Marine heat waves could have provided a favourable condition for the cyclone ‘Biparjoy’ to form over the Arabian Sea and become a very severe cyclone, say scientists of the Indian National Centre for Ocean Information Systems (INCOIS) under the Ministry of Earth Sciences (MoES).
A warmer ocean water column helps build moisture content in the air and thus provides the necessary energy source for cyclonic storms to form over the ocean. When the ocean remains warmer beyond a threshold from the normal condition for a prolonged period, these events are referred to as marine heatwaves. A marine heat wave was prevailing in the eastern Arabian Sea since early May. The sea surface temperature was more than 31° C (1° C warmer than normal), during the entire May and early June this year.
Senior scientist Abhisek Chatterjee and his students Gouri Anil, and Lakshmi R. Shenoy investigated the trends and genesis of heat waves and found these events are becoming prolonged and sometimes persistent for the entire pre-monsoon season in the recent decade. Their study showed similar heatwave conditions to be prevailing during the other recent severe cyclones such as ‘Tauktae’ and ‘Nisagra’, which hit the west coast of India and caused extensive damage to property and life.
