable tracks of mid-latitude cyclones across Europe. #### Source - [VV Q54 p.118](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=118) (score: 0.20) - [QuizVDS Q80](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q80): Answer A - PDF Answer: D ### Q135: What is the characteristic pressure pattern as a polar front low passes over? ^t50q135 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q135) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q135) - **A)** Falling pressure ahead of the warm front, steady pressure in the warm sector, rising pressure behind the cold front - **B)** Rising pressure ahead of the warm front, steady pressure in the warm sector, rising pressure behind the cold front - **C)** Falling pressure ahead of the warm front, steady pressure in the warm sector, falling pressure behind the cold front - **D)** Rising pressure ahead of the warm front, rising pressure in the warm sector, falling pressure behind the cold front #### Answer A) #### Explanation The classic pressure trace of a passing polar front low follows three phases: pressure falls as the warm front approaches (the low draws nearer), pressure holds relatively steady in the warm sector between the two fronts, and pressure rises sharply after the cold front passes as cold, dense air replaces the warm sector. - **Option B** wrongly has pressure rising ahead of the warm front. - **Option C** has pressure falling behind the cold front, contradicting the arrival of dense cold air. - **Option D** reverses the entire pattern. #### Source - [?] Source non identifiée ### Q136: As a polar front low passes through Central Europe, what wind direction changes are typically observed? ^t50q136 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q136) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q136) - **A)** Backing at both the warm front and the cold front - **B)** Veering at the warm front, backing at the cold front - **C)** Backing at the warm front, veering at the cold front - **D)** Veering at both the warm front and the cold front #### Answer D) #### Explanation In the Northern Hemisphere, as a typical polar front low passes, wind veers (shifts clockwise) at both frontal passages. At the warm front, wind veers from southeast to south or southwest. At the cold front, it veers again from southwest to west or northwest. This consistent clockwise shift indicates the low is passing to the north of the observer, which is the normal track for lows crossing Central Europe. Backing (A, B, C) would indicate the low passing to the south — an uncommon trajectory. #### Source - [?] Source non identifiée ### Q137: What pressure pattern may develop from cold-air intrusion in the upper troposphere? ^t50q137 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q137) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q137) - **A)** Development of a low in the upper troposphere - **B)** Development of a high in the upper troposphere - **C)** Oscillating pressure - **D)** Development of a large surface low #### Answer A) #### Explanation When cold air intrudes into the upper troposphere, it reduces the thickness of the atmospheric column (cold air is denser and occupies less vertical space), causing the heights of upper pressure surfaces to drop. This creates an upper-level low or trough. These cold-pool lows aloft are potent triggers for convective instability and often initiate cyclogenesis at the surface. - An upper high **(B)** would form from warm-air advection, not cold intrusion. - Oscillating pressure **(C)** and a large surface low **(D)** are not the direct or primary consequence of upper-level cold intrusion. #### Source - [?] Source non identifiée ### Q138: Cold air flowing into the upper troposphere may lead to ^t50q138 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q138) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q138) - **A)** Stabilisation and settled weather. - **B)** Frontal weather systems. - **C)** Showers and thunderstorms. - **D)** Calm weather and cloud dissipation. #### Answer C) #### Explanation Cold air advecting into the upper troposphere steepens the lapse rate (cold air aloft over relatively warmer air below), producing conditional or even absolute instability. This destabilisation triggers convection, generating showers and thunderstorms — especially when combined with surface moisture and daytime heating. - Stabilisation and settled weather **(A)** and calm conditions **(D)** are the opposite of what cold upper-air intrusion produces. - Frontal weather **(B)** requires surface air-mass boundaries, which are not a direct result of upper-tropospheric cooling. #### Source - [?] Source non identifiée ### Q139: How does an influx of cold air affect the shape and vertical spacing of pressure layers? ^t50q139 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q139) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q139) - **A)** Increased vertical spacing, raising of heights (high pressure) - **B)** Decreased vertical spacing, raising of heights (high pressure) - **C)** Increased vertical spacing, lowering of heights (low pressure) - **D)** Decreased vertical spacing, lowering of heights (low pressure) #### Answer D) #### Explanation Cold air is denser than warm air, so a cold air column has less vertical distance (decreased spacing) between any two pressure surfaces. Because the column is compressed, the upper pressure surfaces lie at lower geometric heights, which is identified as low pressure aloft on hypsometric charts. This is why upper-level lows are always associated with cold-core air masses. Warm air produces the opposite: increased spacing and raised heights (high pressure aloft), as described in options A and C. #### Source - [VV Q53 p.118](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=118) (score: 0.21) - [QuizVDS Q88](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q88): Answer C - PDF Answer: D ### Q140: During summer, what weather is typical of high pressure areas? ^t50q140 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q140) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q140) - **A)** Squall lines and thunderstorm activity - **B)** Settled weather with cloud dissipation, a few high Cu - **C)** Changeable weather with frontal passages - **D)** Light winds with widespread high fog #### Answer B) #### Explanation In summer, anticyclones bring subsiding air that warms adiabatically, suppressing deep convection and producing clear to partly cloudy skies with perhaps a few fair-weather cumulus (Cu humilis) from daytime thermal heating. The overall character is settled, warm, and dry. - Squall lines and thunderstorms **(A)** require convective instability not present in a well-established high. - Frontal passages **(C)** are features of low-pressure troughs. - Widespread high fog **(D)** is a winter high-pressure phenomenon caused by temperature inversions trapping cold moist air. #### Source - [?] Source non identifiée ### Q141: On the windward side of a mountain range during Foehn conditions, what weather should be expected? ^t50q141 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q141) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q141) - **A)** Scattered cumulus clouds accompanied by showers and thunderstorms - **B)** Light wind with formation of high stratus (high fog) - **C)** Layered clouds, mountains obscured, poor visibility, moderate to heavy rain - **D)** Cloud dissipation with unusual warming, strong gusty winds #### Answer C) #### Explanation On the windward (Stau) side during Foehn, moist air is forced to rise over the mountain barrier, cooling adiabatically and producing dense layered clouds (stratus, nimbostratus), obscured mountain peaks, poor visibility, and moderate to heavy orographic precipitation. - **Option D** describes the lee-side Foehn effect — warm, dry, gusty descending wind — which is the opposite side of the mountains. - **Option A** describes convective (unstable) weather, not the organised forced ascent of a Foehn pattern. - **Option B** describes stagnant anticyclonic conditions, not active orographic lifting. #### Source - [?] Source non identifiée ### Q142: Which chart depicts areas of precipitation? ^t50q142 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q142) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q142) - **A)** Wind chart - **B)** Radar picture - **C)** GAFOR - **D)** Satellite picture #### Answer B) #### Explanation Weather radar detects precipitation directly by measuring the intensity of microwave energy backscattered from raindrops, snowflakes, and hail. Radar imagery shows the precise location, extent, and intensity of precipitation areas in near-real-time. - A satellite picture **(D)** shows cloud cover but cannot directly distinguish precipitating from non-precipitating clouds. - A wind chart **(A)** displays wind patterns only. - A GAFOR **(C)** is a coded route forecast for general aviation that categorises flying conditions but does not depict precipitation areas graphically. #### Source - [?] Source non identifiée ### Q143: An inversion is an atmospheric layer where ^t50q143 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q143) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q143) - **A)** Pressure increases with increasing height. - **B)** Temperature remains constant with increasing height. - **C)** Temperature decreases with increasing height. - **D)** Temperature increases with increasing height. #### Answer D) #### Explanation An inversion is a layer of the atmosphere where temperature increases with altitude, which is the reverse ("inversion") of the normal tropospheric lapse rate. Inversions are extremely stable and act as lids that suppress convection, trap pollution, and limit thermal development for glider pilots. - **Option B** describes an isothermal layer (constant temperature). - **Option C** describes the normal lapse rate. - **Option A** is incorrect because atmospheric pressure always decreases with height, regardless of the temperature profile. #### Source - [VV Q122 p.132](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=132) (score: 0.43) - [QuizVDS Q121](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q121): Answer C - PDF Answer: D ### Q144: Which condition may prevent radiation fog from forming? ^t50q144 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q144) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q144) - **A)** A clear, cloudless night - **B)** Low temperature-dew point spread - **C)** Overcast cloud cover - **D)** Calm wind conditions #### Answer C) #### Explanation Radiation fog requires the ground to radiate longwave heat to space, cooling the surface air to the dew point. An overcast cloud layer acts as a blanket, absorbing and re-emitting radiation back toward the ground, preventing the surface from cooling sufficiently. Therefore, overcast cloud cover prevents radiation fog formation. A clear night **(A)**, low spread **(B)**, and calm wind **(D)** all favour fog formation — they are prerequisites, not preventative conditions. #### Source - [S1C Q12 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.22) - [QuizVDS Q63](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q63): Answer D - PDF Answer: B ### Q145: On the chart, the symbol labelled (3) represents a / an ^t50q145 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q145) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q145) ![](figures/t50_q145.png) - **A)** Warm front. - **B)** Cold front. - **C)** Occlusion. - **D)** Front aloft. #### Answer C) #### Explanation An occluded front is depicted on synoptic charts by a line combining both the cold front triangles and the warm front semicircles on the same side, representing the merger of the two fronts when the faster-moving cold front overtakes the warm front. Symbol (3) in figure shows this combined symbology, identifying it as an occlusion. - A warm front **(A)** uses only semicircles. - A cold front **(B)** uses only triangles. - A front aloft **(D)** has a distinct marking indicating the frontal surface does not reach the ground. #### Source - [?] Source non identifiée ### Q146: A boundary between a cold polar air mass and a warm subtropical air mass that shows no horizontal movement is known as a ^t50q146 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q146) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q146) - **A)** Warm front. - **B)** Occluded front. - **C)** Stationary front. - **D)** Cold