Heatwaves Over the Indian Subcontinent: Mechanisms, Variability and Sources

Abstract

Heatwaves, an extreme temperature events, have gained copious attention. This study conducts a comprehensive analysis of heatwaves (HWs) over four decades from 1980 to 2021. Empirical Orthogonal Function (EOF) analysis is used to identify the dominant spatial pattern in maximum temperature (T<inf>max</inf>) variability across the Indian region. The analysis identifies four significant regions: Central Northeast (CNE), South Central (SC), Northwest (NW) and Southeast (SE) with distinct temperature pattern. Subsequently, the spatial and temporal variations in HWs, indicate an increase in frequency, severity, and duration over the past four decades. Temporal trend shows an increase in HW frequency and duration across most of the regions over a 42-year period. To comprehend the underlying mechanism of HW events, study investigates various meteorological parameters observed during HW days. Maximum temperature anomalies increase by 4–5 °C, accompanied by positive surface solar radiation (SSR) of 10–20 W/m2 along with lower mean sea level pressure (mslp), and a reduction in relative humidity (RH) of − 6% to -15%. Geopotential height at different pressure level highlight anticyclonic circulation pattern associated with temperature extremes. Additionally, backward trajectory analysis is used to delineate distinct source regions and atmospheric processes linked with HW events in different parts of India. A detailed analysis of spatial and temporal variation of HWs and their associated meteorological factors contribute in development of effective mitigation and adaptation strategies. © King Abdulaziz University and Springer Nature Switzerland AG 2025.