Test: Climate - 2 - UPSC MCQ

The troposphere is the lowest layer of Earth's atmosphere, extending up to 10 km at the poles and up to 18 km at the equator. The height of the troposphere is greatest at the equator due to the strong convection currents caused by the upward transportation of heat from the Earth's surface.

The ozone layer is primarily located in the lower portion of the stratosphere, between 15 and 35 km above the Earth's surface. The ozone layer plays a crucial role in protecting life on Earth by absorbing harmful ultraviolet (UV) radiation from the sun.

The primary causes of ozone layer depletion are human-made substances, such as chlorofluorocarbons (CFCs) and nitrous oxides. While volcanic eruptions can have significant short-term impacts on the atmosphere, they do not contribute to long-term ozone depletion.

The ionosphere, also known as the thermosphere, extends up to 400 km above the Earth's surface and contains electrically charged particles (ions). The ionosphere is the region where Earth's satellites are located, and is also responsible for reflecting radio waves, enabling long-distance radio transmissions.

Auroras are caused by the interaction between Earth's magnetic field and solar winds. When the magnetic field traps solar winds in the atmosphere, collisions between solar wind particles and atmospheric charged molecules (ions) result in the formation of auroras. There are two types of auroras: Aurora Borealis (Northern Lights) in the northern hemisphere and Aurora Australis (Southern Lights) in the southern hemisphere.

Temperature is influenced by various factors such as latitude, altitude, continentality, ocean currents and winds, slope, shelter and aspect, natural vegetation, and soil. However, population density does not directly influence temperature.

Temperature decreases with increasing altitude because the atmosphere is mainly heated by conduction from the Earth's surface. Thus, places near the Earth's surface are warmer than those higher up.

Due to the Earth's inclination, direct and oblique sunrays fall differently on different latitudes, causing temperature to reduce from the equator to the poles.

Ocean currents and winds affect temperature by transporting their heat or coldness into adjacent regions. For example, the westerlies that come to Britain and Norway tend to be cool winds in summer and warm winds in winter.

There is a definite difference in temperature between forested regions and open ground due to natural vegetation. Thick Amazon forests, for example, cut off much of the incoming insolation, keeping the land surface of the jungle cool and a few degrees lower than open spaces in corresponding latitudes.

Rainfall is the most common form of precipitation, occurring as the result of the condensation of atmospheric water vapor and its subsequent falling to the Earth's surface in the form of water droplets.

Convectional rainfall is common in Equatorial and Tropical regions in summers. It occurs when air on being heated becomes light and rises up as convectional currents. As it rises, it loses heat, and consequently, condensation takes place with the formation of cumulus clouds.

Cyclonic or frontal rainfall occurs along the fronts of cyclones, such as cold fronts and warm fronts. At the warm front, the warm lighter wind rises gently over the heavier cold air, which being heavy stays close to the ground. As the warm air rises, it cools, and the moisture present in it condenses to form altostratus clouds, resulting in steady rainfall for a few hours to a few days.

Rain shadow areas are formed in orographic or relief rainfall. When a warm and moist air current is obstructed by a mountain range, it is forced to ascend along its slopes. As the air ascends, it gets cooled, and when its temperature falls below the dew point, it causes rainfall on the windward slope of the mountain range. However, when these winds cross the mountain range and descend along its leeward side, they get warm and dry, causing only little rain (rain shadow areas).

Snowfall occurs when condensation takes place below the freezing point, and water vapour directly converts into a solid state in the form of fine snowflakes. Sleet, on the other hand, is formed when frozen raindrops or refrozen melted snow water fall from the sky. Sleet occurs when a layer of temperature above the freezing point overlies a sub freezing layer near the ground, resulting in precipitation in the form of sleet.