front. #### Answer C) #### Explanation A stationary front is a boundary between two contrasting air masses — here polar and subtropical — that is not moving significantly in either direction. Neither the cold air nor the warm air is advancing. - A cold front **(D)** is specifically an advancing cold air mass pushing warm air aside. - A warm front **(A)** is advancing warm air overriding cold air. - An occluded front **(B)** results from a cold front overtaking a warm front within a mature cyclone — it involves merging fronts, not stationary boundaries. #### Source - [VV Q95 p.127](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=127) (score: 0.24) - [QuizVDS Q79](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q79): Answer C - PDF Answer: B ### Q147: Which situation may lead to severe wind shear? ^t50q147 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q147) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q147) - **A)** Cross-country flying beneath Cu clouds at roughly 4 octas coverage - **B)** A shower visible in the vicinity of the airfield - **C)** Final approach 30 minutes after a heavy shower has cleared the airfield - **D)** Flying ahead of a warm front with Ci clouds visible #### Answer B) #### Explanation An active shower near an airfield indicates ongoing convective downdrafts and outflow boundaries that create severe, rapidly changing low-level wind shear — a critical hazard during takeoff and landing. The gust front from a nearby shower can change wind direction and speed dramatically within seconds. - Cross-country flying below moderate Cu **(A)** involves normal soaring conditions. - Thirty minutes after a shower **(C)**, conditions have typically stabilised. - Cirrus ahead of a warm front **(D)** is an upper-level indicator without immediate low-level shear implications. #### Source - [?] Source non identifiée ### Q148: Which kind of visibility reduction is largely unaffected by temperature changes? ^t50q148 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q148) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q148) - **A)** Mist (BR) - **B)** Patches of fog (BCFG) - **C)** Haze (HZ) - **D)** Radiation fog (FG) #### Answer C) #### Explanation Haze (HZ) is caused by dry particulates — dust, smoke, industrial pollution, and fine sand — suspended in the atmosphere. Because these particles are not moisture-dependent, haze persists regardless of temperature changes. Mist **(A)**, fog patches **(B)**, and radiation fog **(D)** are all formed by water droplet suspension and are highly sensitive to temperature: warming evaporates the droplets and improves visibility, while cooling promotes further condensation and worsens it. #### Source - [?] Source non identifiée ### Q149: In a METAR, how are moderate showers of rain encoded? ^t50q149 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q149) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q149) - **A)** TS. - **B)** .+RA. - **C)** SHRA. - **D)** .+TSRA #### Answer C) #### Explanation In METAR format, the descriptor "SH" (shower) is combined with the precipitation type "RA" (rain) to form "SHRA," which denotes moderate showers of rain. No intensity prefix means moderate. "+RA" **(B)** indicates heavy continuous rain, not a shower. "TS" **(A)** denotes a thunderstorm without specifying precipitation type. "+TSRA" **(D)** indicates a heavy thunderstorm with rain — a more severe phenomenon than a simple rain shower. #### Key Terms METAR = Aerodrome routine weather report #### Source - [?] Source non identifiée ### Q150: For which areas are SIGMET warnings issued? ^t50q150 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q150) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q150) - A) Airports. - B) FIRs / UIRs. - C) Specific routings. - D) Countries. #### Answer B) #### Explanation SIGMET (Significant Meteorological Information) warnings are issued for Flight Information Regions (FIRs) and Upper Information Regions (UIRs), which are standardised ICAO airspace blocks managed by specific ATC authorities. They warn of hazardous weather phenomena (severe turbulence, icing, volcanic ash, thunderstorms) within these defined airspace volumes. - SIGMETs are not issued for individual airports **(A)** — those use AIRMETs or aerodrome warnings. - They are not route-specific **(C)** or country-specific **(D)**, as a single country may contain multiple FIRs. #### Key Terms - **ATC** = Air Traffic Control - **ICAO** = International Civil Aviation Organization - **SIGMET** = Significant Meteorological Information #### Source - [?] Source non identifiée ### Q151: Updrafts along a mountain slope can be strengthened by ^t50q151 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q151) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q151) - A) Warming of upper atmospheric layers - B) Thermal radiation from the windward side at night - C) Solar heating on the lee side - D) Solar heating on the windward side #### Answer D) #### Explanation Solar heating on the windward slope warms the surface air, making it less dense and creating anabatic (upslope) flow that combines with the mechanical orographic lift from the oncoming wind, significantly strengthening the updraft. This is why south- and west-facing slopes in the Northern Hemisphere often produce the strongest lift during sunny afternoons. - **Option A** (warming of upper layers) would increase stability and suppress convection. - **Option B** (nighttime radiation from the windward side) produces cooling and katabatic (downslope) flow, the opposite of updrafts. - **Option C** (solar heating on the lee side) does not contribute to windward-side updrafts. #### Source - [?] Source non identifiée ### Q152: The prefix used for clouds in the high layers is ^t50q152 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q152) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q152) - **A)** Alto-. - **B)** Nimbo-. - **C)** Strato-. - **D)** Cirro-. #### Answer D) #### Explanation The prefix "Cirro-" identifies clouds in the high cloud family, typically found above approximately 6000 m (FL200) in mid-latitudes, and includes cirrus, cirrocumulus, and cirrostratus — all composed primarily of ice crystals. - **Option A** ("Alto-") designates mid-level clouds between roughly 2000 and 6000 m, such as altostratus and altocumulus. - **Option B** ("Nimbo-") indicates rain-producing clouds regardless of altitude, such as nimbostratus. - **Option C** ("Strato-") refers to layered cloud forms at low to mid levels. #### Key Terms FL = Flight Level #### Source - [?] Source non identifiée ### Q153: What factor may limit the vertical extent of cumulus clouds at the top? ^t50q153 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q153) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q153) - A) The presence of an inversion layer - B) The absolute humidity - C) Relative humidity - D) The spread #### Answer A) #### Explanation An inversion layer creates a zone where temperature increases with altitude, forming a highly stable lid that stops rising thermals from penetrating further upward. Cumulus clouds reaching this barrier flatten out and spread horizontally rather than continuing to develop vertically, which is why fair-weather cumulus often have a uniform top height. - **Option D** (the spread, i.e., temperature minus dew point) determines cloud base height, not cloud top. - **Options B** (absolute humidity) and C (relative humidity) influence whether clouds form at all but do not cap their vertical extent the way an inversion does. #### Source - [?] Source non identifiée ### Q154: Which factors point toward a tendency for fog formation? ^t50q154 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q154) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q154) - **A)** Strong winds with falling temperature - **B)** Low pressure with rising temperature - **C)** Small spread with falling temperature - **D)** Small spread with rising temperature #### Answer C) #### Explanation A small spread (temperature close to dew point) means the air is already near saturation, and falling temperature will close the remaining gap, causing condensation at or near the surface — fog. These are the classic pre-fog conditions monitored by pilots and forecasters. - **Option A** (strong winds) promotes turbulent mixing that prevents the surface layer from reaching saturation. - **Option B** (low pressure with rising temperature) widens the spread and favours lifting rather than surface fog. - **Option D** (rising temperature) increases the spread, moving conditions away from saturation. #### Source - [?] Source non identifiée ### Q155: What process gives rise to orographic fog (hill fog)? ^t50q155 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q155) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q155) - **A)** Extended radiation on cloud-free nights - **B)** Evaporation from warm, moist ground into very cold air - **C)** Cold, moist air mixing with warm, moist air - **D)** Warm, moist air forced over a hill or mountain range #### Answer D) #### Explanation Orographic fog (hill fog) forms when warm, moist air is forced to ascend over elevated terrain, cooling adiabatically until it reaches the dew point and condenses. The resulting cloud envelops the hill or mountain and appears as fog to anyone on the slope or summit. - **Option A** describes the formation mechanism of radiation fog, which occurs on calm, clear nights over flat terrain. - **Option B** describes steam fog (or evaporation fog), which forms when cold air passes over much warmer water or moist surfaces. - **Option C** describes frontal or mixing fog, a different process entirely. #### Source - [?] Source non identifiée ### Q156: What is needed for precipitation to form inside clouds? ^t50q156 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q156) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q156) - **A)** High humidity and elevated temperatures - **B)** An inversion layer - **C)** Moderate to strong updrafts - **D)** Calm winds and intense solar insolation #### Answer C) #### Explanation Precipitation particles need time to grow large enough to fall against the updraft, either through collision-coalescence (warm rain process) or the Bergeron ice-crystal process. Moderate to strong updrafts keep water droplets and ice crystals suspended in the cloud long enough for this growth to occur. - **Option A** (high humidity and elevated temperatures) favours cloud formation but does not ensure particles grow to precipitation size. - **Option B** (an inversion layer) suppresses cloud development and works against precipitation. - **Option D** (calm winds and sunshine) describes surface conditions that do not directly produce in-cloud precipitation. #### Source - [?] Source non identifiée ### Q157: In areas where isobars are widely spaced, what wind conditions should be expected? ^t50q157 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q157) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q157) - **A)** Strong prevailing easterly winds with rapid backing - **B)** Strong prevailing westerly winds with rapid veering - **C)** Local wind systems developing with strong prevailing westerly winds - **D)** Variable winds with the development of local wind systems #### Answer D) #### Explanation Widely spaced isobars indicate a weak horizontal pressure gradient, which produces only light synoptic-scale winds. In the absence of a dominant pressure-driven flow, local thermally driven wind systems — such as valley-mountain breezes, sea-land breezes, and slope winds — become the primary circulation features, with wind direction varying throughout the day. - **Options A, B, and C** all describe strong prevailing winds, which require closely spaced isobars (a steep pressure gradient) and are therefore inconsistent with the wide spacing described. #### Source - [?] Source non identifiée ### Q158: Under what circumstances does back side weather (Rückseitenwetter) occur? ^t50q158 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q158) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q158) - **A)** After passage of a warm front - **B)** During Foehn on the lee side - **C)** Before passage of an occlusion - **D)** After passage of a cold front #### Answer D) #### Explanation "Back-side weather" (Rückseitenwetter) describes the conditions in the cold, unstable polar air mass that follows behind a cold front on the western or northwestern side of a