Meteorology practice test

Free test · Meteorology · DGCA CPL and ATPL

Three chapter tests and one mixed paper across the whole syllabus, each answer explained. No sign-in needed.

Quick test

Chapter 1

10 questions to check this chapter. Each answer explains why.

  1. An airliner climbs out of Chennai into a cloudless sky and levels at FL370. In which layer is it cruising?

    • Troposphere
    • Mesosphere
    • Stratosphere

    Answer: Troposphere. Over the tropics the tropopause is near 16-17 km (FL520-560), so FL370 is still well inside the troposphere.

  2. Why is the tropopause highest over the equator?

    • Coriolis force is strongest there
    • Strong heating and convection lift the whole column
    • The air there is coldest

    Answer: Strong heating and convection lift the whole column. Vigorous convection over the warm tropics carries the troposphere's top up to 16-18 km; over the poles it sits near 8 km.

  3. Climbing through the stratosphere, the temperature

    • stays the same, then rises
    • keeps falling at 6.5 °C/km
    • rises at once, then falls

    Answer: stays the same, then rises. In the ISA it stays at −56.5 °C to 20 km, then ozone heating makes it rise towards the stratopause.

  4. Which gas absorbs most of the sun's ultraviolet and warms the stratosphere?

    • Nitrogen
    • Carbon dioxide
    • Ozone

    Answer: Ozone. Ozone, densest at about 20-25 km, soaks up UV and heats the layer around it.

  5. Almost all of the atmosphere's water vapour is found

    • in the troposphere
    • in the stratosphere
    • spread evenly to 50 km

    Answer: in the troposphere. Vapour comes from the surface and condenses out as it rises, so nearly all of it, and all the weather, stays low.

  6. An OAT gauge reads +5 °C at 6000 ft. The ISA deviation is

    • +2 °C
    • −8 °C
    • +8 °C

    Answer: +2 °C. ISA at 6000 ft is 15 − 2 × 6 = +3 °C; actual minus ISA is 5 − 3 = +2 °C.

  7. A sea-level airfield reports exactly standard conditions. The METAR shows

    • 20 °C and Q1013
    • 15 °C and Q1013
    • 0 °C and Q1000

    Answer: 15 °C and Q1013. The ISA starts at 15 °C and 1013.25 hPa at mean sea level.

  8. Dust, smoke and salt in the air matter to pilots mainly because they

    • cut visibility and help fog form
    • warm the stratosphere
    • make the air heavier

    Answer: cut visibility and help fog form. Particles scatter light and act as nuclei for condensation, so cities and dusty plains get haze, smog and early fog.

  9. Flying at FL450, the outside air temperature in the ISA would be

    • −75 °C
    • −45 °C
    • −56.5 °C

    Answer: −56.5 °C. The ISA lapse rate stops at the tropopause (11 km, about 36,000 ft); above it the temperature stays at −56.5 °C.

  10. In which layer do meteors burn up and noctilucent clouds glow?

    • Mesosphere
    • Troposphere
    • Thermosphere

    Answer: Mesosphere. The mesosphere (about 50-85 km) is the coldest layer; meteors burn there and rare noctilucent clouds form near its top.

Quick test

Chapter 2

10 questions to check this chapter. Each answer explains why.

  1. Leaving Ahmedabad (QNH 1016) for a field with QNH 1004, you forget to reset the altimeter. On arrival it shows

    • less than your true height
    • your true height
    • more than your true height

    Answer: more than your true height. Into lower pressure the reading is too high: you are lower than it says.

  2. On the ground at an airfield, which setting makes the altimeter read the airfield's elevation?

    • QNH
    • 1013.25 hPa
    • QFE

    Answer: QNH. QNH is the pressure reduced to mean sea level, so on the ground the altimeter shows height above the sea: the elevation.

  3. Near sea level, roughly how much does pressure fall for each 30 ft you climb?

    • 1 hPa
    • 0.1 hPa
    • 10 hPa

    Answer: 1 hPa. About 1 hPa per 27-30 ft near the surface; the drop gets smaller with height as the air thins.

  4. Two balloons rise from Leh in January and Chennai in May. Over which does the pressure drop off faster in the first kilometre?

    • Chennai, in the warm air
    • Leh, in the cold air
    • The same over both

    Answer: Leh, in the cold air. Cold air is dense, so its pressure levels are packed close together.

