Intensity of cyclones may increase in future, shows IISc study
BENGALURU: Cyclones especially tropical cyclones, are large-scale phenomena with destructive impacts. A study by researchers from IISc shows that the mixing of oceans and cyclones is reducing the sea surface temperature and this is reducing evaporation, which will potentially increase the intensity of future cyclones.
In the study titled- Enhanced Ocean Mixing During the Passage of Tropical Cyclone- the researchers explained that temperatures are dropping by 0.5 degrees Celsius and the sea surface is getting colder.
The study was conducted by researchers from the Centre for Atmospheric and Oceanic Sciences (CAOS), IISc, which was also published in the AGU, Advancing Earth and Space Sciences. The study stated that in a warming climate, with the increasing intensity of powerful tropical cyclones, better knowledge of upper ocean turbulent mixing is necessary for improved forecasting.
“Powerful winds in cyclones cause vigorous mixing in the upper ocean, they cool the sea surface temperature and influence cyclone intensification. Using high-fidelity simulations and observations, the research team demonstrated the synergy between ocean convection and shear driven processes to change the upper ocean state. Due to temporally varying surface forces, the upper ocean mixing was also highly variable. The study provided new insights into the energetics of such an extreme event where both wind stress and surface cooling are present,” said the study paper.
Devang Falor, co-author of the study said, that during the one and half year study, the team studied the cyclones and their impacts at the Bay of Bengal from January 2023 to January 2024.
Falor, Prime Minister's Research Fellow (PMRF) and CAOS student said the mixing of oceans and cyclones changes the potential energy before and after the cyclones. Multiple simulation studies were done and change in energy was found to be happening at 0.00001 metres square per second cube. A drop in temperature was found to be by 0.5 degrees Celsius, which means that evaporation will be less and moisture in the atmosphere will also drop.
The study also stated that during tropical cyclones, rain bursts are sporadic in time, usually coinciding with surface cooling. Rainfall can also enhance the overall near-surface stratification by decreasing the of surface salinity and redistributing large surface momentum flux input from wind stress. For nighttime rain events, convection is suppressed near the surface due to strong salinity and overall stratification.