Decadal Estimates of Surface Mass Balance for Glaciers in Chandra Basin, Western Himalayas, India—A Geodetic Approach

Abstract

The Himalayas, which has the highest concentration of glaciers outside the poles, form a huge reservoir of fresh water. These glaciers are not only important because of the contribution they make to our water resources, but also because they are a great help in understanding the effects of climate change. However, monitoring even a few of these glaciers through field techniques is a tedious process due to the tough and unapproachable terrain of the Himalayas. In such situation, remote sensing techniques become a boon. In this article, one such widely used remote sensing-based technique called digital elevation model (DEM). Differencing or geodetic approach available for estimating glacier surface mass balance (SMB) is discussed. However, the accuracy of the estimated SMB using geodetic approach is highly dependent on the accuracy of the DEMs used, which ultimately decides whether this approach can be used for seasonal, annual or decadal studies. To get a better understanding of this approach, this article gives a brief overview of errors present in DEMs and how to correct it before estimating SMB by demonstrating it over 65 glaciers located in the Chandra basin, Lahaul--Spiti district of Himachal Pradesh, India. The obtained results indicate that the Chandra basin has lost 5.01{\thinspace}{\textpm}{\thinspace}2.48 Gt of ice mass during the course of 14 years (1999--2013), which gives a clear signal on the effect of climate change occurred over the study area and how climate change could cause imbalance in the health of glacier(s). Considering the advantages of this approach and recent developments in high-resolution DEM data acquisition as well as the need for such accurate mass balance estimates across Himalayas, it is therefore suggested that this modelling approach should be extended to other basins to get the current status of the health of the glaciers across Himalayas.