Monitoring glacier surface velocity in Zanskar Valley, India: Insights from DInSAR-based 2D velocity estimation

Glacier surface velocity plays a crucial role in understanding glacier dynamics, climate change impacts, and water resource management. In this study, Differential Synthetic Aperture Radar Interferometry (DInSAR) and geoinformatics techniques were employed to estimate the two-dimensional (2D) surface velocity of glaciers in Zanskar Valley, Ladakh, India. The analysis is based on C-band Sentinel-1 radar data acquired in both ascending and descending orbits to decompose the motion into horizontal and vertical components. The selected glaciers—Pensilungpa, Drang Drung, Khulka, and Kungi—exhibit varying velocity patterns, influenced by topography, ice thickness, and crevasse distribution. The results indicate that the Drang Drung Glacier, the largest in the study area, has the highest surface velocity, reaching approximately - 0.24 ± 0.02 in the upper accumulation zone. Pensilungpa Glacier exhibits distinct velocity variations, with rates of 0.07 ± 0.005 m/day near the equilibrium line altitude (ELA) and lower velocities near the terminus. The vertical and horizontal velocity components provide insights into the dominant glacier flow mechanisms, including ice deformation, sliding, and mass influx from tributaries. The study highlights the effectiveness of DInSAR for estimating glacier motion in complex mountainous terrain. The findings contribute to improved glacier monitoring and future ice thickness assessments, particularly for slow-moving glaciers. The methodology can be extended to other Himalayan glaciers and further refined using multi-frequency SAR data for enhanced accuracy. This research underscores the potential of satellite-based techniques for assessing glacier dynamics and their response to climate change.