low-pressure system. It is characterized by good visibility, convective cumulus clouds, and scattered showers or snow showers. - **Option A** (after a warm front) leads into the warm sector, not the cold back side. - **Option B** (Foehn on the lee side) is a thermodynamic mountain phenomenon unrelated to frontal weather. - **Option C** (before an occlusion) describes pre-frontal conditions, not back-side weather. #### Source - [?] Source non identifiée ### Q159: How is a wind reported as 225/15 described? ^t50q159 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q159) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q159) - **A)** South-west wind at 15 km/h - **B)** North-east wind at 15 km/h - **C)** North-east wind at 15 kt - **D)** South-west wind at 15 kt #### Answer D) #### Explanation In aviation weather reporting, wind is always given as the direction FROM which it blows (in degrees true) followed by speed in knots. A report of 225/15 means wind from 225 degrees (southwest) at 15 knots. - **Options B and C** incorrectly interpret 225 degrees as northeast, perhaps confusing the direction the wind blows from with the direction it blows toward. - **Option A** gives the correct direction but uses km/h instead of the standard aviation unit of knots. #### Source - [VV Q54 p.118](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=118) (score: 0.36) - [QuizVDS Q126](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q126): Answer B - PDF Answer: D ### Q160: In the Bavarian area near the Alps, what weather typically accompanies Foehn conditions? ^t50q160 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q160) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q160) - **A)** Nimbostratus on the northern Alps, rotor clouds on the windward side, warm dry wind - **B)** High pressure over Biscay and a low over Eastern Europe - **C)** Cold, humid downslope wind on the lee side, flat pressure pattern - **D)** Nimbostratus on the southern Alps, rotor clouds on the lee side, warm dry wind #### Answer D) #### Explanation During Foehn in the Bavarian pre-alpine region, the prevailing southerly flow forces moist air up the southern (Italian) side of the Alps, producing nimbostratus and heavy orographic precipitation there. As the air descends on the northern (Bavarian) lee side, it warms adiabatically and dries out, creating the characteristic warm, dry, gusty Foehn wind. Rotor clouds and lenticular clouds form on the lee side due to wave activity. - **Option A** incorrectly places nimbostratus on the northern side and rotors on the windward side. - **Option B** describes a synoptic pattern, not the weather itself. - **Option C** contradicts the definition of Foehn, which produces warm, dry — not cold, humid — descending air. #### Source - [?] Source non identifiée ### Q161: Clouds are fundamentally classified into which two basic types? ^t50q161 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q161) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q161) - **A)** Stratiform and ice clouds - **B)** Layered and lifted clouds - **C)** Thunderstorm and shower clouds - **D)** Cumulus and stratiform clouds #### Answer D) #### Explanation The fundamental cloud classification divides all clouds into two basic forms based on their physical formation process: cumuliform (convective, vertically developed clouds formed by localized updrafts) and stratiform (layered, horizontally extended clouds formed by widespread, gentle lifting or cooling). All other cloud types and subtypes derive from combinations of these two basic forms. - **Option A** incorrectly pairs stratiform with "ice clouds," which is a composition category, not a form. - **Option B** uses non-standard terminology. - **Option C** names specific weather phenomena rather than fundamental cloud forms. #### Source - [?] Source non identifiée ### Q162: During Foehn conditions, what weather phenomenon marked as "2" should be expected on the lee side?. ^t50q162 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q162) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q162) ![](figures/t50_q162.png) - **A)** Altocumulus Castellanus - **B)** Cumulonimbus - **C)** Altocumulus lenticularis - **D)** Cirrostratus #### Answer C) #### Explanation On the lee side during Foehn conditions, the descending air creates standing wave patterns downwind of the mountain ridge. These waves produce Altocumulus lenticularis — smooth, lens-shaped or almond-shaped clouds that remain stationary relative to the terrain despite strong winds passing through them. They are a hallmark of mountain wave activity. - **Options B and D** (cumulonimbus) are associated with deep convective instability, not the stable laminar wave flow characteristic of Foehn. - **Option A** (Altocumulus castellanus) indicates mid-level convective instability with turret-like protrusions, which is a different meteorological situation. #### Source - [?] Source non identifiée ### Q163: When very small water droplets and ice crystals strike the leading surfaces of an aircraft, which type of ice forms? ^t50q163 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q163) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q163) - **A)** Hoar frost - **B)** Clear ice - **C)** Rime ice - **D)** Mixed ice #### Answer C) #### Explanation Rime ice forms when very small supercooled water droplets freeze instantly upon contact with the aircraft's leading edges, trapping air between the frozen particles and creating a rough, white, opaque deposit. Because the droplets are so small, they freeze before they can spread, resulting in the characteristic granular texture. - **Option B** (clear ice) forms from larger supercooled droplets that flow along the surface before freezing, producing a smooth, transparent, dense layer. - **Option D** (mixed ice) is a combination of rime and clear ice. - **Option A** (hoar frost) forms by direct deposition of water vapour onto cold surfaces, not by droplet impact. #### Source - [?] Source non identifiée ### Q164: Which chart contains information about pressure patterns and frontal positions? ^t50q164 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q164) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q164) - **A)** Significant Weather Chart (SWC) - **B)** Surface weather chart. - **C)** Hypsometric chart - **D)** Wind chart. #### Answer B) #### Explanation The surface weather chart (synoptic analysis chart) is the primary meteorological product displaying isobars (lines of equal pressure at MSL), the locations of highs and lows, and the positions and types of fronts (warm, cold, occluded, stationary). - **Option A** (Significant Weather Chart) focuses on aviation hazards such as turbulence, icing, and significant cloud coverage, but does not show the full surface pressure pattern. - **Option C** (hypsometric chart) depicts the heights of constant-pressure surfaces in the upper atmosphere. - **Option D** (wind chart) shows wind speed and direction at specific levels without pressure or frontal information. #### Key Terms MSL = Mean Sea Level #### Source - [?] Source non identifiée ### Q165: What is the typical cloud sequence observed during the approach and passage of a warm front? ^t50q165 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q165) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q165) - A) Squall line with rain showers and thunderstorms (Cb), gusty wind followed by cumulus with isolated showers - B) In coastal areas, daytime wind from the coast with cumulus forming, clouds dissipating in the evening - C) Cirrus, thickening altostratus and altocumulus, lowering cloud base with rain, nimbostratus - D) Wind calming, cloud dissipation and warming in summer; extensive high fog layers forming in winter #### Answer C) #### Explanation The approach of a warm front produces a characteristic descending cloud sequence as the warm air gradually overrides the retreating cold air mass. First, thin cirrus appears at high altitude, followed by cirrostratus, then progressively thickening altostratus and altocumulus at mid-levels, and finally nimbostratus with a low cloud base and prolonged steady rain. - **Option A** describes cold front or squall line weather. - **Option B** describes a coastal sea-breeze cycle unrelated to frontal meteorology. - **Option D** describes anticyclonic subsidence or continental high-pressure conditions. #### Source - [?] Source non identifiée ### Q166: What phenomenon results from cold-air downdrafts carrying precipitation from a fully developed thunderstorm cloud? ^t50q166 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q166) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q166) - **A)** Anvil-head top of the Cb cloud - **B)** Freezing rain - **C)** Electrical discharge - **D)** Gust front #### Answer D) #### Explanation In a mature thunderstorm, precipitation drags cold air downward in powerful downdrafts. When this cold, dense air reaches the surface, it spreads outward rapidly as a density current, creating a gust front — a sharp boundary marked by sudden wind shifts, temperature drops, and gusty conditions that can extend several kilometres ahead of the storm. - **Option A** (anvil-head top) is a structural feature shaped by upper-level winds, not caused by downdrafts reaching the surface. - **Option C** (electrical discharge) results from charge separation within the cloud. - **Option B** (freezing rain) requires a specific temperature inversion profile, not downdraft spreading. #### Source - [?] Source non identifiée ### Q167: Which item is NOT included on Low-Level Significant Weather Charts (LLSWC)? ^t50q167 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q167) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q167) - **A)** Frontal lines and frontal displacement - **B)** Turbulence area information - **C)** Icing condition information - **D)** Radar echoes of precipitation #### Answer D) #### Explanation Low-Level Significant Weather Charts are forecast products that depict meteorological hazards below a specified altitude, including frontal systems and their movement (option A), turbulence areas (option B), and icing conditions (option C). However, they do not contain radar echoes of precipitation (option D) because radar imagery is a real-time observational product, whereas LLSWC are prognostic charts prepared in advance. Precipitation areas may be indicated symbolically on LLSWC, but actual radar returns are found only on separate radar displays. #### Source - [?] Source non identifiée ### Q168: Which cloud type produces prolonged, steady rain? ^t50q168 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q168) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q168) - **A)** Cirrostratus - **B)** Altocumulus - **C)** Nimbostratus - **D)** Cumulonimbus #### Answer C) #### Explanation Nimbostratus (Ns) is a thick, dark grey, amorphous layer cloud that produces continuous, steady precipitation (rain or snow) over wide areas, typically associated with warm fronts or occlusions. Its great vertical and horizontal extent ensures prolonged precipitation reaching the ground. - **Option A** (cirrostratus) is a thin, high-level ice cloud that does not produce surface precipitation. - **Option B** (altocumulus) is a mid-level cloud that occasionally produces virga but not sustained surface rain. - **Option D** (cumulonimbus) produces intense but short-lived showers and thunderstorms rather than prolonged steady rain. #### Source - [VV Q70 p.121](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=121) (score: 0.21) - [QuizVDS Q68](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q68): Answer C - PDF Answer: A ### Q169: Based on cloud type, how is precipitation classified? ^t50q169 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q169) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q169) - **A)** Light and heavy precipitation. - **B)** Prolonged rain and continuous rain. - **C)** Showers of snow and rain. - **D)** Rain and showers of rain. #### Answer D) #### Explanation Meteorological classification of precipitation by cloud type distinguishes two fundamental categories: rain (steady, continuous precipitation from stratiform clouds like nimbostratus) and showers of rain (intermittent, convective precipitation from cumuliform clouds like cumulonimbus or cumulus congestus). This distinction reflects the physical formation process — widespread lifting versus localized convection. - **Option A** classifies by intensity