Characteristics of Khumbu Glacier, Nepal Himalaya: recent change in the debris-covered area

Abstract

Using satellite data, the longitudinal distribution of the ablation rate and flow velocity were estimated for the ablation area, where glacier ice is covered with supraglacial debris. The ablation rate, small around Everest Base Camp (EBC) just below the equilibrium line, increased down-glacier for about 3 km, then decreased gradually toward the apparent terminus, located about 10 km from EBC. The velocity decreased almost linearly from EBC to the terminus. The results allowed estimation of the recent change of ice thickness using the continuity equation. The glacier has thinned recently in the ablation area. The rate of thinning was large near EBC, where the surface is either bare ice or covered with very thin debris cover, but relatively small and rather uniform at lower sites, where the supraglacial debris layer was thick and supraglacial lakes and ice cliffs predominate. The general pattern is compatible with field observations.