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.

The ground ice content in permafrost serves as one of the dominant properties of permafrost for the study of global climate change, ecology, hydrology and engineering construction in cold regions. This paper initially attempts to assess the ground ice volume in permafrost layers on the Qinghai-Tibet Plateau by considering landform types, the corresponding lithological composition, and the measured water content in various regions. An approximation demonstrating the existence of many similarities in lithological composition and water content within a unified landform was established during the calculations. Considerable knowledge of the case study area, here called the Source Area of the Yellow (Huanghe) River (SAYR) in the northeastern Qinghai-Tibet Plateau, has been accumulated related to permafrost and fresh water resources during the past 40 years. Considering the permafrost distribution, extent, spatial distribution of landform types, the ground ice volume at the depths of 3.0-10.0 m below the ground surface was estimated based on the data of 101 boreholes from field observations and geological surveys in different types of landforms in the permafrost region of the SAYR. The total ground ice volume in permafrost layers at the depths of 3.0-10.0 m was approximately (51.68 +/- 18.81) km(3), and the ground ice volume per unit volume was (0.31 +/- 0.11) m(3)/m(3). In the horizontal direction, the ground ice content was higher in the landforms of lacustrine-marshland plains and alluvial-lacustrine plains, and the lower ground ice content was distributed in the erosional platforms and alluvial-proluvial plains. In the vertical direction, the volume of ground ice was relatively high in the top layers (especially near the permafrost table) and at the depths of 7.0-8.0 m. This calculation method will be used in the other areas when the necessary information is available, including landform type, borehole data, and measured water content.