A field study of mass balance and hydrology of the West Khangri Nup glacier (Khumbu, Everest).

Depiction of glaciers’ dynamics in the high altitudes of Himalaya, and hydrological fluxes therein is often limited, and yet necessary to assess their contribution to overall water budget in the downstream areas. Information about glaciers in these remote regions is often based on satellite data, which routinely document the retreat or advance of ice-covered areas, while volume changes are less easy to quantify, and require local assessment of weather, and hydrology. 
Here, we report investigation of snow accumulation, ice melt, and mass balance of the West Khangri Nup (WKN) glacier (mean altitude 5494 m a.s.l., 0.23 km²), a part of the Khumbu glacier in the Everest region. The glaciers of the area have experienced negative mass balances in the last three decades, and accordingly investigation of their recent, and prospective dynamics seems necessary. 
Weather, glaciological, snow pits, hydrologic, and isotopic data gathered during some field campaigns (2010-2014) on the glacier, and at the EVK2CNR pyramid site are used here to set up the Poli-Hydro glacio-hydrological model, to depict ice and snow melt and hydrological flows, and investigate seasonal snow dynamics on this high region of the glacier.   
Coupling ice ablation data, and Poli-Hydro simulation for ca. 5 years (January 2010-June 2014), we estimated that WKN depleted ca. -10.46 m of ice water equivalent IWE (i.e. annually ca. -2.32 m IWEy^-1). Using then snowpack density, and isotopic (δ¹⁸O) profiles on the WKN, we demonstrate that local snowpack during field surveys was recent (Fall-Winter 2013-2014), and that significant snow accumulation did not occur recently. Analysis of recent snow cover from LANDSAT images also confirms snow dynamics as depicted. 
We present original data and results, and complement present studies covering glaciers’ mass balance, and investigation of accumulation zones in the Everest region, and the Himalayas, also potentially helpful in the assessment of future dynamics under ongoing climate change.