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Line of sight glacier velocity estimation of transboundary glaciers in Eastern Himalayas using high-resolution TerraSAR-X data.
* 1 , * 1 , 1 , 2
1  Sikkim Manipal University
2  Sikkim State Council of Science and Technology
Academic Editor: Deodato Tapete


Glacier velocity is one of the critical parameters for understanding the current health status of a glacier. According to the momentum law, mass is inversely proportional to velocity. Higher velocity may indicate lesser mass. Fifteen transboundary glaciers from the eastern Himalayas in the vicinity of India, Nepal, Bhutan, and China are chosen for the estimation of glacier velocity. These glaciers are Changshang, Rathong, South Lhonak, South Simvo, Talung, Tongshiong, Yalung, Zemu, Glacier 2, Glacier 3, Kaer, Ktr Gr 193, Middle Lhonak, North Lhonak, and Ktr Gr 171 (Lhonak Nepal) covering total area of 440.92 km2. A remote sensing and GIS-based approach is considered for the study. High-resolution Synthetic Aperture Radar data of TerraSAR-X was acquired from the German Aerospace Center (DLR) by European Space Agency for study area in the year 2020-2021. Satellite data are preprocessed using radiometric calibration and multi-look for speckle noise reduction. These datasets are co-registered using SRTM Digital Elevation Model. Offset Tracking is applied to estimate the glacier velocity. The maximum velocity in all glaciers ranged from 14.31-84.26ma-1. The average velocity ranged from 1.78-7.09ma-1. The glacier having highest average velocity is South Lhonak glacier. This glacier is melting rapidly in the last few decades. Near the snout of this glacier lies a glacial lake made up of a moraine dam. For quality assessment, latest field-based results of 2018 and observed results of 2021 were compared. It has been noticed that there is a variation of approximately 10%.

Keywords: Glacier velocity; Eastern Himalaya ; Transboundary Region; Offset Tracking