UPSC Previous Year Questions (Prelims): Climatology | Geography for UPSC CSE PDF Download

Correct Answer is Option (c)
1. The Red Sea receives very little precipitation in any form:
The Red Sea is located in a very dry region, with a hot desert climate. It receives minimal rainfall due to the surrounding arid and semi-arid regions. The region is known for having very little precipitation, and it is classified as a desert climate, contributing to the low precipitation in the Red Sea.
2. No water enters the Red Sea from rivers:
Unlike many other seas, the Red Sea is not fed by any major river systems. It is a relatively isolated body of water, with limited freshwater input. The absence of significant river inflow means the Red Sea remains saline, and its water levels are maintained primarily by evaporation and inflow from the Indian Ocean via the Bab el-Mandeb strait.

Correct Answer is Option (d)
Statement I: The atmosphere is heated more by incoming solar radiation than by terrestrial radiation.
This statement is incorrect. While solar radiation does heat the Earth’s surface, the atmosphere itself is more significantly heated by terrestrial radiation (infrared radiation emitted by the Earth's surface) rather than directly by incoming solar radiation. The Earth's surface absorbs solar radiation and then re-radiates it as long-wave infrared radiation, which warms the atmosphere, especially through the greenhouse effect.
Statement II: Carbon dioxide and other greenhouse gases in the atmosphere are good absorbers of long wave radiation.
This statement is correct. Greenhouse gases like carbon dioxide, methane, and water vapor are efficient at absorbing and re-emitting long-wave infrared radiation. This process contributes to the greenhouse effect, which warms the Earth's atmosphere.

Correct Answer is Option (a) 
Statement I: Thickness of the troposphere at the equator is much greater as compared to the poles.
This statement is correct. The troposphere, the lowest layer of Earth's atmosphere, is thicker at the equator and thinner at the poles. The primary reason for this is the higher temperatures at the equator, which cause the air to expand, thus increasing the thickness of the troposphere.
Statement II: At the equator, heat is transported to great heights by strong convectional currents.
This statement is also correct. The intense heat at the equator causes the air to warm up, rise, and create strong convection currents. These convection currents help transport heat from the Earth's surface to higher altitudes.

Correct Answer is Option (a)
Statement 1: The isotherms deviate to the north over the ocean and to the south over the continent.
This statement is correct. Isotherms, which represent lines of equal temperature, typically deviate toward the north over oceans and toward the south over continents in January. This is because oceans have a higher heat capacity and retain warmth for longer, leading to higher temperatures in coastal areas, while land heats up and cools down more rapidly, causing lower temperatures on continents.
Statement 2: The presence of cold ocean currents, Gulf Stream, and North Atlantic Drift make the North Atlantic Ocean colder and the isotherms bend towards the north.
This statement is incorrect in its explanation. The Gulf Stream and North Atlantic Drift are warm ocean currents, and they actually warm the North Atlantic Ocean, not cool it. These warm currents cause the isotherms to bend northward over the North Atlantic, but their effect is to raise the temperatures in the region, not lower them.

Correct Answer is Option (a)
Statement-I: Rainfall is one of the reasons for weathering of rocks.
This statement is correct. Rainfall plays a significant role in the physical and chemical weathering of rocks. Water, including rainwater, can break down rocks through processes like erosion, dissolution, and chemical reactions.
Statement-II: Rain water contains carbon dioxide in solution.
This statement is correct. Rainwater absorbs carbon dioxide (CO₂) from the atmosphere, forming weak carbonic acid (H₂CO₃). This acidic solution can react with minerals in rocks, leading to chemical weathering. This is a form of chemical weathering known as carbonation.
Statement-III: Rain water contains atmospheric oxygen.
This statement is correct. Rainwater contains dissolved oxygen (O₂) from the atmosphere. This oxygen is involved in oxidation reactions, another form of chemical weathering, where minerals in rocks are oxidized (e.g., the rusting of iron-rich rocks).
Statement-II and Statement-III both explain Statement-I. The carbon dioxide in rainwater leads to chemical weathering through carbonation, and the oxygen in rainwater contributes to oxidation, both of which contribute to weathering.

