The term cyclone is a Greek word meaning “coil of a snake”. Cyclones are centres of low pressure where, winds from the surrounding high pressure area converge towards the centre in a spiral form. Due to the rotation of the earth, the cyclonic winds in the northern hemisphere move in anti clock wise direction, where as they move in clockwise direction in the southern hemisphere. Cyclones can be classified into
Tropical cyclones, Temperate cyclones and Extra tropical cyclones . Tropical cyclones: Tropical cyclones develop in the Inter tropical convergence zone [ITCZ], They are formed due to the differential heating of land and sea. Tropical cyclones are known as ‘cyclones’ in Indian ocean, ‘typhoons’ in the western pacific ocean, ‘hurricanes’ in the Atlantic and eastern Pacific ocean, ‘baguios’ in Phillipines and ‘willy willy’ in Australia. Tropical cyclones often cause heavy .loss of life and property on the coasts and become weak after reaching the landmasses.
Temperate cyclones: Temperate cyclones are formed along a front where hot and cold air masses meet in mid-latitudes between 35° and 65°N and S. Temperate cyclones do not become weak like the tropical cyclones on reaching the land. Temperate cyclone commonly occurs over the North Atlantic Ocean, North West Europe, Mediterranean basin. Mediterranean basin’s temperate cyclones extend up to Russia and India in winter. In India it is as called western disturbances.
Extra tropical cyclones: Extra tropical cyclones occur in the latitudes between 30° and 60° in both the.hemispheres. They are also called as midlatitude cyclones. They collect energy from temperature differences which are found in higher latitudes. Extra tropical cyclones produce mild showers to heavy gales, thunderstorms, blizzards, and tornadoes.
