What are the conditions for tropical cyclone formation? Why there is variation in frequency and intensity of cyclones in the Bay of Bengal and Arabian Sea? Discuss.

The tropical cyclone is a system of low pressure occurring in tropical latitudes characterized by very strong winds.
Favorable Conditions for formation of tropical cyclone

• Sea surface temperature should be generally in range of 26-28 degree C. Also the warm oceanic water should exist over a sufficient depth (i.e., 200 feet).
• Coriolis force, this is the reason why tropical cyclone don’t form near equator as the Coriolis force vanishes at equator.
• There should be Small variations in the vertical wind speed apart from that there should be upper divergence above sea surface.
• Potentially Unstable Atmosphere in order to sustain convection for an extended period of time

Variation in the frequency and intensity
Though cyclones originate in both the Bay of Bengal and the Arabian Sea side however the frequency is quite high in case of Bay of Bengal side especially of the stronger cyclones.
The reason is the relative colder water of the Arabian Sea is not a favorable condition for the formation and intensification of cyclones. Apart from that the Bay of Bengal side receives cyclones not only from Bay of Bengal and nearby areas but also from the Pacific Ocean, where the frequency of such cyclones is quite significant. Cyclones become weak once they encounter a big landmass, so cyclone from Bay of Bengal side do not travel to the Arabian Sea side. On the other hand the Arabian Sea side receives only those cyclones which originate locally or the cyclones which travel from the Indian Ocean near Sri Lanka.