Which of the following conditions is most favourable for the formation of a temperature inversion near the ground?
- A.A long, clear and calm winter night
- B.A cloudy and windy summer afternoon
- C.A humid night with strong winds
- D.A hot afternoon over a desert
Correct answer
Explanation
The correct answer is A, a long, clear and calm winter night. An inversion needs the ground to lose heat quickly and the air above to stay undisturbed: a long night gives time for terrestrial radiation to escape, a clear sky lets it escape, dry air absorbs little of it, and calm conditions keep the cold air lying in place, so the layer near the ground becomes colder than the layer above. Option B is wrong because clouds trap outgoing radiation and wind mixes the air, and strong insolation in the afternoon heats the surface instead. Option C fails for the same reason: wind stirs the lower air and moisture holds the heat in. Option D describes the sharpest normal lapse rate rather than an inversion, since the desert surface becomes intensely hot by day. Inversions are commonest in hill valleys, where cold dense air drains down the slopes and pools on the valley floor.
Read the full article: Insolation, Heat Budget and Temperature: Exam Notes
Practice Questions
View allThe incoming solar radiation that reaches the surface of the earth is known as:
- A.Albedo
- B.Insolation
- C.Terrestrial radiation
- D.Isotherm
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The word is a contraction of incoming solar radiation, and it means the short-wave energy from the sun that reaches the earth, measured in India by the India Meteorological Department in units of energy per unit area per unit time.
Read the full explanation →Out of 100 units of insolation received at the top of the atmosphere, how many units are reflected back to space, a share called the albedo of the earth?
- A.14 units
- B.17 units
- C.35 units
- D.51 units
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Of every hundred units of insolation arriving at the top of the atmosphere, about thirty-five are turned back before they can heat the ground, twenty-seven from the tops of clouds, two from snow and ice covered surfaces and the remainder scattered by the atmosphere; this reflected share is the albedo…
Read the full explanation →The normal lapse rate of temperature in the troposphere is about:
- A.1 °C per 1,000 metres
- B.6.5 °C per 1,000 metres
- C.9.8 °C per 1,000 metres
- D.16 °C per 1,000 metres
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This is the normal lapse rate, the average fall of temperature with height in the troposphere, and it is the reason a hill station is cool while the plain at the same latitude is hot.
Read the full explanation →The earth is nearest to the sun, a position called perihelion, on about which date?
- A.3 January
- B.21 March
- C.21 June
- D.4 July
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The orbit of the earth is an ellipse, so the distance from the sun changes through the year; the earth is closest at perihelion about the third of January and farthest at aphelion about the fourth of July, which is option D and the usual distractor in this question.
Read the full explanation →The horizontal movement of air that transfers heat from one place to another is called:
- A.Conduction
- B.Convection
- C.Advection
- D.Radiation
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Advection is the sideways or horizontal transfer of heat by moving air, and in the middle latitudes most of the day to day variation in temperature comes from it; the hot loo that blows over north India in summer and the cold wave that follows a north-westerly wind in winter…
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