Glacier melting and precipitation trends detected by surface area changes in Himalayan ponds

Abstract. Climatic time series for high-elevation Himalayan regions are decidedly scarce. Although glacier shrinkage is now sufficiently well described, the changes in precipitation and temperature at these elevations are less clear. This contribution shows that the surface area variations of unconnected glacial ponds, i.e., ponds not directly connected to glaciers, can be considered suitable proxies for detecting changes in the main hydrological components of the water balance on the south side of Mt. Everest. Glacier melt and precipitation trends have been inferred by analyzing the surface area variations of ponds with various degrees of glacial coverage within the basin. In general, unconnected ponds over the last fifty years (1963–2013 period) have decreased significantly by approximately 10 %. We inferred an increase in precipitation occurred until the mid-1990s followed by a decrease until recent years. Until the 1990s, glacier melt was constant. An increase occurred in the early 2000s, and in the recent years, contrasting the observed glacier reduction, a declining trend in maximum temperature has decreased the glacier melt.