Assessment of precipitation and its extreme precipitation changes over the Himalayan Bhilangana River Basin, India

Abstract

Precipitation is a dominant driver of hydrological processes, and its reliable estimation is particularly important in the Himalayan region, where climate variability exerts strong control on water resources. This study evaluated changes in extreme precipitation over the Bhilangana River Basin, India, using multiple gridded datasets. Dataset performance was first assessed against station observation, with APHRODITE demonstrating the strongest agreement, followed by IMD, ERA5, and GPM. To refine accuracy, a hybrid statistical reconstruction was applied to generate a bias-corrected 0.10-degree precipitation dataset, which was subsequently employed to correct CMIP6 model outputs under SSP245 and SSP585 scenarios. A multi-model ensemble was then analysed for ETCCDI-recommended precipitation extremes across two future horizons: near future (2025–2054) and far future (2061–2090). Climate projections results indicate consistent declines in maximum one-day (Rx1day) and five-day (Rx5day) precipitation, reflecting a weakening of short-duration extremes. These reductions are accompanied by fewer consecutive dry days (CDD), while consecutive wet days (CWD) are projected to increase markedly. The most pronounced changes emerge in high-altitude regions, underscoring their elevated sensitivity to future precipitation shifts. These projected alterations highlight potential risks to glacier stability, flood regimes, and hydropower reliability, underscoring the urgency of developing climate-adaptive water management strategies in Himalayan basins. © The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2025.