Remote-sensing assessment of glacier fluctuations in the Hindu Raj, Pakistan

Space-based assessments of glaciers across the Himalayas indicate that there is a spatial variation in glacier fluctuations due to variations in local topography, regional climate, and ice-flow dynamics. Unfortunately, limited information is available on glacier fluctuations in northern Pakistan. In this work, we quantify the glacier terminus variations in the Hindu Raj region of Pakistan, where we used Landsat and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) time-series data for 1972, 1989, 1999, and 2007. Eighty-five mountain glaciers of various sizes, orientations, and altitudes were sampled. Our results show that most of the glaciers (70.6%) retreated over the last four decades, although some glaciers advanced (17.6%) or exhibited no detectable change in terminus position (11.8%). Larger glaciers with lower terminus altitudes exhibited greater retreat distances than smaller high-altitude glaciers. Long-term climate data analysis reveals that the recession of glaciers appears to be associated with the rising of summer temperatures in the Hindu Raj. Our results support a spatial trend of an increase in shrinking glaciers towards the western portion of northern Pakistan, with a greater frequency of advancing glaciers towards the east.