Dust and black carbon have been nneasured in the seasonal snow across northern China to improve our understanding of the role of absorbing aerosols in the clinnate system. Much of northeastern China has a contiguous seasonal snow cover in winter and early spring, and in central and western China large areas are partly covered by thin and patchy seasonal snow. The albedo of snow is therefore a primary determinant of the climate of these regions. Because snow is the most reflective natural surface on Earth, the presence of small amounts of absorptive impurities, such as black carbon (BC) and dust particles, in snow can reduce the albedo significantly (Warren 1982). The radiative forcing caused by BC in snow has been assessed to be an important anthropogenic forcing for twentieth-century cHmate (Solomon et al. 2007). Hansen et al. (2005) identified BC in snow and ice as one of the largest sources of uncertainty in their comprehensive assessment of the various radiative forcings for climate change.
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