rather than cloud type. - **Option B** uses redundant terminology that does not distinguish cloud origins. - **Option C** classifies by precipitation phase (snow versus rain), not by cloud type. #### Source - [?] Source non identifiée ### Q170: Which conditions favour thunderstorm development? ^t50q170 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q170) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q170) - **A)** Clear night over land with cold air and fog patches - **B)** Warm, dry air under a strong inversion layer - **C)** Calm winds with cold air, overcast St or As cloud cover - **D)** Warm, humid air with a conditionally unstable environmental lapse rate #### Answer D) #### Explanation Thunderstorm development requires three essential ingredients: moisture (warm, humid air provides the latent heat fuel), instability (a conditionally unstable lapse rate allows saturated air parcels to accelerate upward), and a lifting mechanism (fronts, orographic forcing, or surface heating). - **Option D** combines the first two ingredients explicitly. - **Option A** describes calm, stable nighttime conditions favouring radiation fog, not convection. - **Option B** features a strong inversion that would cap any vertical development. - **Option C** describes a stable, overcast situation with stratus or altostratus, which suppresses thunderstorm formation. #### Source - [VV Q138 p.136](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=136) (score: 0.21) - PDF Answer: C ### Q171: When isobars on a surface weather chart are widely spaced, what does this indicate about the prevailing wind? ^t50q171 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q171) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q171) - **A)** Strong pressure gradients producing strong prevailing wind - **B)** Weak pressure gradients producing light prevailing wind - **C)** Strong pressure gradients producing light prevailing wind - **D)** Weak pressure gradients producing strong prevailing wind #### Answer B) #### Explanation The spacing of isobars on a surface weather chart is inversely proportional to the pressure gradient: widely spaced isobars mean a small pressure difference over a large distance (weak gradient), which produces only light wind. Wind speed is directly driven by the pressure gradient force, so a weak gradient means weak wind. - **Option A** contradicts itself by associating wide spacing with strong gradients. - **Option C** pairs a strong gradient with light wind, which is meteorologically incorrect. - **Option D** reverses the gradient-wind relationship. #### Source - [?] Source non identifiée ### Q172: An air mass arriving in Central Europe from the Russian continent during winter is described as ^t50q172 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q172) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q172) - **A)** Continental tropical air - **B)** Maritime polar air - **C)** Continental polar air - **D)** Maritime tropical air #### Answer C) #### Explanation Air masses are classified by their source region's surface characteristics. Air originating over the vast, snow-covered Russian (Siberian) continent during winter acquires cold temperatures and very low moisture content, making it Continental Polar (cP). This air mass brings bitterly cold, dry conditions to Central Europe when it advects westward. - **Option B** (maritime polar) originates over polar oceans and carries significant moisture. - **Option A** (continental tropical) and option D (maritime tropical) originate in warm regions and are far too warm and/or moist to describe Siberian winter air. #### Source - [S1C Q14 p.22](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Communes.pdf#page=22) (score: 0.32) - [QuizVDS Q70](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q70): Answer B - PDF Answer: A ### Q173: What clouds and weather are typically observed during the passage of a cold front? ^t50q173 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q173) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q173) - **A)** Strongly developed Cb clouds with rain showers and thunderstorms, gusty wind followed by cumulus with isolated showers - **B)** Wind calming, cloud dissipation and warming in summer; extensive high fog in winter - **C)** Cirrus, thickening altostratus and altocumulus, lowering cloud base with rain, nimbostratus - **D)** In coastal areas, daytime onshore wind with cumulus forming, clouds dissipating in evening #### Answer A) #### Explanation Cold front passage is marked by a narrow band of intense weather as the advancing cold air undercuts the warm air, forcing it rapidly aloft. This produces strongly developed cumulonimbus (Cb) clouds, heavy rain showers, thunderstorms, and gusty winds along the frontal line, followed by cumulus with isolated showers in the cold, unstable air behind the front. - **Option C** describes the gradual cloud sequence of an approaching warm front. - **Option B** describes anticyclonic or high-pressure settling conditions. - **Option D** describes a coastal sea-breeze pattern unrelated to frontal weather. #### Source - [?] Source non identifiée ### Q174: When an aircraft is struck by lightning, what is the most immediate danger? ^t50q174 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q174) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q174) - **A)** Disrupted radio communication and static noise - **B)** Rapid cabin depressurisation and smoke in the cabin - **C)** Surface overheating and damage to exposed aircraft parts - **D)** Explosion of electrical equipment in the cockpit #### Answer C) #### Explanation The most immediate physical danger from a lightning strike is surface overheating at the attachment and exit points, along with damage to exposed components such as antennas, pitot tubes, wingtips, and control surface edges. The extreme heat at the strike points can burn through thin skins, pit metal surfaces, and damage composite materials. - **Option A** (disrupted radio communication) is a secondary effect that does not pose an immediate structural threat. - **Option B** (cabin depressurisation) applies primarily to pressurised aircraft and is not the most common immediate consequence. - **Option D** (explosion of cockpit equipment) is extremely unlikely in certified aircraft with proper lightning protection. #### Source - [?] Source non identifiée ### Q175: What is meant by mountain wind? ^t50q175 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q175) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q175) - **A)** A wind blowing uphill from the valley during daytime. - **B)** A wind blowing down the mountain slope at night. - **C)** A wind blowing uphill from the valley at night. - **D)** A wind blowing down the mountain slope during daytime. #### Answer B) #### Explanation Mountain wind (Bergwind) is a katabatic flow that occurs at night when mountain slopes cool by radiation faster than the free atmosphere at the same altitude. The cooled, denser air drains downslope under gravity toward the valley floor. This is part of the diurnal mountain-valley wind cycle. - **Option A** describes valley wind (Talwind), which is the daytime anabatic upslope flow caused by solar heating. - **Option C** reverses the nighttime flow direction. - **Option D** reverses the daytime flow direction. #### Source - [?] Source non identifiée ### Q176: What is the average value of the saturated adiabatic lapse rate? ^t50q176 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q176) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q176) - **A)** 0° C / 100 m. - **B)** 2° C / 1000 ft. - **C)** 1,0° C / 100 m. - **D)** 0,6° C / 100 m. #### Answer D) #### Explanation The saturated (moist) adiabatic lapse rate averages approximately 0.6 degrees C per 100 m. It is lower than the dry adiabatic lapse rate (1.0 degrees C per 100 m) because latent heat released during condensation partially offsets the cooling of the ascending air parcel. - **Option A** (0 degrees C per 100 m) would mean no temperature change with altitude, which is physically unrealistic for a rising air parcel. - **Option B** (2 degrees C per 1000 ft, approximately 0.66 degrees C per 100 m) is a rough approximation but not the standard textbook value. - **Option C** (1.0 degrees C per 100 m) is the dry adiabatic lapse rate, not the saturated rate. #### Source - [S1S Q1 p.40](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_1_Specifiques.pdf#page=40) (score: 0.23) - [QuizVDS Q51](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q51): Answer D ### Q177: Throughout the year, extensive high pressure areas are found ^t50q177 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q177) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q177) - **A)** In tropical regions near the equator. - **B)** Over oceanic areas at approximately 30°N/S latitude. - **C)** In mid-latitudes along the polar front. - **D)** In areas with extensive lifting processes. #### Answer B) #### Explanation The subtropical high-pressure belt at approximately 30 degrees N and S latitude is a semi-permanent feature of the global atmospheric circulation, created by the descending branch of the Hadley cell. Warm air rising near the equator flows poleward aloft, cools, and subsides in the subtropics, forming persistent anticyclones over the oceans (e.g., the Azores High, the Pacific High). - **Option A** (equatorial regions) is dominated by the low-pressure Intertropical Convergence Zone (ITCZ). - **Option C** (mid-latitudes along the polar front) is a zone of cyclonic activity and low pressure. - **Option D** (areas with extensive lifting) produce low pressure by definition, not high pressure. #### Source - [?] Source non identifiée ### Q178: During flight, weather and operational information about the destination aerodrome can be obtained via ^t50q178 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q178) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q178) - **A)** SIGMET - **B)** ATIS. - **C)** PIREP - **D)** VOLMET. #### Answer B) #### Explanation ATIS (Automatic Terminal Information Service) is a continuous broadcast available on a dedicated frequency at equipped aerodromes, providing current weather observations, active runway, transition level, approach procedures, and relevant NOTAMs specific to that aerodrome. Pilots tune in to the ATIS frequency during flight to obtain up-to-date destination information. - **Option A** (SIGMET) covers significant weather hazards across an entire FIR, not aerodrome-specific data. - **Option C** (PIREP) contains pilot-reported weather conditions en route. - **Option D** (VOLMET) broadcasts weather for multiple aerodromes but is less comprehensive than ATIS for a specific destination. #### Key Terms - **D** — Drag - **ATIS** = Automatic Terminal Information Service - **FIR** = Flight Information Region - **SIGMET** = Significant Meteorological Information - **VOLMET** = Weather broadcasts for aircraft in flight #### Source - [?] Source non identifiée ### Q179: Identify the cloud type shown in the picture.. ^t50q179 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q179) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q179) ![](figures/t50_q179.png) - A) Cumulus - B) Cirrus - C) Stratus - D) Altus #### Answer A) #### Explanation The cloud in figure is cumulus, identifiable by its characteristic flat base (marking the condensation level) and vertically developed, cauliflower-like top with sharp white outlines against the blue sky. Cumulus clouds form through thermal convection and are the clouds most associated with soaring flight. - **Option B** (cirrus) would appear as thin, wispy ice-crystal filaments at very high altitude. - **Option C** (stratus) would present as a uniform, featureless grey layer. - **Option D** ("altus") is not a recognized cloud genus in the international cloud classification system. #### Source - [VV Q146 p.137](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=137) (score: 0.20) - PDF Answer: C ### Q180: What determines the character of an air mass? ^t50q180 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q180) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q180) - **A)** Wind speed and tropopause height - **B)** Region of origin and trajectory during movement - **C)** Environmental lapse rate at the source - **D)** Temperatures at both origin and present location #### Answer B) #### Explanation An air mass acquires its temperature and moisture properties