Differential response of glaciers with varying debris cover extent: evidence from changing glacier parameters

Supraglacial debris (SGD) cover on mountain glaciers is known to greatly influence various glacier processes and alter their response to climate change. In this study, vital glacier parameters of five glaciers with varying debris coverage (about 7-26%), located in Zanskar basin, Ladakh Himalaya, were monitored using Landsat imagery (from 1977 to 2013) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) global digital elevation model (GDEM). Results reveal how varying amounts of SGD induce categorically distinct responses on glaciers, sharing same geographical settings. The clean glaciers (CG) in the area were found to have higher retreat rates (about 8-19 m year(-1)), comparable areal shrinkage (about 13-15%), higher accumulation area ratios (AARs) (>0.5), rapid increase in SGD (about 1.6-3.0-fold), and association with increasing numbers of peri-and proglacial lakes (2-8 per glacier). The debris-covered glaciers (DCG) showed minimal frontal changes (about 2-5 m year(-1)), higher areal shrinkage (about 14-21%), low AARs (<0.5), slow SGD changes (about <= 1.2-fold), and association with increasing numbers of peri-and supraglacial lakes (SGLs) (2-39 per glacier). Moreover, while changes in SGD had a strong negative correlation with changes in glacier area, retreat rates, and AAR, they were positively related with increase in area of SGLs.