TrueHeading
Log inEnrol
DGCA Aviation Meteorology · 71 questions

Winds & Upper Winds: DGCA Aviation Meteorology Questions and Answers

71 practice questions on Winds & Upper Winds with answers and explanations, plus the key concepts and formulas, from the TrueHeading question bank.

Practise all 71 questionsFlashcards

About this topic

Use this page to revise Winds & Upper Winds for the DGCA Aviation Meteorology paper. Below are the key ideas first, then 12 practice questions with answers and explanations, picked from the 71 questions in the TrueHeading bank for this topic.

In short: The wind balanced between the pressure gradient force and the Coriolis force, blowing parallel to straight isobars.

Open the full set in the student zone to answer every question, track your accuracy and take timed mock tests.

Key concepts: Winds & Upper Winds

8 ideas to know cold.

What is the geostrophic wind and when does it apply?

The wind balanced between the pressure gradient force and the Coriolis force, blowing parallel to straight isobars.

Vg=12Ωρsin⁡ϕ ΔpΔnV_g=\frac{1}{2\Omega\rho\sin\phi}\,\frac{\Delta p}{\Delta n}
  • Closer isobars: stronger wind
  • Speed is inversely proportional to sin latitude and density
  • Not valid near the equator (within about 15°)
LWindPGFCoriolisNorthern hemisphere: wind blows anticlockwise round a lowBuys Ballot: back to the wind,low pressure is on your left

Buys Ballot’s law?

In the northern hemisphere, stand with your back to the wind: low pressure is on your left.

Tip: Opposite in the southern hemisphere.

What does friction do to the surface wind?

It slows the wind and backs it (northern hemisphere) relative to the geostrophic wind.

  • Over land: about 30° backing, speed 40–50 % of geostrophic
  • Over sea: about 10–15° backing, speed about 70 %
  • Winds veer with height up to the gradient level (about 2000 ft)

Gradient wind versus geostrophic?

Gradient wind includes the effect of curved isobars.

  • Around a low: gradient wind is weaker than geostrophic (sub-geostrophic)
  • Around a high: stronger (super-geostrophic)

What is the thermal wind?

The change in geostrophic wind with height caused by a horizontal temperature gradient.

  • It blows parallel to the isotherms with the cold air on the left (northern hemisphere)
  • Explains why westerlies strengthen with height in mid-latitudes

Sea breeze and land breeze?

Sea breeze: by day, from sea to land (land heats faster). Land breeze: at night, from land to sea.

  • Sea breeze is stronger and may reach 10–15 kt in the afternoon
  • Anabatic wind blows up a sunny slope, katabatic wind flows down a cold slope at night

What is the geostrophic wind?

The wind that blows parallel to the isobars when the pressure gradient force balances the Coriolis force.

Vg=12Ωρsin⁡ϕΔpΔnV_g=\dfrac{1}{2\Omega\rho\sin\phi}\dfrac{\Delta p}{\Delta n}
  • Geostrophic speed ∝ gradient / (ρ sin latitude)
  • No geostrophic wind at the equator
  • Thermal wind: wind shear due to horizontal temperature differences, blows with cold air to the left (N)

What is the Coriolis force?

An apparent force due to the Earth's rotation. It deflects moving air to the right in the northern hemisphere and to the left in the southern.

  • Proportional to wind speed and sin(latitude)
  • Zero at the equator
  • Acts at 90° to the wind

Practice questions: Winds & Upper Winds

Tap “Show answer” after you have tried each one.

Q1Compared with the geostrophic wind, the surface wind over land is:

  1. stronger and veered
  2. weaker and veered
  3. the same
  4. weaker and backed (turned toward low pressure)
Show answer

Answer: D. weaker and backed (turned toward low pressure)

Friction reduces speed and the Coriolis force; the wind crosses the isobars toward low pressure at about 30° over land.

