Why does tropical cyclone originate over the seas? In which part of the tropical cyclone do torrential rains and high-velocity winds blow and why?
The tropical cyclones originate in tropical seas. The conditions for the formation of the tropical cyclones are :
1. Large sea surface with the higher temperature, more than 27°C.
2. Small variation in the vertical wind speed.
3. A pre-existing weak low pressure area.
4. Upper divergence above the sea level system.
Over the Indian Ocean-especially in Bay of Bengal 50% cyclones are formed from a preexisting shallow low pressure area.
The eye of a cyclone is a region of tropical cyclone where a torrential rain occurs and the high velocity is there. The winds reach maximum velocity in this region as high as 250 km/hour. Around the eye is the eye wall where there is a strong spiralling ascent of air to greater heights in the troposphere.
Intensive Rainfall occurs to the left of the Cyclone. Maximum rainfall occurs close to the centre of the storm. Secondary, maximum of rainfall occurs 2º away from Primary maximum to the right of the storm centre. Slow moving/big size cyclones give more rainfall, whereas, fast moving/small size ones give less rainfall. More than 90% of rainfall is limited within 200 Km radius of the storm.
