Quantification of volume loss and snout retreat from 1980 to 2019 of baspa basin glaciers, western himalaya

Abstract Himalayan glaciers are under the enhanced retreating process and filed observations are scarce due to the harsh terrain and inclement weather in the upper Himalayan region. Under these conditions, the use of remote sensing and GIS technique is the best option for long term change detection in glacial features. Glacier length, area, and volume change analyses have been done using Landsat data series (MSS, TM, ETM+, and OLI/TIRS) from 1980 to 2019. Glaciers of Baspa basin were digitized in 1980 and 75 glaciers were reported whereas in 2019, number of glaciers were 84. During the period of 1980 to 2019, the number of glaciers were increased by 9 in the Baspa basin but the volume has been reduced. The increase in number has been due to the conversion of larger glaciers into a few smaller glaciers under the melting process. The results showed a general trend of loss in the areas and volume of the glaciers with varying magnitudes at different glaciers of the Baspa basin and in different periods. The overall retreat during 1980–2019 has been 22.40 ± 4.46% with the average loss in the area as 1.11 ± 0.01 km2 a-1 in the entire Baspa basin. The smallest rate of loss in the glacier area has been observed as 1.05 ± 0.01 km2 a-1 from 2001 to 2013. The Baspa basin possessed a glacial volume of 16.26 km3 in the year 1980 that got reduced to 12.98 km3 by the year 2019. The total loss in 39 years (1980–2019) has been calculated as 3.28 km3. The rate of loss in volume is highest in the period 2013 to 2019 which is 0.116 km3 a-1 and the minimum rate of loss in volume was observed from 1994 to 2001 i.e. 0.035 km3 a-1. The results on changes in the areal cover of glaciers as well as the volume are important for quantification of future water availability on the basis which controls the water supply in the river system. It is also of use in the planning of the hydropower sectors as well as the existing power plants in terms of the potential to generate electricity.