  5. An aircraft holds FL100 all the way from Delhi into a much colder air mass over the Himalaya. Its true altitude

    • rises
    • falls
    • does not change

    Answer: falls. Over cold air the 'FL100' pressure level sits lower, so the aircraft descends with it while the altimeter reads the same.

  6. Climbing out on QNH, you set 1013.25 hPa

    • at the transition altitude
    • at 1000 ft
    • at the transition level

    Answer: at the transition altitude. Climbing, you change to standard at the transition altitude; descending, you change to QNH at the transition level.

  7. QFE is the pressure

    • at the airfield, so the altimeter reads zero on the ground
    • of the standard atmosphere
    • reduced to sea level

    Answer: at the airfield, so the altimeter reads zero on the ground. With QFE set, the altimeter shows height above the airfield.

  8. At a coastal airfield at sea level, how do QNH and QFE compare?

    • They are the same
    • QFE is 10 hPa higher
    • QNH is always 1013

    Answer: They are the same. At sea level there is no height to correct for, so the airfield pressure and the sea-level pressure are the same.

  9. The small twice-daily rise and fall of pressure in the tropics peaks at about

    • 6 am and 6 pm
    • 10 am and 10 pm
    • noon and midnight

    Answer: 10 am and 10 pm. The semi-diurnal wave has highs near 10 and 22 local time and lows near 04 and 16; it is clearest in the tropics.

  10. A forecaster draws smooth lines through every station reporting 1008 hPa, 1012 hPa and so on. She is drawing

    • isobars
    • isallobars
    • isotherms

    Answer: isobars. Isobars connect equal pressure; isotherms connect equal temperature and isallobars equal pressure change.

Quick test

Chapter 3

10 questions to check this chapter. Each answer explains why.

  1. A clear, calm winter night in Lucknow. When is the temperature usually lowest?

    • At sunset
    • Around midnight
    • Just after sunrise

    Answer: Just after sunrise. The ground keeps losing heat until the morning sun outweighs it, so the minimum comes shortly after dawn.

  2. Why is the daily temperature range small on a cloudy day?

    • Cloud stops the wind
    • Cloud blocks sunshine by day and holds heat in at night
    • Cloud makes the air drier

    Answer: Cloud blocks sunshine by day and holds heat in at night. Cloud cuts the day's heating and sends long-wave heat back down at night, so both extremes are trimmed.

  3. Which station would show the biggest gap between the afternoon high and the dawn low in May?

    • Port Blair
    • Jaisalmer
    • Kochi

    Answer: Jaisalmer. Dry desert air and sand heat fast by day and lose heat fast at night; the sea and moist air damp the swing.

  4. Surface air temperature is measured

    • on the runway surface
    • at 10 m on the wind mast
    • in a ventilated screen about 1.25-2 m above grass

    Answer: in a ventilated screen about 1.25-2 m above grass. A white louvred screen in the shade gives the true air temperature, not the temperature of sunlit surfaces.

  5. −40 °C on a thermometer is the same as

    • −40 °F
    • 233 °F
    • −72 °F

    Answer: −40 °F. The Celsius and Fahrenheit scales cross at −40.

  6. How does the Earth's surface mostly send heat back out?

    • By conduction into space
    • As long-wave (infra-red) radiation
    • As short-wave light

    Answer: As long-wave (infra-red) radiation. The cool Earth radiates in the infra-red; the hot sun radiates mostly visible short waves.

  7. Heat carried up by rising thermals is moved by

    • conduction
    • convection
    • radiation

    Answer: convection. Convection moves heat with the moving air; conduction only works where things touch.

  8. About what share of incoming sunlight is reflected straight back to space (the albedo)?

    • About 70%
    • About 30%
    • About 5%

    Answer: About 30%. Clouds, air and the surface together reflect roughly 30 of every 100 units.

  9. Why does land heat up faster than the sea in the afternoon?

    • The sea reflects all sunlight
    • Water mixes and stores heat; land heats only a thin layer
    • Land is closer to the sun

    Answer: Water mixes and stores heat; land heats only a thin layer. Sunlight penetrates water and is spread through a deep, mixing layer with a high specific heat; land heats only its top few centimetres.

  10. When water vapour condenses into cloud, it

    • absorbs heat from the air
    • releases latent heat to the air
    • neither takes nor gives heat

    Answer: releases latent heat to the air. The heat used to evaporate the water is given back on condensation: the fuel of thunderstorms and cyclones.

Mixed practice: test 1

Chapter 30

One question from every chapter, in a mixed order. Each answer names the chapter to revise.