Correct Answer is Option (a)
Statement 1: Correct. The amount of water vapor generally decreases with altitude, as higher altitudes have cooler temperatures and lower humidity.
Statement 2: Incorrect. The percentage of water vapor is maximum at the equator where the air is warmer and can hold more moisture, not at the poles where the cold air holds less moisture.

Correct Answer is Option (d)
The Marine West Coast climate is characterized by relatively moderate temperatures throughout the year (low annual and daily temperature ranges) and consistent precipitation throughout the year (ranging from 50 cm to 250 cm). This climate type is typically found on the west coasts of continents, especially in regions like the Pacific Northwest of the USA and parts of Europe.

Correct Answer is Option (c)
Statement 1: Correct. The Coriolis force is proportional to the velocity of the moving object (wind). Faster winds experience a stronger Coriolis effect.
Statement 2: Correct. The Coriolis force is strongest at the poles and weakest at the equator. It is zero at the equator because the rotational velocity is zero there.

Correct Answer is Option  (d)

• On June 21, the Tropic of Cancer experiences the summer solstice, where the northern hemisphere is tilted toward the Sun, leading to long daylight hours.
• The Arctic Circle experiences 24 hours of daylight during this time as it is in constant sunlight due to the tilt of the Earth.
• The Equator gets approximately 12 hours of sunlight throughout the year, but it does not have more than 12 hours on June 21
• Tropic of Capricorn experiences sunlight less than 12 hours on June 21.

Correct Answer is Option (b)
The Congo Basin is home to the largest tropical peatland, which plays a significant role in global carbon storage. The destruction of these peatlands can release large amounts of stored carbon into the atmosphere, contributing to climate change. The Amazon Basin is also significant for carbon storage, but the Congo Basin holds the largest tropical peatland.

Correct Answer is Option (d)

• Statement I is incorrect because the soil in tropical rainforests is typically poor in nutrients. The heavy rainfall in these areas washes away the nutrients, and the rapid decomposition of organic matter means that nutrients are quickly absorbed by plants rather than accumulating in the soil.
• Statement II is correct because the high temperature and moisture in tropical rainforests accelerate the decomposition of dead organic matter, which helps recycle nutrients in the ecosystem, though not necessarily leading to nutrient-rich soil.

Correct Answer is Option (a)

• Statement I is correct because the temperature contrast between continents and oceans is greater during summer than in winter. This is due to the fact that land heats up and cools down more quickly than water. In summer, land temperatures rise significantly, while ocean temperatures change more slowly.
• Statement II is correct because the specific heat of water is indeed higher than that of land. Water requires more energy to change its temperature compared to land. This difference in specific heat helps explain why land heats and cools more rapidly than water, contributing to the greater temperature contrast between continents and oceans during summer.

Correct Answer is option (C)

• Statement (a) is incorrect because the total amount of insolation at the equator is higher than at the poles, but not 10 times; it's typically about 2.5 times more.
• Statement (b) is incorrect because infrared rays constitute a smaller portion of the total insolation; most of the energy from the sun is in the visible light spectrum.
• Statement (c) is correct because infrared radiation is absorbed primarily by water vapour in the lower atmosphere, which plays a key role in the Earth's greenhouse effect.
• Statement (d) is incorrect because infrared waves are not part of the visible spectrum; they are beyond the visible spectrum, with longer wavelengths than visible light.

Correct Answer is option (C)

• Statement I is correct because India has significant uranium deposits but still depends heavily on coal for most of its electricity production. This is due to factors like the availability of coal, the infrastructure required for nuclear energy, and the high cost of nuclear power generation.
• Statement II is incorrect because uranium used for nuclear power generation typically needs to be enriched to a level of about 3-5%, not 60%. A 60% enrichment would be required for use in weapons-grade material, not for electricity production in reactors.

Correct answer is (d) 
Whether a given cloud will heat or cool the surface depends on several factors, including the cloud’s altitude, its size, and the make-up of the particles that form the cloud.

• Statement 1 is incorrect: Low, thick clouds primarily reflect solar radiation and cool the surface of the Earth.
• Statement 2 is incorrect: High, thin clouds primarily transmit incoming solar radiation; at the same time, they trap some of the outgoing infrared radiation emitted by the Earth and radiate it back downward, thereby warming the surface of the Earth.

