Assessing debris-covered glaciers using geospatial techniques in the Hindu Kush Region, Pakistan

This study employs geospatial techniques to assess the extent and characteristics of debris-covered glaciers in the Hindu Kush region of Pakistan. The variability in debris cover on glaciers globally poses a significant challenge to automated delineation and inventory processes. Satellite remote sensing data and geospatial analysis were used to map debris cover, delineate glacier boundaries, and evaluate temporal changes. Utilizing an ALOS PALSAR digital elevation model (DEM) with a spatial resolution of 12.5 m and thermal data. Morphometric parameters such as slope were computed using the PALSAR DEM. The Normalized Difference Snow Index (NDSI) was utilized to detect snow surfaces characterized by high reflectance. A technique involving imagery conversion of NDSI to raster, combined with a polygon overlay operation with slopes less than 15 degrees, facilitated the identification of debris-covered glaciers. The semi-automated mapping approach revealed a significant change in both snow and debris cover. In 2016, the snow cover area was 4134 km², and debris cover was 9899 km², whereas in 2020, the snow cover area increased to 5873 km², and debris cover decreased to 8128 km². The debris-covered glacier area reduced from 115 km² in 2016 to 50 km² in 2020. The results highlight the significance of debris cover in influencing glacier dynamics and potential meltwater contributions. While the semi-automated approach provided reliable delineation of debris-covered glaciers, the absence of direct field validation remains a limitation, underscoring the importance of future ground-truthing efforts to further strengthen the accuracy of remote sensing analyses.