Response of the Thick and Thin Debris-Covered Glaciers between 1971 and 2019 in Ladakh Himalaya, India—A Case Study from Pensilungpa and Durung-Drung Glaciers

This paper aims to broadly understand the response of glaciers to thick and thin debris cover from one of the less explored regions (Zanskar) of the Himalaya. The present study is based on ground-based measurements (from 2015 to 2019), satellite data (since 1971), and available topographic maps (at a 1:50,000 scale). The study includes snout retreat, changes in equilibrium line altitude (ELA), surface elevation, and modeled mass balance of thick and thin debris-covered Pensilungpa (Suru River basin) and Durung-Drung (Doda River basin) glaciers in the western Indian Himalaya, Ladakh, for the past five decades. The Durung-Drung Glacier (DDG) receded ~−624 ± 547 m with an average rate of −12 ± 11 m a −1 between 1971 and 2019. The frontal part of the DDG is broad (~2 km wide), which shows wide discrepancies in its retreat. Compared to DDG, the small and narrow snout of the Pensilungpa Glacier (PG) retreated −270.5 ± 27.5 m (1971 to 2019), with an average rate of −5.6 ± 0.57 m a −1 . Similarly, the four years (2015–2019) of field observations suggest that the retreat rate of PG and DDG is −6.7 ± 3 and −18 ± 15 m a −1 , and the rate of modeled glacier mass loss is −0.29 ± 0.3 and −0.3 ± 0.3 m w.e. a −1 , respectively. Furthermore, the ELA of the DDG and PG between 1971 and 2019 increased by ~59 ± 38 and ~23 ± 19 m, respectively. The change in the longitudinal profile of the glaciers along the centerline between 2000 and 2017 shows the DDG and PG lost ~17 and 15 m surface ice thickness. The change in debris cover plays a critical role in the glacier surface lowering, shrinkage, retreat, and mass balance. Hence, we quantitatively evaluated the influence of the debris cover on summer ablation and terminus recession on two different characteristic glaciers (DDG and PG) with its potential effect on the mass balance process (area-volume loss).