Spatial differences of ice volume across High Mountain Asia

Advanced knowledge of glacier ice volume is vital for water resource assessment. Previous studies have focused on the estimation of ice volume, but the quantitative understanding of the spatial variability of ice volume across High Mountain regions is currently lacking. Here, we used global-scale ice thickness, debris cover and equilibrium line data to analyse ice-volume differences at various scales across High Mountain Asia (HMA). The results showed that 6.3% of the HMA glaciers are covered by debris, with debris area and volume accounting for 9% and 13.8% of the total glacier area and volume, respectively. An average debris-cover volume ratio of 13% was observed. The spatial distribution of ice volume across the HMA varies considerably from region to region. The ice volume is predominately distributed on north-facing slopes and accounts for approximately 38% of the total. It is very common in Altay and Sayan, East Tian Shan, West Kunlun, East Kunlun and Qilian Shan. Meanwhile, ice volumes in the Himalayas and Hengduan Shan are mainly distributed on the southeast aspect. Relative weight functions showed that glacier area, maximum length and average thickness are closely related to ice volume, with average relative weights of 63.7%, 22.5% and 9.8%, respectively. This study is important for the evolution of glacier volume and water resource assessment.