Black Carbon (BC) in the snow of glaciers in west China and its potential effects on albedos

Black carbon concentrations in the snow collected from some selected glaciers in west China during 2004–2006 were measured. Higher concentrations appeared at lower sites, possibly due to the topography (e.g. altitude) effect. BC concentrations in snow of Tienshan Mountains outside the Tibetan Plateau (TP) were generally higher than those inside the TP, and strong melting in spring added on more regional/local emissions from the inner TP might both contribute higher concentrations for the central TP than those on the margin of the TP. Comparison between global measured BC concentrations in snow/ice suggested the distance of the sampling site away from strong BC-emitting areas (north mid-latitudes) could be responsible for BC concentrations in snow/ice. A rough estimate for the reduced albedos in some glaciers suggested BC deposited in the surface might accelerate the melt of these glaciers in west China, e.g. HXR48 and MEG3 which were strongly contaminated by BC in their surfaces, the reduced albedos were over 5% due to the BC deposits.