Geodetic mass balance estimates of 49320 glaciers in the High Mountain Asia (2000-2018)

Glacier melt-water from the High Mountain Asia (HMA) is an important supply of freshwater resources for billions of humans in South and East Asia, and certainly contributes to sea level rise. However, the HMA glacier mass balance during recent decades remains debated. Geodetic method, which is based on a comparison of DEMs acquired in different times, has proven to be an effective method for estimating decade-average glacier mass balance in mountainous regions. By employing thousands of pairs of the Chinese ZY-3 stereo data and the SRTM-C DEM, we provided the geodetic estimates of glacier mass balances and glacier-wide mean surface elevation changes between 2000 and 2018 for 49320 glaciers in the HMA. Moreover, we have validated the estimated glacier mass balances by comparing our results to field measurements and previously published estimates. In the period 2000-2018, most glaciers (42410) experienced a mass loss during the studied period, whereas glacier mass gain was only extracted for 6910 glaciers. Basically, mass loss is more serious for glacier facing north than south. Moreover, glacier mass balance estimates in 1˚×1˚ grids revealed an eastward increase in glacier mass loss, which is probably related to the temporal trend in annual snowfall. Overall, total glacier mass loss of -29.3±2.6 Gt yr-1 was estimated for the entire HMA between 2000 and 2018.