from the surface conditions of its source region (e.g., polar continent, tropical ocean) and then modifies as it travels over different surfaces along its trajectory. Both the origin (which sets the initial character) and the path (which modifies it) are essential for classifying and forecasting air mass behaviour. - **Option A** (wind speed and tropopause height) are dynamic properties, not defining characteristics. - **Option C** (environmental lapse rate at source) is a consequence of the air mass properties, not their cause. - **Option D** (temperatures at origin and present location) captures only temperature while ignoring the critical moisture dimension. #### Source - [?] Source non identifiée ### Q181: What cloud type is commonly observed across extensive high-pressure areas in summer? ^t50q181 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q181) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q181) - **A)** Squall lines and thunderstorms - **B)** Overcast nimbostratus - **C)** Scattered cumulus clouds - **D)** Overcast low stratus #### Answer C) #### Explanation In summer anticyclones, surface heating generates thermal convection that produces scattered fair-weather Cumulus clouds (Cu humilis or Cu mediocris) during the day, dissipating in the evening. Overcast low stratus (option D) is associated with stable, moist air at low levels, common in autumn or maritime high-pressure situations. Nimbostratus (option B) is associated with frontal systems. Squall lines and thunderstorms (option A) require convective instability and moisture not typical of settled high-pressure conditions. #### Source - [?] Source non identifiée ### Q182: The symbol marked (1) in the figure represents which frontal type? ^t50q182 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q182) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q182) ![](figures/t50_q182.png) - **A)** Warm front. - **B)** Front aloft. - **C)** Cold front. - **D)** Occlusion. #### Answer C) #### Explanation On a surface weather chart, a cold front is depicted by a line with solid triangular spikes (barbs) pointing in the direction of movement. The symbol labeled (1) in figure matches the cold front symbol. A warm front uses semicircles. An occlusion uses alternating triangles and semicircles. A front aloft is depicted differently and is less commonly shown on basic surface charts. #### Source - [?] Source non identifiée ### Q183: In METAR code, which identifier denotes heavy rain? ^t50q183 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q183) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q183) - **A)** .+SHRA. - **B)** RA. - **C)** .+RA - **D)** SHRA #### Answer C) #### Explanation In METAR codes, precipitation intensity is indicated by a '+' prefix (heavy) or '-' prefix (light); no prefix means moderate. Rain is coded 'RA'. Therefore heavy rain is '+RA' (written as '+RA' in the standard, shown in the options as '.+RA'). 'RA' alone (option B) means moderate rain. 'SHRA' (option D) means shower of rain (moderate). '+SHRA' (option A) means heavy shower of rain — a convective shower, not continuous heavy rain. #### Key Terms METAR = Aerodrome routine weather report #### Source - [?] Source non identifiée ### Q184: During which stage of a thunderstorm do strong updrafts and downdrafts coexist? ^t50q184 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q184) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q184) - A) Thunderstorm stage. - B) Dissipating stage. - C) Mature stage. - D) Initial stage. #### Answer C) #### Explanation In the mature stage of a thunderstorm, both strong updrafts (sustaining the storm) and strong downdrafts (driven by precipitation drag and evaporative cooling) coexist simultaneously within the Cumulonimbus cell. The initial (cumulus) stage has only updrafts. The dissipating stage is dominated by downdrafts only, which cut off the updraft supply and weaken the storm. 'Thunderstorm stage' (option A) is not a recognised meteorological term. #### Source - [?] Source non identifiée ### Q185: Which conditions are most conducive to aircraft icing? ^t50q185 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q185) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q185) - **A)** Temperatures between +10° C and -30° C in the presence of hail - **B)** Temperatures between 0° C and -12° C with supercooled water droplets present - **C)** Temperatures between -20° C and -40° C within cirrus clouds containing ice crystals - **D)** Sub-zero temperatures with strong wind and cloudless skies #### Answer B) #### Explanation The most severe icing occurs between 0°C and -12°C where supercooled liquid water droplets are most abundant and drop size is largest, producing clear or mixed icing on airframe surfaces. Below -20°C, cloud water is mostly in ice crystal form and causes much less accretion. Above 0°C, droplets are not supercooled and do not freeze on contact. Icing in clear air (option D) does not occur as there are no supercooled droplets. Cirrus (option C) contains ice crystals which do not adhere significantly. #### Source - [?] Source non identifiée ### Q186: What is the primary hazard when approaching a valley airfield with strong winds aloft blowing perpendicular to the surrounding ridges? ^t50q186 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q186) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q186) - **A)** Heavy downdrafts beneath thunderstorm rainfall areas - **B)** Wind shear during descent, with possible 180° wind direction changes - **C)** Reduced visibility and potential loss of sight of the airfield on final - **D)** Formation of moderate to severe clear ice on all aircraft surfaces #### Answer B) #### Explanation When strong wind blows perpendicular to a mountain ridge, orographic lift on the windward side and mechanical turbulence create complex wind shear on the lee side. An aircraft descending into a valley airfield on the lee side may encounter severe wind shear with the wind reversing by up to 180° between altitudes, creating sudden loss of airspeed or ground wind opposite to the upper-level flow. Reduced visibility (option C) is a secondary concern. Icing (option D) is unrelated to mountain wind shear. Heavy downdrafts in rainfall (option A) describes thunderstorm activity, not orographic flow. #### Source - [?] Source non identifiée ### Q187: What are "blue thermals"? ^t50q187 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q187) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q187) - **A)** Turbulence in the vicinity of cumulonimbus clouds - **B)** Descending air found between cumulus clouds - **C)** Thermals that rise without producing any cumulus clouds - **D)** Thermals occurring when cumulus coverage is below 4/8 #### Answer C) #### Explanation Blue thermals are thermals that extend to significant altitude but remain below the condensation level (dew point height), so no Cumulus clouds form — the sky appears clear (blue). They are invisible to glider pilots and require instruments or experience to exploit. - **Option D** confuses thermals with cloud coverage statistics. - **Option B** describes sink between Cu clouds. - **Option A** describes clear-air turbulence (CAT) near thunderstorms, a different phenomenon. #### Source - [VV Q127 p.133](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=133) (score: 0.20) - PDF Answer: B ### Q188: The expression "beginning of thermals" refers to the moment when thermal strength ^t50q188 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q188) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q188) - **A)** Is sufficient for cross-country soaring with cumulus clouds marking the thermals. - **B)** Reaches at least 1200 m MSL and becomes usable for gliding. - **C)** Becomes sufficient for gliding and extends to at least 600 m AGL. - **D)** Reaches at least 600 m AGL and produces cumulus clouds. #### Answer C) #### Explanation The 'beginning of thermals' (Thermikbeginn) is the moment when thermal lift becomes sufficiently strong and deep (reaching at least 600 m AGL) for a glider to sustain flight and gain height — this is the practical definition. It does not require Cu cloud formation (option A), nor does it specify a fixed MSL altitude (option B). - **Option D** adds an unnecessary cloud formation criterion to what is fundamentally an altitude threshold. #### Key Terms - **AGL** = Above Ground Level - **MSL** = Mean Sea Level #### Source - [?] Source non identifiée ### Q189: How is the "trigger temperature" defined? It is the temperature which ^t50q189 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q189) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q189) - A) A thermal reaches during its ascent at the moment cumulus clouds begin forming. - B) Must be attained at ground level for cumulus clouds to develop from thermal convection. - C) Represents the maximum surface temperature achievable before a cumulus cloud evolves into a thunderstorm. - D) Represents the minimum surface temperature required for a cumulus to develop into a thunderstorm. #### Answer B) #### Explanation The trigger temperature is the minimum ground temperature that must be reached before thermals are strong enough to carry air parcels to the condensation level and form Cumulus clouds. It is found on a tephigram or skew-T diagram by tracing the dry adiabatic lapse rate from the surface intersection until it meets the temperature profile. - **Options A and C** misstate it as a temperature reached aloft or a threshold for thunderstorm formation. - **Option D** describes thunderstorm formation, not Cu formation. #### Source - [?] Source non identifiée ### Q190: In a weather briefing, what does the term "over-development" refer to? ^t50q190 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q190) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q190) - **A)** Transition from blue thermals to cloud-marked thermals during the afternoon - **B)** Spreading of cumulus clouds beneath an inversion layer - **C)** Vertical growth of cumulus clouds into rain-producing showers - **D)** Intensification of a thermal low into a storm depression #### Answer C) #### Explanation Over-development (Überentwicklung) occurs when Cumulus clouds develop vertically beyond Cu congestus into rain-producing Cumulonimbus clouds, generating showers and thunderstorms. This typically happens in the afternoon when the atmosphere becomes increasingly unstable. - **Option A** describes a change in thermal visibility. - **Option D** refers to synoptic-scale deepening of depressions. - **Option B** describes the spreading of Cu under an inversion (which is actually 'street' or 'cover' formation, a separate phenomenon). #### Source - [?] Source non identifiée ### Q191: In gliding meteorology, what does "shielding" refer to? ^t50q191 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q191) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q191) - **A)** The anvil-shaped structure at the top of a thunderstorm cloud - **B)** Cumulus cloud coverage expressed in eighths of the sky - **C)** High or mid-level cloud layers that suppress thermal activity - **D)** Nimbostratus covering the windward slope of a mountain range #### Answer C) #### Explanation Shielding (Abschirmung) refers to a layer of high or mid-level cloud (such as Cirrostratus, Altostratus, or Altocumulus) that intercepts solar radiation before it reaches the ground, thus reducing or suppressing the surface heating required for thermal development. - **Option D** describes cloud cover on a windward mountain slope. - **Option A** describes the anvil of a Cb, not shielding. - **Option B** describes sky coverage in oktas, which is unrelated. #### Source - [?] Source non identifiée ### Q192: What is the gaseous composition of dry air? ^t50q192 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q192) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q192) - **A)** Oxygen 21%, Nitrogen 78%, Noble gases / carbon dioxide 1% - **B)** Nitrogen 21%, Oxygen 78%, Noble gases / carbon dioxide 1% - **C)** Oxygen 21%, Water vapour 78%, Noble gases / carbon dioxide 1% - **D)** Oxygen 78%, Water vapour 21%, Nitrogen 1% #### Answer A) #### Explanation Dry air is composed of approximately 78% nitrogen, 21% oxygen, and 1% argon and trace gases including carbon dioxide. This is the standard atmospheric composition. All other options incorrectly swap the proportions of nitrogen and oxygen or introduce water vapour as a major component. Water