Atmospheric drivers of extreme precipitation events in the Indian sub-continent

Abstract

Extreme precipitation events in the Indian sub-continent have profound socio-economic and environmental impacts, particularly due to their role in triggering flash floods. These events are driven by a combination of atmospheric conditions, moisture sources and pathways, geomorphology, and hydrometeorology. However, while the hydrometeorological and geomorphological factors have been extensively studied, the role of atmospheric drivers and moisture pathways remains underexplored, creating a significant research gap. To address this gap, we analyzed the atmospheric processes and moisture sources contributing to widespread extreme hourly precipitation events across the Indian subcontinent during the period 1981–2020. Using a combination of reanalysis datasets, event detection algorithms, and moisture tracking methods, we identified the spatial and temporal distribution of these events. We find the Himalayas as a major hotspot, with most extreme events occurring during the Indian summer monsoon season. We find recycled moisture from land surfaces is the dominant source of moisture in the Himalayas, whereas moisture from the Arabian Sea and the Bay of Bengal primarily drives precipitation extremes in peninsular India. Our findings highlight the interconnected dynamics between the atmosphere, land, and ocean in driving extreme precipitation. The study underscores the importance of incorporating atmospheric drivers into disaster management frameworks and early warning systems to enhance preparedness and mitigate impacts effectively.