Murtugudde Explains Cyclone Strength Through Sea Surface Temperature

ESSIC/AOSC Professor Raghu Murtugudde recently wrote a piece in Tech2 detailing how sea surface temperatures can determine the strength of a monsoon.

He wrote this in the eve of Cyclone Fani, a strong tropical cyclone that made landfall on the coast of Odisha, India on Friday, May 3.

Fani originated from the Bay of Bengal, a part of the Indian Ocean with sea surface temperatures above 28°C, the threshold for atmospheric deep convection.  These warm temperatures serve as an energy source for cyclones and can cause a tropical depression to grow into a tropical storm or a severe or very severe storm.  Warm weather can also lead to higher rates of evaporation that pump more moisture into the cyclone, leading to extreme amounts of rain when a storm hits land.  This phenomena is called cyclogensis.

This process is affected by climate change, as warming sea surface temperatures make perfect breeding grounds for tropical storms and cyclones.  This is particularly true for the Bay of Bengal, which got progressively warmer from 1 April, especially compared to the temperatures over the Arabian Sea.

Also affecting the formation of cyclones over the Bay of Bengal is the Findlater jet, south-westerly winds that carry moisture across the equator into India.

“When a cyclone forms over the Bay of Bengal, the moisture demand is so strong that the Findlater jet is dragged to become more eastward from its usual north-eastward tilt. All these factors complicate the cyclone development process as well as predictions of its track more than two to three days in advance,” writes Murtugudde.

Murtugudde is an Affiliate Professor for the Department of Geology currently serving as a Visiting Professor in Bombay, India.  He works primarily in climate studies, exploring the co-evolution of life and climate and what it means for sustainability.  He also writes a blog hosted on the ESSIC website.

To read the article, click here: “Understanding Cyclone Fani: How Sea Surface Temperature Determines the Strength of Cyclones”.