vapour is a variable constituent (0–4%) not included in the standard dry air composition. #### Source - [VV Q8 p.108](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=108) (score: 0.41) - [QuizVDS Q11](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q11): Answer B - PDF Answer: D ### Q193: Under ISA conditions at mean sea level, what is the mass of one cubic metre of air? ^t50q193 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q193) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q193) - **A)** 12,25 kg - **B)** 0,01225 kg - **C)** 1,225 kg - **D)** 0,1225 kg #### Answer C) #### Explanation At MSL under ISA conditions, the standard air density is 1.225 kg/m³. A cube with 1 m edges has a volume of 1 m³, so its mass is 1.225 kg. - **Option B** (0.01225 kg) is off by a factor of 100, option D (0.1225 kg) by a factor of 10, and option A (12.25 kg) by a factor of 10 in the opposite direction. - These represent common decimal-point errors. #### Key Terms - **ISA** = International Standard Atmosphere - **MSL** = Mean Sea Level #### Source - [?] Source non identifiée ### Q194: How is the tropopause defined? ^t50q194 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q194) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q194) - A) The altitude above which temperature begins to decrease. - B) The boundary between the mesosphere and the stratosphere. - C) The layer above the troposphere where temperature increases. - D) The boundary zone between the troposphere and the stratosphere. #### Answer D) #### Explanation The tropopause is the boundary layer separating the troposphere (where temperature decreases with altitude) from the stratosphere (where temperature is initially constant and then increases due to ozone absorption). It is not the layer above the troposphere (option C), nor the height where temperature starts to decrease (option A — that is the surface of the troposphere). - **Option B** confuses the tropopause with the stratopause. #### Source - [?] Source non identifiée ### Q195: What characterises an inversion layer? ^t50q195 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q195) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q195) - **A)** A boundary zone separating two distinct atmospheric layers - **B)** An atmospheric layer where temperature falls with increasing altitude - **C)** An atmospheric layer where temperature remains constant with increasing altitude - **D)** An atmospheric layer where temperature rises with increasing altitude #### Answer D) #### Explanation An inversion layer is an atmospheric layer in which temperature increases with increasing altitude, the reverse ('inversion') of the normal decrease. Inversions suppress vertical mixing and convection, trapping pollutants and inhibiting thermal development above them. - **Option B** describes normal atmospheric conditions. - **Option C** describes an isothermal layer. - **Option A** describes a generic boundary without specifying the temperature gradient direction. #### Source - [VV Q30 p.113](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=113) (score: 0.30) - [QuizVDS Q121](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q121): Answer C - PDF Answer: D ### Q196: What defines an isothermal layer? ^t50q196 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q196) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q196) - **A)** An atmospheric layer where temperature increases with height - **B)** A transition zone between two other atmospheric layers - **C)** An atmospheric layer where temperature decreases with height - **D)** An atmospheric layer where temperature stays constant with height #### Answer D) #### Explanation An isothermal layer is one in which temperature remains constant with increasing altitude — neither increasing (inversion, option A) nor decreasing (normal lapse rate, option C). Isothermal conditions are found, for example, in the lower stratosphere. - **Option B** describes a generic atmospheric boundary layer, not a layer of constant temperature. #### Source - [VV Q30 p.113](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=113) (score: 0.33) - PDF Answer: D ### Q197: What fundamental force initiates wind? ^t50q197 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q197) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q197) - **A)** Thermal force - **B)** Coriolis force - **C)** Centrifugal force - **D)** Pressure gradient force #### Answer D) #### Explanation Wind is caused by the pressure gradient force — air flows from areas of high pressure to areas of low pressure, and the greater the pressure difference over a given distance, the stronger the resulting wind. The Coriolis force (option B) deflects wind but does not create it. Centrifugal force (option C) is a secondary effect in curved flow. There is no meteorological force specifically called 'thermal force'; thermal differences drive pressure gradients, but the direct cause of wind is the pressure gradient itself. #### Source - [?] Source non identifiée ### Q198: Under what conditions does Foehn typically develop? ^t50q198 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q198) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q198) - **A)** Stability, with extensive airflow forced over a mountain ridge. - **B)** Instability, with a high pressure area and calm wind. - **C)** Stability, with a high pressure area and calm wind. - **D)** Instability, with extensive airflow forced over a mountain ridge. #### Answer A) #### Explanation Foehn develops when a stable airflow is forced over a mountain barrier. On the windward side, the air rises moist-adiabatically (condensation releasing latent heat), and on the lee side it descends dry-adiabatically, arriving warmer and drier than before ascent. Stability is necessary for the organised flow; instability would break the flow into convective cells. Calm high-pressure conditions (options B and C) do not provide the cross-mountain pressure gradient needed. Instability (option D) would prevent the laminar flow characteristic of Foehn. #### Source - [?] Source non identifiée ### Q199: How is the "spread" (dew-point depression) defined? ^t50q199 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q199) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q199) - **A)** The maximum quantity of water vapour that air can hold. - **B)** The ratio of actual humidity to the maximum possible humidity. - **C)** The difference between the actual air temperature and the dew point. - **D)** The difference between the dew point and the condensation point. #### Answer C) #### Explanation The spread (or dew-point spread) is the difference between the actual (dry-bulb) air temperature and the dew point temperature. A small spread indicates air close to saturation; when the spread reaches zero, condensation and fog or cloud formation occur. - **Option D** is incorrect because dew point and condensation point are effectively the same. - **Option B** describes relative humidity. - **Option A** describes the saturation mixing ratio or absolute humidity capacity. #### Source - [?] Source non identifiée ### Q200: During Foehn, what weather phenomenon designated by "2" should be expected on the lee side?. ^t50q200 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q200) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q200) ![](figures/t50_q200.png) - **A)** Altocumulus Castellanus - **B)** Altocumulus lenticularis - **C)** Cumulonimbus - **D)** Nimbostratus #### Answer B) #### Explanation This question is identical in content to question 90. During Foehn, the descending and warming lee-side flow is stable and generates standing wave clouds. Altocumulus lenticularis forms in the crests of these mountain waves on the lee side. Cumulonimbus (options C and D) requires strong convective instability absent in Foehn descent. Altocumulus Castellanus (option A) indicates mid-level instability, not the stable wave motion of a Foehn situation. #### Source - [VV Q70 p.121](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=121) (score: 0.20) - [QuizVDS Q58](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q58): Answer C - PDF Answer: A ### Q201: Which factor can prevent radiation fog from forming? ^t50q201 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q201) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q201) - **A)** Low spread - **B)** Calm wind - **C)** Overcast cloud cover - **D)** Clear night, no clouds #### Answer C) #### Explanation Radiation fog forms on clear, calm nights when the ground radiates heat to space, cooling the surface air to its dew point. An overcast cloud cover prevents the necessary radiative cooling of the ground surface by acting as an insulating blanket, reflecting long-wave radiation back to the ground. Calm wind (option B) is actually a prerequisite for radiation fog formation. A clear night (option D) and low spread (option A) are also favourable, not preventative, conditions. #### Source - [?] Source non identifiée ### Q202: Through what process does advection fog form? ^t50q202 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q202) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q202) - **A)** Extended radiative cooling on clear nights - **B)** Warm, humid air moving across a cold surface - **C)** Mixing of cold, humid air with warm, humid air - **D)** Cold, moist air flowing over warm ground #### Answer B) #### Explanation Advection fog forms when warm, moist air is transported (advected) horizontally over a cold surface and cooled from below to its dew point. This is most common over cold ocean currents or cold land surfaces in spring. - **Option D** reverses the temperature relationship. - **Option C** describes mixing fog (a different type). - **Option A** describes radiation fog. - The defining factor in advection fog is the movement of warm moist air over cold ground. #### Source - [S3 Q12 p.25](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_3.pdf#page=25) (score: 0.25) ### Q203: What process leads to the development of orographic fog (hill fog)? ^t50q203 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q203) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q203) - **A)** Warm, humid air being forced over hills or a mountain range - **B)** Mixing of cold, moist air with warm, moist air - **C)** Extended radiation on cloudless nights - **D)** Evaporation from warm, wet ground into very cold air #### Answer A) #### Explanation Orographic fog (hill fog) forms when moist air is forced to rise over terrain, cooling adiabatically until it reaches its dew point; the result is a cloud base that sits on the hillside or mountain top. - **Option C** describes radiation fog. - **Option D** describes steam fog (evaporation/mixing fog). - **Option B** describes mixing fog. - The key process is forced lifting of moist air over elevated terrain. #### Source - [?] Source non identifiée ### Q204: What weather phenomena are associated with an upper-level trough? ^t50q204 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q204) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q204) - **A)** Development of showers and thunderstorms (Cb) - **B)** Light winds and shallow cumulus formation - **C)** High stratus layers with ground-covering cloud bases - **D)** Calm weather and formation of lifted fog layers #### Answer A) #### Explanation An upper-level trough is a region of cold air aloft with positive vorticity advection, which promotes divergence aloft and convergence at the surface, triggering strong convective uplift. This instability favours the development of showers and thunderstorms (Cumulonimbus). - **Options B and D** describe stable, anticyclonic conditions. - **Option C** (high stratus) would require stable, moist conditions near the surface, not the convective instability associated with a cold upper trough. #### Source - [?] Source non identifiée ### Q205: On the windward side of a mountain range during Foehn, what weather should be expected? ^t50q205 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q205) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q205) - **A)** Cloud dissipation with unusual warming and strong gusty winds - **B)** Layer clouds, mountain peaks obscured, poor visibility, and moderate to heavy rain - **C)** Scattered cumulus with showers and thunderstorms - **D)** Calm winds and formation of high stratus (high fog) #### Answer B) #### Explanation On the windward (stau) side of a mountain range during Foehn, moist air is forced to rise and cool, producing dense cloud, obscured peaks, poor visibility, and moderate to heavy rain or snow — the classic 'Stau' weather. - **Option A** describes the lee side of the Foehn (warm, dry, gusty). - **Option D** describes stable, fog-prone conditions unrelated to Foehn. - **Option C** describes conditions more typical of frontal convective activity. #### Source - [?] Source non identifiée ### Q206: Which chart presents observed MSL pressure distribution and the corresponding frontal systems? ^t50q206 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q206) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q206) - **A)** Significant Weather Chart (SWC). - **B)** Prognostic chart. - **C)** Surface weather chart. - **D)** Hypsometric chart #### Answer C) #### Explanation The surface weather chart (also called the synoptic chart or analysis chart) displays actual measured pressure values reduced to MSL as isobars, along with the positions of frontal systems. It represents the observed state of the atmosphere at a specific time. A prognostic chart (option B) shows forecast conditions. The hypsometric chart (option D) shows upper-level contour heights on constant-pressure surfaces. The SWC (option A) focuses on hazardous weather phenomena, not comprehensive pressure analysis. #### Key Terms MSL = Mean Sea Level #### Source - [?] Source non identifiée ### Q207: In METAR, how is heavy rain encoded? ^t50q207 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q207) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q207) - A) SHRA - B) .