Districts in west, central Tamil Nadu face severe heat stress this summer
Explaining the difference between maximum temperature and heat stress, Raj Bhagat Palanichamy, a mapper and remote sensing expert, said heat stress occurs when a region is exposed to high temperature and humidity for a long duration
Heat Stress Map by Raj Bhagat Palanichamy (X/@rajbhagatt)
CHENNAI: It may feel oppressively hot in Chennai, but the capital city is not the worst affected in the State, show numbers. An analysis conducted by an expert revealed that the west-central region in Tamil Nadu is witnessing high heat stress, followed by south Tamil Nadu.
Explaining the difference between maximum temperature and heat stress, Raj Bhagat Palanichamy, a mapper and remote sensing expert, said heat stress occurs when a region is exposed to high temperature and humidity for a long duration. While the maximum temperature of any area is calculated at a particular time in the afternoon, the heat starts at 8am or 9 am and lasts until evening. Due to this, people would feel thermal discomfort, he said.
Heat stress factor is calculated using the number of hours exposed to different temperature and humidity levels as per the Universal Thermal Comfort Index (UTCI). In other words, heat stress is the total duration of thermal discomfort.
“I have calculated the heat stress factors based on temperature, humidity and duration records of May 1. As per the calculations, Erode, Salem, and Karur in west-central Tamil Nadu experience a high heat stress factor of up to 50. Madurai to Tirunelveli belt showed the second-highest heat stress factor, followed by the Vellore - Tiruttani region. The factor is based on how many hours the location is exposed to thermal stress,” he said.
Compared to these three regions, heat stress in the Chennai region is relatively low. Areas near the Western Ghats have a lower heat stress factor, with Ooty and Kodaikanal regions showing the least heat stress factor. Meanwhile, the Regional Meteorological Centre (RMC), Chennai, has warned that heatwave conditions will likely prevail over north interior Tamil Nadu.
Raj Bhagat worked with the State Planning Commission to prepare the ‘Heat Mitigation Plan’ for Tamil Nadu, which was recently handed over to the government. The plan is expected to be released after the Lok Sabha polls, and all government departments have recommended long-term measures to mitigate heat-related issues.