Remote sensing of snow cover dynamics and climate implications in the Indus, Ganga, and Brahmaputra river basins

In the context of the Himalayan region, where glaciers and snow cover area (SCA) critically influence river runoff, monitoring SCA on a spatio-temporal basis is essential for the effective utilization of water resources. This study delves into the complex dynamics of snow cover within the Indus, Ganga, and Brahmaputra basins in the Hindu-Kush Himalayan region (HKH), leveraging the high temporal resolution of the Moderate Resolution Imaging Spectroradiometer (MODIS). The MODIS data, with its reduced cloud cover, offers an enhanced observation capability for these high-elevation regions. Our research focuses on evaluating the annual and seasonal variations in SCA across these basins from 2003 to 2021 and correlates these variations with critical climatic variables such as temperature and precipitation, using data from the fifth-generation European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis of the global climate (ERA5). The study presents a comprehensive assessment of SCA, highlighting significant findings that include a range of mean annual SCA from 22.31 to 42.14%, with notable seasonal fluctuations. The data analysis reveals a clear correlation between SCA variability and climatic parameters, particularly temperature, indicating a high sensitivity of snow cover to temperature changes. Notably, the most significant temperature increases and their impacts on SCA were observed in the Ganga and Brahmaputra basins. Furthermore, the study examines how topographical attributes such as elevation, slope, and aspect contribute to the distribution of SCA, revealing the critical role these factors play in determining the varying elevations of the snow line across each basin. These findings underscore the profound influence of climate change on snow cover dynamics in this region. The study's insights into the spatial and temporal variability of SCA, coupled with the observed climatic trends, emphasize the urgent need for adaptive water resource management strategies in these crucial river basins.