South-east Arabian Sea surrounding the Kerala coast suffers from enhanced deep atmospheric convection (vertical transfer of heat and moisture), resulting from unprecedented warming of the surface waters, points out the results of a study conducted by a group of scientists, including Prof. Brian Mapes of the School of Marine and Atmospheric Sciences of the University of Miami, U.S., and Dr. Abhilash S. of the Advanced Centre for Atmospheric Radar Research, Cochin University of Science and Technology.
Compared with the 1980s, the warming of the south-east Arabian Sea has exceeded by more than 1°C, surpassing the maximum sea surface temperature of 29°C in 1980s to greater than 30°C in 2020s. The warming in the Arabian Sea is about 1.5 times that of the rest of the world’s oceans. This has huge consequences in the form of increased frequency of deep (cumulonimbus) clouds even during the monsoon, leading to very heavy to extreme rainfall and cloud-burst type events. It is also alarming to learn that the warming in the south east Arabian Sea has paralleled the warming of the west-Pacific where the frequency of severe typhoons (cyclones) is on the higher end.
The warming has been responsible for the recent extremes and subsequent landslips in Kerala since 2018. Warming-induced enhanced thermodynamic instability of the atmosphere leads to the organisation of meso-scale convective clusters (huge cluster of thunderstorms and showers) which produce torrential rainfall.
The collaborators in the study include P. Vijaykumar, Baby Chakrapani, and K.Mohankumar from Cusat and O.P. Sreejith from the India Meteorological Department, Pune.