Correct answer is (a) 
The term "Levant" generally refers to a geographical region along the eastern Mediterranean shores, which includes parts of modern-day countries like Syria, Lebanon, Israel, Palestine, Jordan, and sometimes parts of Turkey. It is historically significant as a crossroads of various ancient civilizations.

Correct answer is (b) 
Lake Faguibine, located in Mali, West Africa, has experienced severe drying and has turned into a desert-like landscape in recent years due to reduced rainfall and human-induced changes. It is a seasonal lake, but over the years, its water levels have decreased significantly, causing it to dry up intermittently.

Correct answer is (c) 
The Gandikota Canyon, often referred to as the "Grand Canyon of India," was formed by the Pennar River in the Kadapa district of Andhra Pradesh, South India. The river carved out this canyon, which is known for its stunning rock formations and beautiful landscape.

Correct answer is (b) 
Namcha Barwa is located in the Eastern Himalayas in Arunachal Pradesh, not in the Garhwal Himalaya. Therefore, Pair 1 is incorrectly matched.

• Nanda Devi is located in the Kumaon Himalaya in Uttarakhand, making Pair 2 correctly matched.
• Nokrek is located in Meghalaya, not in the Sikkim Himalaya, so Pair 3 is incorrect.

Hence, only Pair 2 is correctly matched.

Correct Answer is Option (c)

• Statement 1 is correct:Warmer water is transported westward in the ocean by the Northeast trade winds in the Northern hemisphere of the tropical zone (as the figure given below shows). So, in tropical zones, the western section of ocean is warmer than eastern sections due to trade winds.  
• Statement 2 is correct:Similarly, the Westerlies play an important role in carrying the warm, equatorial waters and winds to the western coasts of continents (that is eastern section of the Oceans in temperate zone). Thus, in temperate zones, westerlies make the eastern section of the ocean warmer than the western sections.  

Correct Answer is Option (c)

• Jet streams are high altitude westerly wind system blows at a height of 6 to 14 km, with very high speed up to 450 km/hr in the wavy form at both hemispheres.  So #1 is wrong. 
• The Centre of the cyclone is called an Eye. The eye is a Calm region with no rainfall and experiences the highest temperature and lowest pressure within the cyclonic system.  So  #3 is wrong. So, by elimination, the answer is (c).

Correct Answer is Option (b)

• OMT is measured up to a depth of 26 degrees C isotherm. During January–March, the mean 26 degrees C isotherm depth in the Southwestern Indian Ocean is 59 meters. So, #1 is wrong. 
• Sea surface temperature (SST) is routinely used for predicting whether the total amount of rainfall that India receives during the monsoon season will be less or more than the long-term mean. However, ocean means temperature (OMT) has a better ability to predict this, than SST. So, #2 is correct.

Correct Answer is Option (d)
As per the NASA webpage:

• Large amounts of methane are frozen in Arctic tundra soils and in marine sediments including gas hydrates. As Earth's climate warms, that methane is vulnerable to possible release into the atmosphere, where it can add to global warming. So 1 and 2 are correct. 
• In Methane Cycle, every molecule of methane that goes into the atmosphere remains there for 8 years until it is removed by oxidation into carbon dioxide (CO₂) and water (H₂O). So, 3 is also correct. This, answer (d): All three are correct.

Correct Answer is Option (a)

• On 21st June, the Northern Hemisphere is tilted towards the sun. The rays of the sun fall directly on the Tropic of Cancer. So, (c) and (d) are wrong. 
• Places beyond the Arctic Circle experience continuous daylight for about six months. So (a) is correct.

Correct Answer is Option (c)

NCERT Biology Class 12 page 127: “There was no atmosphere on early earth. Water vapor, methane, carbon dioxide, and ammonia released from molten mass covered the surface.” So #2 is wrong, CO₂ was present, we are left with (a) or (c). In both options the first statement is correct but experts were divided over the third statement because the early Early atmosphere of earth had no free oxygen, the (life) forms until then could at best be only “anaerobic”. So those living organisms did not have the capacity to alter the atmosphere, at least not in a significant manner. Accordingly, some ticked  ‘a’ while others ticked ‘c’. UPSC has kept ‘c’ as the official answer.

