Quantification of glacier mass budgets in the Karakoram region of Upper Indus Basin during the early twenty-first century

Abstract

Water supply contributed by glacier and snow melt is of particular significance and play a key role for social stability in the Karakoram region of Upper Indus Basin (UIBKK). Based on the SRTM DEM, TerraSAR-X/TanDEM-X images and ZY3-02 stereo images, the spatiotemporal pattern of glacier mass budgets in the UIBKK have been estimated for the early 21st century (2000–2019) period in this study. A comparison of the total area in 2000 with that in 2019 shows that glacier area remained stable in the early 21st century, with a slight expansion of 56.3 km2 (0.4%). Glaciers in the UIBKK experienced a balanced or slight negative mass budget of −0.08 ± 0.07 m w.e. a−1 in the early 21st century. The spatial variability of mass budget in the UIBKK showed that glacier mass budgets shifted from negative to positive from West to East, respectively, along longitude. Glacier mass loss decelerated from −0.12 ± 0.16 m w.e. a−1 in 2000–2013 to −0.03 ± 0.21 m w.e. a−1 in 2013–2019. No significant differences were observed in thinning rates on debris-covered glaciers (≥19% area covered by debris) and clean-ice glaciers (<19% area covered by debris) in the early 21st century (−0.06 m a−1 vs −0.04 m a−1). The overall homogeneous mass budgets for surge and non-surge glaciers indicated that glacier surges seem not have a notable impact on glacier-wide mass budget over short time scales. The spatiotemporal variability of glacier mass budgets in the UIBKK are consistent with the tendencies of winter precipitation and summer temperature. Climate warming may play more important role in glacier changes in the UIBKK.