Q2When climbing from the surface to the gradient level in the northern hemisphere, the wind direction usually:

  1. veers (turns clockwise)
  2. reverses direction
  3. backs (turns anticlockwise)
  4. does not change
Show answer

Answer: A. veers (turns clockwise)

Friction decreases with height, so the wind turns toward the geostrophic direction.

Q3The Coriolis force is greatest at:

  1. the equator
  2. the poles
  3. 30° latitude
  4. it is the same everywhere
Show answer

Answer: B. the poles

The Coriolis parameter is proportional to sin(latitude): zero at the equator and maximum at the poles.

Q4At the equator the geostrophic wind approximation:

  1. breaks down because the Coriolis force is zero
  2. is replaced by the thermal wind
  3. is most accurate
  4. applies only to jet streams
Show answer

Answer: A. breaks down because the Coriolis force is zero

Near the equator winds blow more directly across the isobars.

Q5The thermal wind blows:

  1. from cold to warm
  2. across the isotherms
  3. parallel to the isotherms, with cold air on the left in the northern hemisphere
  4. from warm to cold air
Show answer

Answer: C. parallel to the isotherms, with cold air on the left in the northern hemisphere

It is the vector difference between the geostrophic winds at two levels.

Q6The wind speed of the thermal wind increases with:

  1. the humidity
  2. the wind direction
  3. the pressure at the surface
  4. the horizontal temperature gradient
Show answer

Answer: D. the horizontal temperature gradient

Larger temperature gradient means larger thermal wind.

Q7Anabatic winds are:

  1. upslope winds caused by heated slopes
  2. winds along a coast
  3. downslope winds at night
  4. winds associated with fronts
Show answer

Answer: A. upslope winds caused by heated slopes

Katabatic winds flow down cooled slopes at night.

Q8Lenticular clouds indicate:

  1. mountain waves
  2. frontal activity
  3. thunderstorms
  4. radiation fog
Show answer

Answer: A. mountain waves

Smooth, lens-shaped clouds mark the crests of standing waves; strong turbulence may exist in the rotor beneath.

Q9The strongest turbulence in mountain waves is usually found:

  1. on the windward side
  2. in the rotor zone under the wave crests and in the lee of the mountain
  3. above the highest peak only
  4. at the tropopause only
Show answer

Answer: B. in the rotor zone under the wave crests and in the lee of the mountain

Rotor clouds mark severe turbulence.

Q10In mid-latitudes the prevailing upper winds are:

  1. northerlies
  2. westerlies
  3. easterlies
  4. southerlies
Show answer

Answer: B. westerlies

Thermal wind balance produces westerlies aloft in both hemispheres.

Q11Gusts are more pronounced:

  1. at night with clear skies
  2. over rough terrain in unstable air
  3. in a ground inversion
  4. over the sea in stable air
Show answer

Answer: B. over rough terrain in unstable air

Turbulent eddies mix momentum downward from stronger winds aloft.

Q12Winds reported to ATC for take-off and landing are given relative to:

  1. compass north
  2. grid north
  3. magnetic north
  4. true north
Show answer

Answer: C. magnetic north

Surface winds from ATC/ATIS are magnetic; METAR winds are true.

Practise all 71 questionsTake a Meteorology mock test

More DGCA Aviation Meteorology topics

Atmosphere & ISA125 QPressure & Altimetry103 QTemperature, Humidity & Cloud Base94 QStability & Adiabatics71 QPressure Systems & Depressions27 QJet Streams27 QClouds, Fog & Precipitation92 QFronts & Air Masses48 QThunderstorms, Turbulence & Windshear66 QIcing42 QTropical Cyclones15 QClimatology & Monsoon32 QWeather Reports & Charts113 QMeteorological Calculations174 Q
All DGCA questionsCPL exam syllabusHow to prepareAviation Meteorology formulas

Learn Aviation Meteorology one-on-one with Nikunj

Unlimited personal sessions, weekly subject tests and lifetime access to the student website. First-attempt pass guarantee, or your money back.

Enquire & enrolDGCA Aviation Meteorology classes
Call WhatsApp