Estimating the volume of glaciers in the Himalayan–Karakoram region using different methods

摘要

Ice volume estimates are crucial for assessing water reserves stored inglaciers. Due to its large glacier coverage, such estimates are ofparticular interest for the Himalayan–Karakoram (HK) region. In this study,different existing methodologies are used to estimate the ice reserves:three area–volume relations, one slope-dependent volume estimation method,and two ice-thickness distribution models are applied to a recent, detailed,and complete glacier inventory of the HK region, spanning over the period2000–2010 and revealing an ice coverage of 40 775 km2. Anuncertainty and sensitivity assessment is performed to investigate theinfluence of the observed glacier area and important model parameters on theresulting total ice volume. Results of the two ice-thickness distributionmodels are validated with local ice-thickness measurements at six glaciers.The resulting ice volumes for the entire HK region range from 2955 to 4737 km3, depending on theapproach. This range is lower than most previous estimates. Results from theice thickness distribution models and the slope-dependent thicknessestimations agree well with measured local ice thicknesses. However, totalvolume estimates from area-related relations are larger than those fromother approaches. The study provides evidence on the significant effect ofthe selected method on results and underlines the importance of a carefuland critical evaluation.