Understanding the spatial distribution and plausible genesis of supraglacial debris over the Himalaya-Karakoram region

ABSTRACT The majority of studies discuss the impact of supraglacial debris on glaciers’ health while the rationale behind the formation and regional distribution of supraglacial debris in the Himalayan-Karakoram (H-K) region is sparsely researched. The present study attempts to evaluate the role of meteorological, topographical, and geological parameters to understand the regional distribution and plausible genesis of supraglacial debris in the H-K area. Glacier-wise Fractional Debris Cover (FDC) for ~5000 glaciers have been estimated using LANDSAT-7 data (1999–2001) based on the Normalized Difference Snow Index. The aforementioned parameters, including FDC, are compiled into a comprehensive database and analysed. Moreover, “2-meter air temperature” from ERA-5 climatological data is used to estimate the number of Freeze–Thaw Cycles. Overall meteorological and topographical parameters show a significant correlation with the distribution of FDC across the H-K region, more prominently for glaciers having low FDC (<0.2). FDC distribution shows a strong dependency on glacier hypsometry with the highest FDC for “Very Bottom Heavy” glaciers and the lowest for “Very Top Heavy” glaciers. The glaciers with Limestone bearing lithology have maximum FDC and are sparsely distributed, but the glaciers with quartzite bearing lithology are widely distributed across the region and have lower FDC.