An integrated approach to quantify changes in NW Indian himalayan ice and snow in large spatial extent

Abstract

Monitoring spatio-temporal changes in glaciers and snow is important for estimating the impact of climate change in glaciated landscapes. The existing methods to map snow, ice, and debris-covered glaciers are complicated and have limitations. We introduce an integrated methodology to map the extent of total snow, isolated ice pockets together with the glaciers at the regional (megascopic) scale. In addition, we examined the sensitivity of the proposed methodology to different scales of mapping and datasets with different spatial resolutions (Landsat 8-30 m and Sentinel 2A-10 m). We implemented the approach in the five major river basins of Northwest India and developed an inventory for all the components of its glaciated area. All these data will help by providing inputs in hydrological models for assessing meltwater generated from the catchment. A change detection analysis in all these five river basins shows a maximum decrease in glacier and ice bodies by around 40% in the Ravi River basin to an overall 3% decrease in glacier and ice bodies in the Beas River basin over the past two and a half decades. The maximum loss in permanent snow cover is also in the Ravi River basin, whereas snow cover in the Yamuna River basin shows a slight increase. We also observed a rise in temperature, a recession of snowlines, and the emergence of glacial lakes in the region.