IMD planning early heatwave alerts
NEW DELHI: To facilitate better preparation for extreme heat stress possible in the coming years, the India Meteorological Department (IMD) will start providing an early warning lead and heatwave impact assessment, scientists of the weather monitoring agency and Indian Institute of Technology, Delhi (IIT-D), have said
In a comment piece in the journal ‘Nature India’ that was published Saturday, IMD director general M Mohapatra, the agency’s senior scientist R K Jenamani and IIT-D scientist S K Dash wrote that improving early warning lead time will help save more lives and will assist local administration to take better heat-action measures.
According to the piece, the assessment will be drawn up by factoring in relative humidity, night temperature and wind conditions for very hot days — when maximum temperatures of 45°C-49°C are reported — over northwest and central India.
“Heat waves are not new. There is evidence of large-scale heat waves in other parts of the world, including Europe and the United States. When the base temperature of the earth goes up, disturbances such as heat waves are most likely to occur. However, what is concerning is the evidence of increase in their frequency and intensity and numerical models suggesting possible future rise in temperature. Globally, the last seven years have been the warmest on record,” they wrote.
So far, the IMD has been issuing heatwave warnings 3-5 days in advance across the country.
“In India, the summer of 2022 unfolded in an unusual way as early as 11 March mostly over the plains of northwest, central
India, Gujarat and the western Himalayan region,” the comment notes, adding that the ‘major’ and ‘severe’ heatwaves came in six spells — March 11-23, March 27-April 12, April 17-20, 23 April 23- May 2, May 7-16 and May 19-2.
A comparison of heat waves of the past 13 years (2010-2022) shows record highs this year. March had the highest number (93) of meteorological sub-division days (MSD). MSD is the sum of the heatwave days in different meteorological sub-divisions of the country. April 2010 had the highest number (404) of MSDs of heat waves followed by 2022 at 209 MSDs.
March and April also surpassed earlier recorded values in the last 122 years.
“The efforts to improve forecast lead time and issue impactbased warning is already going on... We are saying that we should remain focused on early warning systems,” said co-author Dash.