  1. A pilot sees a large ring, always the same size, round the sun through a thin milky veil. The cloud is made of

    • dust
    • water droplets
    • ice crystals

    Answer: ice crystals. A 22° halo comes from refraction in hexagonal ice crystals, typically in cirrostratus. (Revise chapter 10: Optical Phenomena.)

  2. Heavy showers fall from a towering cloud while a few kilometres away the sky is clear. The cloud is

    • cumulonimbus
    • altostratus
    • nimbostratus

    Answer: cumulonimbus. Showers come from convective cloud and fall in shafts; steady rain over wide areas comes from layer cloud. (Revise chapter 11: Precipitation.)

  3. In a METAR, 27015G28KT means

    • wind from 270° at 15 kt, gusting 28 kt
    • wind towards 270°
    • visibility 2700 m

    Answer: wind from 270° at 15 kt, gusting 28 kt. Direction is where the wind comes from; G gives the gusts. (Revise chapter 25: METAR, SPECI and TREND.)

  4. Which three things does a thunderstorm need?

    • Strong wind, cloud and cold air
    • Fog, an inversion and dry air
    • Instability, moisture and a lifting trigger

    Answer: Instability, moisture and a lifting trigger. Without all three the cloud cannot grow tall. (Revise chapter 13: Thunderstorms.)

  5. A cloudless thermal leaves the hot runway at Jodhpur at 40 °C. Without condensing, what will its temperature be 2 km up?

    • About 27 °C
    • About 36 °C
    • About 20 °C

    Answer: About 20 °C. Unsaturated rising air cools at about 9.8 °C per km: 40 − 2 × 9.8 ≈ 20 °C. (Revise chapter 9: Stability.)

  6. Mountain waves need

    • a strong wind across the ridge and a stable layer near the crest
    • a warm front
    • calm air

    Answer: a strong wind across the ridge and a stable layer near the crest. The stable air bounces after crossing the ridge, setting up standing waves downwind. (Revise chapter 17: Mountain Waves.)

  7. North India's winter rain and Himalayan snow come mainly from

    • tropical cyclones
    • western disturbances
    • the south-west monsoon

    Answer: western disturbances. They pass from the west, a few times a month, between December and March. (Revise chapter 19: Climatology of India.)

  8. Which office provides forecasts and briefings for flights from its own airfield?

    • The Aerodrome Meteorological Office (AMO)
    • A radar station
    • The WMO in Geneva

    Answer: The Aerodrome Meteorological Office (AMO). An AMO serves its aerodrome; smaller Aeronautical Met Stations (AMS) mainly observe and report. (Revise chapter 21: Met Services.)

  9. A RAREP is

    • a pilot report
    • a satellite bulletin
    • a radar weather report

    Answer: a radar weather report. It gives the position, extent, intensity, movement and tops of radar echoes. (Revise chapter 27: RAREP, SIGMET and Satellite Bulletin.)

  10. A clear, calm winter night in Lucknow. When is the temperature usually lowest?

    • Just after sunrise
    • At sunset
    • Around midnight

    Answer: Just after sunrise. The ground keeps losing heat until the morning sun outweighs it, so the minimum comes shortly after dawn. (Revise chapter 3: Temperature.)

  11. A clear, calm, moist night after rain at Delhi. Which fog is most likely by dawn?

    • Advection fog
    • Radiation fog
    • Frontal fog

    Answer: Radiation fog. Clear skies let the ground cool, light wind keeps the chilled air in place, and moisture is plentiful. (Revise chapter 7: Visibility and Fog.)

  12. At Delhi the wind is from the east. Using Buys Ballot's rule, where is the lower pressure?

    • To the north
    • To the east
    • To the south

    Answer: To the south. Back to an easterly wind you face west; low pressure is on your left, to the south. (Revise chapter 6: Winds.)

  13. Clear air turbulence is turbulence

    • at high level with no visible cloud
    • inside CB
    • only near the ground

    Answer: at high level with no visible cloud. It comes from strong wind shear, often near jets, and gives no visual warning. (Revise chapter 16: Clear Air Turbulence.)

  14. Air that has spent a week over the warm Arabian Sea before reaching Mumbai would be classed as

    • maritime tropical
    • maritime polar
    • continental polar

    Answer: maritime tropical. A sea source makes it maritime; a warm, low-latitude source makes it tropical. (Revise chapter 14: Air Masses, Fronts and WDs.)

