Space-based assessment of glacier fluctuations in the Wakhan Pamir, Afghanistan

Abstract

Alpine glaciers directly and indirectly respond to climate and play a significant role in mountain geodynamics. Many glaciers around the world have been found to be retreating and downwasting, although these patterns are highly variable due to variations in local topography, regional climate and ice-flow dynamics. Unfortunately, limited information is available on glacier fluctuations in the Wakhan Pamir of Afghanistan, and no data exist from there in the World Glacier Monitoring Services (WGMS) database. Our general circulation model (GCM) climate simulations represent a double carbon-dioxide-loading scenario, and results suggest that glaciers in this region should be downwasting and retreating. Therefore, as part of the Global Land Ice Measurements from Space (GLIMS) project, we evaluated ASTER and Landsat MSS data to assess glacier fluctuations from 1976–2003, in the Wakhan Corridor of Afghanistan. We sampled 30 alpine valley, compound alpine valley or cirque-type glaciers of varying size and orientation. Results indicate that 28 glacier-terminus positions have retreated, and the largest average retreat rate was 36 m year − 1. Satellite image analysis reveals non-vegetated glacier forefields formed prior to 1976, as well as geomorphological evidence for apparent glacier-surface downwasting after 1976. Climatic conditions and glacier retreat have resulted in disconnection of tributary glaciers to their main trunk, the formation of high-altitude lakes, and an increased frequency and size of proglacial lakes. Collectively, these results suggest increased hazard potential in some basins and a negative regional mass balance.