Question: Lower latitudes are vulnerable to tropical cyclones. Explain the factors that contribute towards formation of cyclones.
Answer: A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure centre, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain.
The tropical cyclones are called with different names based on the locations of their occurrence.
Formation of tropical cyclones
- High temperature
Cyclones are formed in region with high temperature preferably between 25-27 degree celcius. The high temperature causes a low pressure region to originate over sea water that is perfect for formation of rotating air mass.
- Trade winds
The trade winds in form of easterlies and westerlies are important for creating the required circulating air masses. These winds give the cyclones their characteristic circular rotating feature. Direction of rotation of winds depends on its location in northern or southern sphere.
- Coriolis force
Coriolis force occurs due to rotating nature of earth. It is highest at the poles and lowest at the equator. The winds at the outer wall of the cyclone bend due to coriolis force. Without this force, the cyclone does not obtain the required rotative characteristic.
Thus, tropical cyclones require certain geo-climatic conditions for occurrence and are mostly observed in South China sea, Caribbean sea, Northern Indian Ocean and Southern Indian Ocean.