NP-seminar: Snow Impurity and Glacial Microbe effects on the abrupt warming in the Arctic
Many climate models cannot accurately simulate the recent abrupt melting of snow/ice in the Arctic. One of the possible causes is albedo reduction of snow/ice surface by light absorbing snow impurities such as black carbon (BC) and dust, including glacial microbes. To clarify that "Snow Impurity and Glacial Microbe effects on the abrupt warming in the Arctic (SIGMA)" Project has started since 2011. The first SIGMA intensive field observation has been carried out at the site SIGMA-A (78°03'N, 67°38'W, 1,490 m a.s.l.) on northwestern Greenland ice sheet during the period 26 June – 16 July 2012. We have installed automatic weather station and have conducted meteorological and glaciological measurements. In this seminar we will discuss on the preliminary results of possible albedo reductions due to snow impurities and snow grain growth with the data at SIGMA-A using physically based snow albedo model (PBSAM). The results show the former effect does not have a significant impact on the albedo reduction at SIGMA-A, whereas the latter is much larger than the former effect. This indicates increase in air temperature caused by global warming could accelerate snow metamorphism by which snow grain growth reduces the albedo (snow - albedo feedback) and could enhance the snow melting.