Decadal Change in Supraglacial Debris Cover in Baspa Basin, Western Himalaya

Supraglacial debris cover (SDC) influences surface energy balance and glacier dynamics. However, very few studies have been carried out to understand its distribution and evolution. Previous glacier investigations carried out in Baspa basin, Western Himalaya, focus on retreat and mass balance. Therefore, the present study monitored change in SDC area from 1997 to 2014 using Landsat data. SDC area change was estimated within a ‘minimum snow-free glacier area’ using normalized difference snow index (NDSI) and band ratio of near infrared and shortwave infrared. Threshold values for NDSI and band ratio map were derived manually. The study was carried out for a ‘minimum snow-free glacier area’ of 60.5 ± 2.4 sq. km out of 174 ± 7 sq. km of total glaciated area. SDC area of 31.5 ± 1.4, 33.2 ± 1.2, 34.6 ± 1.9 and 36.3 ± 0.7 sq. km for 1997, 2000, 2011 and 2014 respectively, was estimated. Analyses show a linear increase in SDC area from 1997 to 2014 by 2.8 ± 0.4%. Naradu, a benchmark glacier in the basin, show one of the highest increase in SDC area (5.6 ± 0.4%). The findings from the present study are in line with other published results that suggest retreat, glacier fragmentation and mass loss, which could be due to climate change. The present study can be extended further using the SDC map and the results, in glacier hydrology and mass balance modelling to predict future loss.