Spatiotemporal heterogeneity and driving mechanisms of Himalayan glacier mass change in the early 21st century

Abstract

Glaciers in the Himalayan mountain ranges contain huge amounts of water and are essential for the water security of their downstream basins. Due to the spatiotemporal heterogeneity and uncertainty of the glacier mass change (GMC) in the Himalayas, more refined and deeper investigations on the GMC and its driving forces are needed to complement the current research. We present the mass balance of Himalayan glaciers during 2000 to 2013 using the latest global digital elevation models; this method focuses on establishing a high-coverage result of the GMC and resolving the problems of timestamps and penetration uncertainties. The GMC of the entire Himalayas is −0.32 ± 0.15 m w.e.yr − 1; most of the lost mass drains into the Indus and Ganges river basins. Glacier mass loss gradually decreases from east to west, with the East and Central Himalayas exhibiting the highest heterogeneity in the vertical and horizontal directions, respectively. We propose two multivariate regression models with 12 potential driving factors that explain 63% to 89% of the GMC across different regions of the Himalayas. Precipitation significantly influences changes in glacier mass throughout the Himalayas, whereas debris coverage and glacier size have insignificant effects on changing the glacier mass. Our analysis reveals that seasonal climate-driven changes in the glacier mass of the Himalayas may threaten the downstream water supply.