Heatwave mapping using satellite-derived LST in Western Madhya Pradesh, India

Abstract

Approximately 60% of India's population is exposed to extreme temperatures that exceed critical health risk thresholds for 10 to 20 days each year. However, the distribution of heat and the associated vulnerabilities vary significantly across the country’s physiographical regions, making it challenging to identify high-risk areas. Recognizing these hotspots and establishing a comprehensive framework to integrate risk management systems into decision-making processes is crucial. In particular, there is a need to focus on threshold detection methods to highlight the importance of further research in regions susceptible to heatwaves. This study utilized MODIS Land Surface Temperature (LST) data alongside daily mean gridded surface air temperature data from the India Meteorological Department (IMD) to analyze 33 heatwave events that occurred between 2009 and 2020 in western Madhya Pradesh, central India. The findings demonstrate that satellite-derived LST data can effectively identify regional heatwave patterns, with a strong correlation (correlation coefficient approximately 0.7) observed between heatwaves detected via air temperature anomalies and those estimated using LST departures. Furthermore, the study established optimal LST thresholds for heatwave detection: the 70^th percentile (52.5 °C) for standard heatwaves and the 90^th percentile (53.5 °C) for severe heatwaves. Additionally, the results indicate a noticeable trend of summer warming in northern and central India, leading to increased heatwaves' frequency, intensity, and duration over the past decade.