  15. On a T-4, heights are usually given as

    • metres above the airfield
    • pressure in hPa only
    • flight levels

    Answer: flight levels. Cross-sections show the route against flight levels. (Revise chapter 29: T-3 and T-4.)

  16. Tropical cyclones need sea surface temperatures of at least about

    • 15 °C
    • 35 °C
    • 26-27 °C

    Answer: 26-27 °C. Warm water supplies the moisture and latent heat that power the storm. (Revise chapter 18: Tropical Systems and Cyclones.)

  17. Flat-based cumulus at the same height on a summer morning over the plains. The bases mark

    • the tropopause
    • the freezing level
    • the condensation level of the rising thermals

    Answer: the condensation level of the rising thermals. Each thermal cools as it rises and condenses at the same level, giving a common flat base. (Revise chapter 8: Vertical Motion and Clouds.)

  18. Which afternoon gives the longest take-off run for the same aircraft and weight?

    • Leh, 5 °C
    • Leh, 35 °C
    • Mumbai, 35 °C

    Answer: Leh, 35 °C. High and hot together give the highest density altitude: least air for wings, engines and propellers. (Revise chapter 4: Air Density.)

  19. At 0500 the temperature is 24 °C and the dew point 23 °C at Kolkata. What is most likely soon?

    • Mist or fog
    • Clear, dry air
    • A dust storm

    Answer: Mist or fog. With only 1 °C between temperature and dew point, a little more cooling saturates the air. (Revise chapter 5: Humidity.)

  20. On a station model, the circle in the middle shows

    • the pressure
    • the total cloud amount
    • the wind speed

    Answer: the total cloud amount. The fraction filled in gives the cloud cover in oktas. (Revise chapter 24: Station Models.)

  21. A jet stream is a narrow band of strong wind, by convention at least

    • 60 kt
    • 200 kt
    • 20 kt

    Answer: 60 kt. Jets are usually found near the tropopause, often 100-150 kt in the core. (Revise chapter 15: Jet Streams.)

  22. An airliner climbs out of Chennai into a cloudless sky and levels at FL370. In which layer is it cruising?

    • Stratosphere
    • Mesosphere
    • Troposphere

    Answer: Troposphere. Over the tropics the tropopause is near 16-17 km (FL520-560), so FL370 is still well inside the troposphere. (Revise chapter 1: The Atmosphere.)

  23. The tropics receive more radiation than they lose, so the atmosphere and oceans must

    • store heat forever
    • carry heat to the equator
    • carry heat towards the poles

    Answer: carry heat towards the poles. The general circulation moves the surplus poleward. (Revise chapter 20: General Circulation.)

  24. Station pressure is measured with

    • a precision aneroid or mercury barometer
    • a thermometer
    • an anemometer

    Answer: a precision aneroid or mercury barometer. The reading is then reduced to QFE, QNH and QFF. (Revise chapter 23: Met Instruments.)

  25. Before a flight, a crew should get

    • a met briefing or documents covering the route, destination and alternates
    • only the destination METAR
    • nothing if the sky is clear

    Answer: a met briefing or documents covering the route, destination and alternates. Good planning needs the whole picture. (Revise chapter 28: Documentation and Briefing.)

  26. A weather radar sees mainly

    • fog
    • clear air turbulence
    • precipitation

    Answer: precipitation. Radar echoes come from raindrops, hail and snow; small cloud droplets and clear air hardly show. (Revise chapter 22: Radar and Satellites.)

  27. Large supercooled drops striking the wing at −3 °C will most likely form

    • rime ice
    • hoar frost
    • clear (glaze) ice

    Answer: clear (glaze) ice. Big drops freeze slowly, spread back and form heavy, glassy ice that is hard to shed. (Revise chapter 12: Ice Accretion.)

  28. Leaving Ahmedabad (QNH 1016) for a field with QNH 1004, you forget to reset the altimeter. On arrival it shows

    • more than your true height
    • less than your true height
    • your true height

    Answer: more than your true height. Into lower pressure the reading is too high: you are lower than it says. (Revise chapter 2: Pressure and Altimetry.)

  29. A TAF is

    • an observation
    • a forecast for one aerodrome over a stated period
    • a route forecast

    Answer: a forecast for one aerodrome over a stated period. It uses the same codes as a METAR plus change groups. (Revise chapter 26: Aviation Weather Forecasts.)

Takeaway: 29 questions.