Changes in the spatial variability of extreme precipitation characteristics across Peninsular India

Abstract Through a comprehensive analysis, this study portrays the changing spatial variability of extreme precipitation characteristics as a consequence of a gradually warming climate in peninsular India. In particular, it emphasizes the coastal areas that are under increased exposure to frequent extreme events in the recent past. Different extreme precipitation characteristics are considered, and the change points are identified based on their trend, mean and standard deviation. Changes in the spatiotemporal variability of extreme precipitation characteristics are identified through empirical orthogonal functions (EOFs). Our findings illustrate the occurrence of discernible changes almost all over the region with varying time points (1970 to 2011), and the extremes with higher thresholds exhibit more prominent changes. More importantly, a notable disparity in extreme indices expressing intensity is observed between the eastern and western coastal regions: change points for the eastern coastal areas (the Bay of Bengal side) predominantly emerged in the post-1980s, in contrast to the pre-1980s points across the western coastal (the Arabian Sea side) regions. Furthermore, after 2001, the spatial coverage of the western region notably expanded, as indicated by a significant increase in wet extremes, including those at the southernmost tip of India. Concurrently, extreme dry events significantly decreased across most of southern India during this period. On the other hand, the intensification of precipitation has become more prominent towards the Bay of Bengal side than towards the Arabian Sea side. This may be attributed to the increased cyclonic activity in the Bay of Bengal. Overall, the findings of this study will aid in understanding the evolving spatial pattern of extreme precipitation indices and will contribute to better management of extreme events and related hazards across peninsular India.