IMD to start issuing heat index for 1st time from today
Union earth sciences ministry secretary said the index will be issued to make such data more accessible to the public for precautionary measures
For the first time, India Meteorological Department (IMD) will on Friday start issuing heat index for different parts of the country, combining air temperature and relative humidity for the public to accordingly take related precautions.
The heat index is also known as the apparent temperature. It is the temperature humans feel when relative humidity combines with the air temperature.
The index will be based on a formulation of the American National Oceanic and Atmospheric Administration (NOAA).
IMD director general M Mohapatra said the formulation is not based on the physiological responses of the Indian population and they will hence have a disclaimer that the heat index has not been validated here. “But it is indicative for understanding the implications of heat on the general public.”
The heat index is based on academic R G Steadman’s table using relative humidity and dry bulb temperature to calculate the temperature a human body feels.
Union earth sciences ministry secretary said the index will be issued to make such data more accessible to the public for precautionary measures. “We also need to work with the Union health ministry on providing information on comfort factors,” said Ravichandran.
IMD said the heat index will be provided for the entire country daily in weather bulletins.
On Tuesday, IMD recommended a comprehensive response plan for heatwaves including cultural, institutional, technological, and ecosystem-based adaptation strategies as it released a report saying most parts of India will face an increase in the duration of heatwaves by 12-18 days by 2060.
The report said heatwaves have claimed more lives in India than other natural hazards with the exception of tropical cyclones.
A heatwave is declared when the maximum temperature is above 40 degrees Celsius and 4.5 degrees above normal. A severe heat wave is declared when the temperature is above 40 degrees Celsius and 6.5 degrees above normal. Heatwaves usually occur in the period from March to June in central and north-western India (heatwave zone) and in the coastal areas of Andhra Pradesh and Odisha.
On average more than two heatwave events occur in northern parts of the country and coastal Andhra Pradesh and Odisha. In some pockets, heatwave frequency even exceeds four in a season.
