Climatology: UPSC Previous Year Questions (Geography)

Explanation

In the troposphere (near earth surface), temperature usually decreases as altitude rises. This is called the lapse rate. On average, the temperature drops by 1°C for every 165 meters of height. This equals about 6.5°C for every kilometer.

Statement 1 is correct: The Earth’s surface absorbs solar radiation and then re-radiates it as heat. The air in contact with the surface warms up and transfers heat to the layers above through conduction, convection, and radiation. Since the primary heat source is the Earth’s surface, higher altitudes receive less heat, leading to a drop in temperature.

Statement 2 is incorrect: Moisture content (water vapor) which accounts for around 1% of air varies greatly in the troposphere, decreases significantly with altitude, as most water vapor is found near the Earth’s surface. The upper atmosphere is drier, not more moist.

Statement 3 is correct: As altitude increases, air pressure and density decrease. Less dense air holds less heat, contributing to a decrease in temperature with height.

Explanation

The Tropical Savannah climate is characterized by a definite dry and wet season. This climate type is found in regions like parts of Africa, South America, and Australia. The distinguishing feature is the seasonal variation between a wet season (characterized by heavy rainfall) and a dry season (with very little or no rainfall).