Correct Answer is Option (b)
The Westerlies are prevailing winds from the west toward the east in the middle latitudes between 30 and 60 degrees latitude. They originate from the high-pressure areas in the horse latitudes and tend towards the poles and steer extratropical cyclones in this general manner. The moist air masses that cause winter rains in the North-Western region of India are part of westerlies.

Correct Answer is Option (a)
The first statement is correct. One major factor affecting the distribution of the temperature of Earth is the distribution of Land and Oceans. Since there is more land in Northern Hemisphere and more waters in the Southern hemisphere and there is a big difference between the specific heat of land and water; the loss of heat from the continents is bigger than the oceans. The continents get heated faster and get cooled faster in comparison to the Oceans. This is the reason that the temperatures of the Oceans are moderate while that of continents is extreme. The moderating effect on the temperature of the land due to the proximity of the seas is called Maritime influence. The increasing effect on the temperature of the land in the interior of the continents is called Continental Influence.

Correct Answer is Option (b)

1. Rotation of the Earth
2. Air pressure and wind
3. Density of ocean water. 

Revolution has no impact on ocean currents.

Correct Answer is Option (c)
Jet flies in the lower stratosphere to avoid turbulence. There are no clouds and the air is dry with little water vapor. There are no vertical winds in the lower stratosphere.

Correct Answer is Option (a)
It is under the influence of cold ocean currents. So given the second statement is wrong.

Correct Answer is Option (a)
The speed of these winds is higher and more persistent in the southern hemisphere. The land mass in the southern hemisphere is lesser in comparison to the northern hemisphere. As these winds cross the landmass its velocity decreases. Thus the effect of westerlies is less over the northern hemisphere than in the southern hemisphere.

Correct Answer is Option (b)
Statement 1 is wrong, ionosphere contains charged particles due to which electromagnetic radio waves get reflected and communication becomes possible. Ozone is found mainly in the stratosphere and in traces in the troposphere. Its main function is the absorption of UV rays. While the ions give the ionosphere its name, it is the free electrons that affect the radio waves and radio communications. Also, Radio waves have the longest wave length in the EM spectrum.

Correct Answer is Option (c)
Rotation of the earth causes the wind to deflect towards the left in the Southern Hemisphere.

Correct Answer is Option (a)
Mediterranean climate has mild, rainy winter and hot, dry summers and Evergreen, Oak trees

Correct Answer is Option (a)
Albedo is the fraction of the incident sunlight that is reflected. When an object reflects most of the light that hits it and looks bright then it has a high albedo. The albedo of mercury is 0.1 and that of the earth is 0.30.

Correct Answer is Option (a)
A is true as the direction of the wind in the north ern hemisphere is clock wise and in the southern hemisphere, it is anti clock wise. The explanation is correct as this is mainly due to the Coriolis effect.

Correct Answer is Option (a)
The atmosphere of Venus is composed primarily of carbon dioxide and much denser and hotter than that of Earth. The atmosphere of Venus supports opaque clouds made of sulfuric  acid, making optical Earth-based and orbital observation of the surface impossible.

Correct Answer is Option (d)
The circulation of atmosphere and oceans is fundamentally caused by the fact that the amount of incoming solar radiation varies from a maximum at the equator to a minimum at the poles. More reflection and absorption of incoming radiation takes place in high latitude because of the greater thickness of atmosphere that must be penetrated. Thickness of the earth is maximum over the pole.

Correct Answer is Option (c)
A is true but R is false. Sub-polar low pressure is located between 60–65º latitude in both hemisphere. Low pressure is produced in this area, because the surface air spreads outward from this zone due to rotation of earth.

Correct Answer is Option (b)
Ocean currents are not slow most of the time and can be subsurface current also. So, statement '1' is wrong. But '2', '3' and '4' statements are correct.

Correct Answer is Option (d)
Benguela is a cold current flows from south to north along the west coast of Africa. Guinea current is a warm current flowing east of Guinea along the west coast of Africa.

Correct Answer is Option (c)
The correct sequence of different layers of atmosphere from the surface of earth is Troposphere, Stratosphere, Mesosphere and Ionosphere. Troposphere extends upto 8 km from earth surface, but at equator it is 16–18 km. Stratosphere extends above Troposphere 18–50 km. Mesosphere extends up to 80 km and above Mesosphere Ionosphere is present, which extends up to 400 km.