+SHRA. - C) .+RA - D) RA. #### Answer C) #### Explanation This question is identical to question 120. In METAR, precipitation intensity modifiers are '+' for heavy and '-' for light. 'RA' is the METAR code for rain; therefore '+RA' (shown as '.+RA' in the options) denotes heavy rain. 'RA' (option D) alone means moderate rain. 'SHRA' (option A) is shower of rain. '+SHRA' (option B) is heavy shower of rain — a different precipitation type. #### Key Terms METAR = Aerodrome routine weather report #### Source - [?] Source non identifiée ### Q208: In METAR, how are moderate rain showers encoded? ^t50q208 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q208) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q208) - A) .+RA. - B) TS. - C) .+TSRA - D) SHRA. #### Answer D) #### Explanation In METAR, the descriptor 'SH' (shower) is added before the precipitation code to indicate convective precipitation from cumuliform clouds. Moderate showers of rain are therefore coded 'SHRA'. '+TSRA' (option C) means heavy thunderstorm with rain. 'TS' (option B) means thunderstorm without precipitation modifier. '+RA' (option A) means heavy continuous rain from stratiform clouds, not a shower. #### Key Terms METAR = Aerodrome routine weather report #### Source - [?] Source non identifiée ### Q209: Under what conditions does back-side weather (Ruckseitenwetter) occur? ^t50q209 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q209) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q209) - A) After the passage of a warm front - B) During Foehn on the lee side - C) After the passage of a cold front - D) Before the passage of an occlusion #### Answer C) #### Explanation Back-side weather (Rückseitenwetter) describes the weather in the cold air mass following the passage of a cold front: cold, unstable polar or arctic air with scattered showers, good visibility, and gusty winds — often excellent soaring conditions for gliders in the convective back-side air. It occurs after, not before, frontal passages. An occlusion (option D) combines warm and cold front characteristics. Foehn (option B) is a separate orographic phenomenon. After a warm front (option A) brings the warm sector, not cold back-side air. #### Source - [?] Source non identifiée ### Q210: In the International Standard Atmosphere, how does temperature change from MSL to approximately 10,000 m altitude? ^t50q210 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q210) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q210) - **A)** From +15° to -50°C - **B)** From -15° to +50°C - **C)** From +30° to -40°C - **D)** From +20° to -40°C #### Answer A) #### Explanation In the International Standard Atmosphere (ISA), the temperature at MSL is +15°C, and the temperature decreases at 6.5°C per 1000 m (2°C per 1000 ft) through the troposphere. At approximately 11,000 m (the tropopause), the temperature reaches -56.5°C, rounding to approximately -50°C at 10,000 m. - **Options C and D** give incorrect MSL starting values (+30°C and +20°C). - **Option B** reverses the sign convention, implying temperature increases with altitude. #### Key Terms - **ISA** = International Standard Atmosphere - **MSL** = Mean Sea Level #### Source - [S2 Q4 p.37](../SOURCES/Examen%20Blanc/Exa%20Blanc%20Série_2.pdf#page=37) (score: 0.33) - [QuizVDS Q127](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q127): Answer D ### Q211: What weather should be expected during Foehn conditions in the Bavarian region near the Alps? ^t50q211 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q211) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q211) - A) Nimbostratus on the northern Alps, rotor clouds on the windward side, warm and dry wind - B) High pressure over the Bay of Biscay and low pressure over Eastern Europe - C) Nimbostratus on the southern Alps, rotor clouds on the lee side, warm and dry wind - D) Cold, humid downslope wind on the lee side of the Alps with a flat pressure pattern #### Answer C) #### Explanation Classic Bavarian Foehn is driven by low pressure over the Gulf of Genoa and high pressure over the North Sea, forcing air southward over the Alps. Nimbostratus forms on the south (windward) side of the Alps, while on the north (lee) Bavarian side, warm and dry air descends, often accompanied by Föhnmauer (Foehn wall) and rotor clouds along the Foehn boundary. - **Option A** incorrectly describes the lee-side wind as cold and humid and places the Ns on the wrong side. - **Option B** describes the synoptic pressure setup only partially. - **Option A** places the Ns on the north (lee) side, which is incorrect. #### Source - [?] Source non identifiée ### Q212: Which meteorological element is most important for the safety of a VFR flight? ^t50q212 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q212) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q212) - A) Wind direction and strength - B) Air temperature - C) Horizontal visibility - D) Amount and height of clouds above 1500 m/GND #### Answer C) #### Explanation For visual flight rules (VFR), horizontal visibility is the most critical element: below the regulatory minimum, the pilot can no longer maintain separation from terrain, obstacles, and other aircraft by sight alone. Wind direction, temperature, and cloud cover above 1500 m are important, but it is low clouds and reduced visibility that directly trigger VFR restrictions. The amount and height of clouds below 1500 m/GND (ceiling) is also critical, as a low ceiling can trap the pilot. --- #### Source - [VV Q1 p.107](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=107) (score: 1.00) - PDF Answer: B ### Q213: Which meteorological situation reduces visibility the most? ^t50q213 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q213) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q213) - A) The approach of a polar air mass - B) High pressure - C) Fog - D) Foehn #### Answer C) #### Explanation Fog can reduce visibility to a few meters, or even less than 100 m, making it by far the most severe visibility reduction in surface meteorology. Foehn is generally associated with excellent visibility. High pressure often favors clear skies, except in winter where inversions can produce fog or stratus. A polar air mass can bring snow showers, but these reduce visibility less drastically than thick fog. --- #### Source - [VV Q3 p.107](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=107) (score: 1.00) - PDF Answer: A ### Q214: From which altitude can the danger of gaseous embolism occur? ^t50q214 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q214) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q214) - A) From 10,000 m/AMSL - B) From 13,000 m/AMSL - C) From 16,000 m/AMSL - D) From 19,000 m/AMSL #### Answer B) #### Explanation Gaseous embolism (blood boiling) occurs when ambient pressure drops below the vapour pressure of human blood (approximately 47 hPa). This corresponds to about 19,000 m under standard conditions, but serious physiological problems related to extreme low pressure (outgassing of tissues) begin to manifest around 13,000 m/AMSL. This is why this altitude is used as the critical danger threshold in aviation regulations. --- #### Source - [VV Q10 p.109](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=109) (score: 0.78) - PDF Answer: B ### Q215: In a mercury barometer, what is found in the tube above the mercury? ^t50q215 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q215) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q215) - A) Air - B) Nitrogen - C) A practically air-free space (Torricelli vacuum) - D) Water vapour #### Answer C) #### Explanation The mercury barometer works thanks to the partial vacuum created at the top of the sealed tube: when the tube is inverted in a mercury trough, atmospheric pressure supports a mercury column of approximately 760 mm, leaving a nearly vacuum space at the top (Torricelli vacuum). If there were air, nitrogen, or significant water vapour pressure, these would oppose the rise of mercury and distort the measurement. --- #### Source - [VV Q11 p.109](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=109) (score: 0.79) - PDF Answer: A ### Q216: Which instrument is used to measure barometric air pressure? ^t50q216 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q216) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q216) - A) The thermometer - B) The mercury barometer - C) The psychrometer - D) The Magdeburg hemispheres #### Answer B) #### Explanation The mercury barometer measures atmospheric pressure by balancing the weight of a mercury column against air pressure. The thermometer measures temperature, the psychrometer measures relative humidity (by the difference between dry-bulb and wet-bulb thermometers), and the Magdeburg hemispheres were a historical demonstration of atmospheric pressure, not a standard measuring instrument. --- #### Source - [VV Q12 p.109](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=109) (score: 0.86) - PDF Answer: A ### Q217: Which instrument is used to measure wind speed at a meteorological station? ^t50q217 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q217) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q217) - A) A weather flag - B) A windsock - C) A rotary cup anemometer - D) A kite #### Answer C) #### Explanation The anemometer (in particular the cup anemometer) is the standard instrument for measuring wind speed at meteorological stations. The windsock and weather flag give approximate visual indications but do not provide precise measurements. Kites were used historically by pioneers such as Benjamin Franklin but are not standard measuring instruments. Ultrasonic and hot-wire anemometers are modern variants. --- #### Source - [VV Q48 p.117](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=117) (score: 0.88) - PDF Answer: D ### Q218: What is the chart commonly used to compile wind statistics for a given location (e.g., an airport)? ^t50q218 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q218) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q218) - A) The wind rose - B) The wind triangle - C) The wind polygon (frequency rose) - D) The isotachs #### Answer C) #### Explanation The wind polygon (frequency rose) shows, for each directional sector, the frequency and average speed of winds observed over a long period at a given location - very useful for planning runway orientation. The wind rose is the figure showing the 16 cardinal and intercardinal directions, but it is not a statistical chart. The wind triangle is an air navigation tool (drift calculation). Isotachs are lines of equal wind speed on a weather chart. --- #### Source - [VV Q51 p.117](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=117) (score: 0.83) - PDF Answer: B ### Q219: What is meant by the "polar front jet stream"? ^t50q219 