The field campaigns of light absorbing impurities in the seasonal snow over Northern China (Invited Presentation)

Snow is the most reflective natural surface on Earth. Its albedo can be reduced by small amounts of dark impurities, such as dust and black carbon (BC) particles; this effect is significant for climate and hydrological cycle. Two field campaigns were conducted in Northern China in the winter of 2010 and 2012. Those campaigns are the first large area survey of absorbing impurities in seasonal snow over Northern China. Snow samples were collected at 84 sites covering 8 provinces of China. The absorbing impurities in seasonal snow are mainly dust and BC particles, respectively, in Northwestern and Northeastern China. The estimated concentration of BC is low in the far north of Heilongjiang province (51oN), and similar to that found along the coast of the Arctic Ocean, 2000 km directly north, but becomes high in heavily-industrialized Liaoning, Jilin, and the southern part of Heilongjiang. It is also found that the BC contents in seasonal snow across northern Xinjiang, which have a median value of ~70 ng/g, are lower than those in northeast China but comparable to those in glaciers over Tianshan Mountains. The estimated concentration of BC at the cleanest sites in Xinjiang is 20 ng/g, which is similar to that found along the coast of the Arctic Ocean. It is also shown that the BC content of snow decreases with the altitude. The data from those field campaigns should be useful for testing transport models and climate models for the simulated BC in snow and its effect on albedo.