How Well do Global Snow Products Characterize Snow Storage in High Mountain Asia?

Abstract

Accurate characterization of peak snow water storage in High Mountain Asia (HMA) is essential for assessing the water supply to over 1 billion downstream residents. Currently, such characterization still relies on modeling due to measurement scarcity. Here, eight global snow products were examined over HMA using a newly developed High Mountain Asia Snow Reanalysis (HMASR) data set as a reference. The focus of intercomparison was on peak annual snow storage, the first-order determinant of warm-season water availability in snow-dominated basins. Across eight products the climatological peak storage over HMA was found to be 161 ± 102 km3 with an average 33% underestimation relative to HMASR. The inter-product variability in cumulative snowfall (335 ± 148 km3) explains the majority (>80%) of peak snow storage uncertainty, while significant accumulation-season snowfall loss to ablation (51% ± 9%) also reveals the critical role of ablation processes on peak snow storage.