Shifting of the Zone of Occurrence of Extreme Weather Event—Heat Waves

Abstract

In this study, an attempt has been made to examine whether there has been any significant shift in the region of occurrence of extreme weather events associated with high temperature in the past decades during the months of March to June Following the India Meteorological Department (IMD) guidelines, we have identified heatwave locations all over India for the period 1991–2020 (3 decades) using the MAUSAM report and the period 1961–2020 (6 decades) using IMD gridded datasets at 1° × 1° resolution. In the first part, an analysis of extreme weather events caused by heatwaves (HW) and severe heatwaves (SHW) has been made. In each decade, a broad region of recurrence associated with HW/SHW has been identified. This process is repeated for a decadal-wise study. We observed a spatial–temporal shift in the occurrence of HW/SHW events, with a significantly increasing and decreasing trend in Indian states with HW/SHW-prone regions. The west coastal region has seen an increase in HW locations starting with the Konkan Coast up to Kerala. Also, the North-eastern states are facing HW/SHW in the third decade, which is a contradiction to otherwise cooler conditions. In the third decade, SHW locations appear as marked from northwest to southeast India around the central region, as if following a linear structure. The occurrence of HW/SHW in hilly states like Meghalaya, Assam, Himachal Pradesh, and Uttarakhand is an unprecedented and disastrous condition that can be a dangerous trend for the future. This observational evidence provides valuable insights into the impact of climate change on extreme heat events and helps inform mitigation and adaptation strategies.