Monitoring snow cover in the Himalayan–Karakoram basins using AWiFS data: significant outcomes

Snow cover, the second largest component of the Earth’s cryosphere, controls the hydrology of basins, mass balance of glaciers and climate at the local, regional and global scale. Therefore, it is regularly observed through the Earth Observation (EO) dataset at fine, medium and coarse resolution to understand the impact of its variability in land–atmospheric inter­actions. The present study analyses of the variability of snow cover area within the Himalayan–Karakoram (H–K) region based on snow products generated by the NDSI approach using data from AWiFS sensor of Resourcesat satellites at an interval of five and ten days. The study covers 33 sub-basins of the Indus, Ganga and Brahmaputra basins in the H–K region. For analysis and presentation, results of the Indus basin have been further divided as Indus–North, Indus–South, Chenab and Satluj basins due to the large basin area. A high spatial and temporal vari­ability in the seasonal snow area was observed in the entire H–K region based on the sub-basin-wise 35,910 snow cover products generated between 2004 and 2019. A higher percentage of snow area in the Karakoram region than in the other sub-basins was observed throughout the years. Though interannual trends of snow cover area remained more or less stable in all the basins, a decreasing trend was observed in October in a few basins and an increase in snow area in the Indus–North region during December and January.