Climatology — UPSC Prelims Geography previous year questions

Statement 1 is correct. The Andaman and Nicobar Islands have a hot, humid tropical coastal climate.
Statement 2 is correct. The islands get rain from the south-west monsoon, and also from the north-east monsoon in the later months.
Statement 3 is wrong. Most rain falls from May to December. December to May is the drier period.
So 1 and 2.
Remember: the islands have equatorial-type rain and no real winter.

Source: NCERT Class XI India: Physical Environment (Ch. 4 Climate)

Statement I is correct. Subtropical and temperate regions have more dust in the air than equatorial and polar regions.
Statement II is incorrect. These regions have more dry winds, not fewer. Dry winds lift dust from deserts and dry land.
So Statement I is right and Statement II is wrong. Option (c) fits.
Options (a) and (b) fail because they accept Statement II. Option (d) fails because Statement I is correct.
Remember: Dust particles act as nuclei on which water vapour condenses.

Source: NCERT Class XI Fundamentals of Physical Geography, Ch. 8 (Composition and Structure of Atmosphere)

Statement I is correct. In January, isotherms in the Northern Hemisphere bend equatorward over the landmasses and poleward over the oceans.
Statement II is correct. In winter, oceans lose heat slowly. The air over them stays warmer than air over land.
Statement II explains Statement I. Warm ocean air pushes isotherms poleward. Cold land air pulls them equatorward.
So option (a) is right. Option (b) fails because the reason does explain the pattern.
Remember: Water has a high specific heat, so oceans heat and cool slowly.

Source: NCERT Class XI Fundamentals of Physical Geography, Ch. 9 (Solar Radiation, Heat Balance and Temperature)

All three statements are correct.
Statement I: Without the atmosphere, Earth's average temperature would fall far below the freezing point.
Statement II: The atmosphere absorbs and traps heat. This keeps Earth's average temperature near 15 degrees Celsius.
Statement III: Gases like carbon dioxide are very good at absorbing and trapping outgoing radiation.
So I, II and III are correct.
Remember: The natural greenhouse effect keeps Earth habitable. Extra greenhouse gases strengthen it.

Source: NCERT Class XI Fundamentals of Physical Geography, Ch. 9 (Heat Budget and Greenhouse Effect)

Statement-I is incorrect. Short-wave sunlight passes through air with little absorption. It warms the ground first. The warm ground then gives out long-wave terrestrial radiation, and this heats the air more.
Statement-II is correct. Greenhouse gases such as carbon dioxide absorb long-wave radiation well. They hold this heat in the lower air.
Remember: the atmosphere is heated from below, not from above.

Source: NCERT Class XI Fundamentals of Physical Geography, Solar Radiation, Heat Balance and Temperature

Statement-I is correct. The troposphere is about 18 km thick at the equator. It is only about 8 km thick at the poles.
Statement-II is correct. Strong heating at the equator makes air rise in convectional currents. These currents carry heat to great heights.
Statement-II explains Statement-I. The deep convection is the reason the layer is thicker there.
Remember: the tropopause is higher and colder over the equator than over the poles.

Source: NCERT Class XI Fundamentals of Physical Geography, Composition and Structure of the Atmosphere

Statement 1 is correct. In January the northern oceans are warmer than the land at the same latitude. So isotherms bend north over the ocean and south over the continent.
Statement 2 is incorrect. The Gulf Stream and North Atlantic Drift are warm currents, not cold ones. They make the North Atlantic warmer, and this bends the isotherms to the north.
Remember: isotherms are lines joining places with equal temperature.

Source: NCERT Class XI Fundamentals of Physical Geography, Solar Radiation, Heat Balance and Temperature

Statement 1 is correct. Water vapour comes from evaporation near the surface. So it is most plentiful in the lower air and thins out with height.
Statement 2 is incorrect. Water vapour is greatest in the warm, humid tropics near the equator. It is least near the cold poles. It is certainly not absent at the equator.
Remember: warm air can hold more water vapour than cold air.

Source: NCERT Class XI Fundamentals of Physical Geography, Composition and Structure of the Atmosphere

This is the Marine West Coast climate. It lies on the western side of continents at 40°–60° latitude. Westerly winds bring moist air from the ocean all year. The ocean keeps the temperature range small.
Equatorial climate has much heavier rain, above 250 cm. China type (humid subtropical) climate has a clear summer rain peak and a larger temperature range.
Remember: Britain and north-west Europe have this climate.

Source: NCERT Class XI Fundamentals of Physical Geography (World Climate and Climate Change: Koppen scheme)

Statement 1 is correct. The deflecting force is proportional to the speed of the wind. A faster wind is deflected more.
Statement 2 is correct. The force depends on the sine of the latitude. It is zero at the equator and greatest at the poles.
So both statements are correct.
Remember: Coriolis force deflects winds to the right in the northern hemisphere and to the left in the southern.