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q219) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q219) - A) A warm, strong ascending current ahead of the polar front - B) A zone of strong surface wind parallel to the polar front - C) A zone of very strong wind at the boundary of the tropopause - D) A strong descending wind after the passage of the polar front #### Answer C) #### Explanation The polar jet stream is a band of very strong winds (often 100-300 km/h) that forms at the boundary between cold polar air and warm subtropical air, in the upper troposphere (approximately 8-12 km altitude), near the tropopause. It results from the strong horizontal temperature gradient between these air masses. Its effect on the upper-level pressure gradient is significant and it guides the track of depressions at our latitudes. --- #### Source - [VV Q57 p.119](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=119) (score: 0.58) - PDF Answer: C ### Q220: At what height above an obstacle are mechanical turbulences strongest? ^t50q220 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q220) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q220) - A) 150 m/AGL (above the obstacle) - B) 500 m/AGL - C) 1000 m/AGL - D) 2000 m/AGL #### Answer A) #### Explanation Mechanical turbulence generated by airflow around an obstacle (building, tree, hill) is most intense in the immediate downstream zone, up to approximately 150 m above the top of the obstacle. In this zone, eddies and wind shear are at a maximum. Beyond this, turbulence gradually decreases with altitude. For approach and landing, it is therefore recommended to maintain a minimum altitude margin of 150 m above obstacles upstream of the runway. --- #### Source - [VV Q58 p.119](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=119) (score: 0.92) - PDF Answer: B ### Q221: Under which conditions do the strongest thermal and mechanical turbulences occur at noon? ^t50q221 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q221) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q221) - A) Calm wind, hilly region, clear sky - B) Calm wind, flat region, 5/8 Cu - C) 25 kt wind, hilly region, clear sky - D) 25 kt wind, hilly region, 5/8 Cu #### Answer D) #### Explanation The strongest turbulence results from the combination of thermal and mechanical effects: strong wind (25 kt) generates significant mechanical turbulence over hilly terrain. The presence of 5/8 cumulus indicates active thermal convection. This combination - strong wind plus relief plus convection - produces turbulence far exceeding what either factor alone would generate. Calm wind produces only weak thermals, and a clear sky with strong wind gives mainly mechanical turbulence without thermal reinforcement. --- #### Source - [VV Q59 p.119](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=119) (score: 0.86) - PDF Answer: B ### Q222: When is water described as supercooled in a cloud? ^t50q222 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q222) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q222) - A) When the cloud produces snow - B) When the cloud contains ice crystals - C) When water droplets remain liquid below 0°C - D) When the water temperature is around 0°C #### Answer C) #### Explanation Supercooled water is liquid water that remains in liquid state even when its temperature is below 0°C (down to approximately -40°C). This is possible because very pure droplets suspended in clouds lack freezing nuclei. Supercooled water is particularly dangerous for aviation because it freezes instantly on contact with the cold surface of an aircraft, producing rime or clear ice. It is encountered mainly in cumulus, altocumulus, and nimbostratus between 0°C and -20°C. --- #### Source - [VV Q60 p.119](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=119) (score: 0.72) - PDF Answer: A ### Q223: What is the width of the precipitation zone in a cold front? ^t50q223 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q223) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q223) - A) 10-30 km - B) 90-100 km - C) 150-300 km - D) 500-1000 km #### Answer B) #### Explanation The precipitation zone associated with a cold front is narrow (approximately 90-100 km) but intense: the cold front advances rapidly, forcing warm air to rise violently. This produces cumulonimbus clouds with heavy showers, thunderstorms, and sometimes hail. In contrast, the warm front has a much wider precipitation zone (150-300 km) but more continuous and less intense. This width difference explains why cold front disturbances are brief and violent, while warm front ones are long and gradual. --- #### Source - [VV Q96 p.127](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=127) (score: 1.00) - PDF Answer: D ### Q224: How does visibility change when flying VFR from a cold air sector toward a warm front? ^t50q224 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q224) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q224) - A) Visibility improves - B) Visibility deteriorates - C) Visibility remains the same - D) None of the answers is valid #### Answer B) #### Explanation Advancing from cold air (polar air mass with good visibility) toward a warm front, the pilot encounters a progressive deterioration: cirrus thickens to cirrostratus, then altostratus, the ceiling lowers, and precipitation begins (rain or drizzle). Visibility deteriorates as the cloud layer thickens and precipitation becomes continuous. This gradual degradation gradient is a typical characteristic of warm front approach, in contrast to the cold front which abruptly deteriorates then rapidly improves conditions. --- #### Source - [VV Q97 p.127](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=127) (score: 0.94) - PDF Answer: C ### Q225: What is the width of the precipitation zone in a warm front? ^t50q225 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q225) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q225) - A) 10-30 km - B) 80-100 km - C) 150-300 km - D) 500-1000 km #### Answer C) #### Explanation The warm front is characterized by a gently sloping frontal surface (approximately 1:100 to 1:150), meaning warm air rises very gradually over cold air across a large horizontal distance. This creates a wide precipitation band (150-300 km) extending well ahead of the surface front position. Precipitation is generally continuous, less intense than for a cold front, and accompanied by nimbostratus and altostratus. --- #### Source - [VV Q98 p.127](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=127) (score: 1.00) - PDF Answer: A ### Q226: How does the cloud base change when flying VFR from a cold air sector toward a warm front? ^t50q226 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q226) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q226) - A) The cloud base drops suddenly - B) The cloud base drops gradually - C) The cloud base rises suddenly - D) The cloud base rises gradually #### Answer B) #### Explanation Approaching a warm front, the typical cloud sequence begins with high-altitude cirrus (very high base), followed by cirrostratus, altostratus, and then nimbostratus whose base can be very low (a few hundred metres). This ceiling drops gradually as the pilot approaches the front - a progressive warning that allows time to react, in contrast to the cold front which abruptly deteriorates conditions. --- #### Source - [VV Q99 p.127](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=127) (score: 0.94) - PDF Answer: D ### Q227: Which zone of an occlusion is most active? ^t50q227 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q227) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q227) - A) The zone away from where the warm and cold fronts meet - B) The zone near where the warm and cold fronts meet (triple point) - C) The occlusion produces the same activity throughout its length - D) None of the answers is valid #### Answer B) #### Explanation An occlusion forms when the cold front, which advances faster, catches up with the warm front and lifts the warm sector off the ground. The most active zone - with the strongest winds, most intense precipitation, and most likely thunderstorms - is near the triple point (occlusion point), where both fronts meet and available energy is at its maximum. At the extremities of the occlusion, activity decreases progressively. --- #### Source - [VV Q100 p.128](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=128) (score: 0.82) - PDF Answer: C ### Q228: When is the term "mist" used? ^t50q228 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q228) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q228) - A) Visibility is between 1000 and 8000 m - B) Visibility is between 1000 and 5000 m - C) Visibility is between 1000 and 3000 m - D) Visibility is below 1000 m #### Answer A) #### Explanation By international meteorological convention, mist is reported when visibility is between 1000 m and 8000 m due to the presence of fine water droplets or ice crystals in suspension. Below 1000 m visibility caused by condensed water vapour, the phenomenon is called fog. Above 8000 m, visibility is considered good. This distinction is important for METARs and VFR conditions. --- #### Source - [VV Q102 p.128](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=128) (score: 1.00) - PDF Answer: C ### Q229: How do temperature, dew point, and relative humidity behave in fog? ^t50q229 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q229) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q229) - A) High relative humidity but temperature remains well above dew point - B) Low relative humidity and temperature far from dew point - C) Temperature equals dew point and relative humidity is equal to or close to 100% - D) Temperature, relative humidity, and dew point are all three equal to each other #### Answer C) #### Explanation Fog forms when air is saturated, i.e., when air temperature drops to the dew point (or humidity increases to saturation). At this point, relative humidity reaches 100% and water vapour begins to condense into fine suspended droplets. Temperature and dew point therefore become practically equal, while relative humidity approaches 100%. Option D is incorrect because relative humidity is a different quantity from temperature. --- #### Source - [VV Q104 p.129](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=129) (score: 0.65) - [QuizVDS Q46](../SOURCES/QuizVDS/50%20-%20Meteorology.md#^q46): Answer B - PDF Answer: B ### Q230: What are the different stages of a thunderstorm cloud? ^t50q230 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q230) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q230) - A) Build-up, mature, dissipation - B) Cumulus, cumulonimbus, rain - C) Beginning, cumulonimbus, dissolution - D) Early stage, middle stage, final stage #### Answer A) #### Explanation A cumulonimbus (thunderstorm cloud) passes through three well-defined stages. The build-up stage (or cumulus stage): dominant updrafts, the cell grows upward. The mature stage (stabilisation): intense updrafts and downdrafts coexist - this is the most dangerous stage with lightning, hail, violent gusts, and heavy precipitation. The dissipation stage: downdrafts dominate, the cloud gradually evaporates and the thunderstorm weakens. --- #### Source - [VV Q108 p.129](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=129) (score: 1.00) - PDF Answer: B ### Q231: What effect does icing have on a glider passing through cold precipitation? ^t50q231 [DE](../SPL%20Exam%20Questions%20DE/50%20-%20Meteorologie.md#^t50q231) · [FR](../SPL%20Exam%20Questions%20FR/50%20-%20M%C3%A9t%C3%A9orologie.md#^t50q231) - A) Carburetor icing only - B) No consequence on aerodynamic performance - C) Within minutes, the glider can lose the ability to fly - D) Only minor consequences due to weight overload #### Answer C) #### Explanation Icing is particularly critical for gliders: their performance depends on a very precise wing profile with thin margins. Ice accumulating on the leading edge deforms the aerofoil profile, increases drag and reduces lift, lowers the stall speed, and adds weight. These combined effects can make the aircraft uncontrollable within minutes. Unlike powered aircraft, gliders generally have no anti-icing systems, making them extremely vulnerable. Preventive avoidance is the only effective measure. #### Source - [VV Q114 p.131](../SOURCES/VV/Questionnaire%20toutes%20branches%20VV.pdf#page=131) (score: 0.80) - PDF Answer: D