Test: Climate - 1 - UPSC MCQ

Anticyclones are large-scale circulations of winds around a central region of high atmospheric pressure. They herald fair weather, clearing skies, and calm air with high temperatures in summers and cold in winters.

Tropical cyclones are more destructive, originate only on sea and dissipate on reaching land, and move from east to west, while extratropical cyclones move from west to east, have a lower wind velocity, and can affect much larger areas, originating on land as well as sea.

The central low-pressure area of a tropical cyclone is known as the eye of the cyclone. It is calm with subsiding air, having the lowest pressure and highest temperature.

Cyclones move in an anticlockwise direction in the Northern Hemisphere and a clockwise direction in the Southern Hemisphere under the effect of westerlies due to the Coriolis effect.

Fohn winds are local hot and dry winds experienced on the leeward side of the mountains when descending air becomes compressed with increased pressure. They are experienced in the valleys of northern Alps, particularly in Switzerland in spring.

The reversal of Monsoon Winds in India is caused by the shifting of ITCZ, differential heating of continents and oceans, and the movement of the Sun. In summers, the Sun shines vertically over the Tropic of Cancer, resulting in high temperatures and low pressure in central Asia, while pressure is sufficiently high at the Bay of Bengal and Arabian Sea, inducing heavy rainfall in India and neighboring countries. In winters, the Sun shines vertically over the Tropic of Capricorn, causing the North-West part of India to grow colder than the Arabian Sea and Bay of Bengal, resulting in the reversal of monsoon in India.

On June 21, the Sun shines vertically over the Tropic of Cancer, and all pressure belts move 5-10 degrees northward from their original position.

Polar Winds give birth to cyclones when they come in contact with Westerlies. They bring frequent changes in weather conditions and cause heavy rainfall.

Westerlies are also known as brave winds or roaring forties, furious fifties, and shrieking sixties according to the varying degree of storminess in the latitudes in which they blow.

Trade winds do not typically cause considerable rainfall on the eastern margins of the continents. Instead, it is the prevailing westerlies that are responsible for the significant rainfall on the eastern margins of the continents. Trade winds are associated with relatively dry conditions, especially in areas affected by the subsidence of air from high-pressure systems.