Source: NCERT Class XI Fundamentals of Physical Geography, Atmospheric Circulation and Weather Systems

Statement 1 is incorrect. The contrast is greater in winter. Land cools far below the sea in winter, while in summer both warm up and the gap narrows.
Statement 2 is correct. Water has a higher specific heat than land. It heats and cools more slowly.
It follows that Statement 1 is false while Statement 2 is true.

Source: NCERT Class XI, Fundamentals of Physical Geography, Ch. 9 (Solar Radiation, Heat Balance and Temperature)

Statement 1 is incorrect. High clouds such as cirrus are thin. They let most sunlight pass. They trap outgoing infrared heat. So they mainly warm the surface.
Statement 2 is incorrect. Low clouds such as stratus are thick. They reflect much sunlight back to space. So they mainly cool the surface.
The two statements have swapped the roles of high and low clouds.
Remember: Infrared radiation is the heat energy given out by the Earth's surface.

Source: NASA Earth Observatory (Clouds and Radiation)

Statement 1 is incorrect. Jet streams occur in both hemispheres.
Statement 2 is correct. Only tropical cyclones develop a clear eye. Mid-latitude cyclones do not.
Statement 3 is incorrect. The air in the eye is warmer than the surroundings, not cooler.
So only statement 2 is correct.
Remember: The eye of a tropical cyclone is calm, clear and warm.

Source: NCERT Class XI, Fundamentals of Physical Geography, Ch. 9 (Atmospheric Circulation) and Ch. 10

Statement 1 is correct. The monsoon arrives in Kerala in early June and reaches the north-west by early July. It withdraws earlier from the north. So the rainy season is longer in the south.
Statement 2 is correct. Moisture-bearing winds lose water as they move inland. Rainfall falls from West Bengal and Bihar in the east to Punjab and Rajasthan in the west.
Remember: Kolkata gets about 160 cm of rain, Delhi about 70 cm.

Source: NCERT Class XI, India: Physical Environment, Ch. 4

The lower stratosphere has no clouds or water vapour, so there is little weather (statement 1).
It is a stable layer where temperature rises or stays constant with height. So there are few vertical winds (statement 2).
These calm and clear conditions let jets fly smoothly.
Both statements are correct.
Remember: Weather phenomena happen in the troposphere. The stratosphere is stable.

Source: NCERT Class XI, Fundamentals of Physical Geography, Ch. 8 (Structure of the Atmosphere)

Match each local wind with its region.
Foehn is a warm dry wind of the Alps (4).
Simoom is a hot dry desert wind of Arabia and Kurdistan area (2).
Santa Ana is a hot dry wind of southern California (3).
Zonda is a warm dry wind east of the Andes in Argentina (1).
So the order is 4, 2, 3, 1.
Remember: Foehn-Alps, Zonda-Argentina, Santa Ana-California.

Source: Certificate Physical Geography (G. C. Leong), local winds; NCERT Class XI, Ch. 9

A: Chennai is nearer the equator than Kolkata. Its lower latitude gives more heat, so A matches 5.
B: Temperature falls with height, so snow falls in the high Himalayas. B matches 2.
C: Monsoon winds lose moisture as they move inland, so rainfall falls with distance from sea. C matches 4.
D: Western disturbances bring winter rain to the north-west plains. D matches 3.
So the code is 5 2 4 3.

Source: NCERT Class XI, India: Physical Environment, Ch. 4

A. Cirrus is a high, wispy cloud made entirely of ice particles. It matches 4.
B. Cumulus is a puffy cloud seen in fair weather. It matches 3.
C. Nimbostratus is a thick, dark rain cloud, so it is grouped with storm clouds. It matches 1.
D. Stratus is a low, layered cloud like a high fog. It matches 2.
So the code is 4 3 1 2.
Remember: 'Cirro' means high clouds; 'nimbo' means rain-bearing.

Source: NCERT Class XI, Fundamentals of Physical Geography, Ch. 9

Tropical cyclones have different local names.
In the Indian Ocean they are called cyclones (A-3).
In the Atlantic Ocean they are called hurricanes (B-4).
In the South China Sea and western Pacific they are called typhoons (C-2).
In north-western Australia they are called willy-willies (D-1).
So the code is 3 4 2 1.
Remember: In the south-western Pacific they are also called cyclones.

Source: NCERT Class XI, Fundamentals of Physical Geography, Ch. 9 and 10

A. Mediterranean has warm to hot summers, mild winters and a moderate range. It matches 4.
B. Marine West Coast is moderated by the ocean. It matches 1.
C. Dry mid-latitude (steppe and desert) is inland and has a large range. It matches 3.
D. Moist continental has cold winters with three months below freezing. It matches 2.
So the code is 4 1 3 2.
Remember: Marine influence makes the range smaller; continentality makes it larger.

Source: NCERT Class XI, Fundamentals of Physical Geography; standard Koeppen-type climate descriptions