Black carbon in Arctic snow and ice and its effect on surface albedo

Warren 0612636二十年前，对北极西部陆地和海洋雪中黑碳（BC）含量的测量表明，BC可能导致0- 4%的CO2减少。 然而，最近的测量表明，北冰洋雪中的BC含量可能已经发生了变化。 PI建议进行更新的泛北极调查，在此期间，将在北冰洋最大积雪深度附近，俄罗斯，阿拉斯加和加拿大的苔原地区，格陵兰冰盖的湿雪和干雪区以及冰岛的冰盖上采集样本。 项目工作人员和志愿研究人员都将参与取样工作。 夏季将在格陵兰冰盖消融区对冰川冰进行取样，因为有证据表明，格陵兰冰盖的冰量因公元前而减少。将在积雪的几个垂直高度采集雪样。 在融化季节期间，将在一个或多个地点收集雪样，以记录BC的垂直再分布。 BC通常是疏水性的。 随着雪的融化，BC可能倾向于集中在表面，在那里它比均匀分布时对雪的影响更大。BC对地表径流的影响将按区域和季节进行估计。 与降雪事件同时进行的空气采样将在一个或多个地点进行，以确定清除率，这是需要在大气传输模型，链接气溶胶的排放量，沉积在precipitation.The BC整个北极雪团的分布及其季节性变化可能有重要的影响，气候变率，由于它们对CO2的影响。 该项目提供的信息将有助于进一步发展气候模式和评估气候模式的技能。

Warren 0612636Two decades ago, measurements of the black carbon (BC) content of snow on land and sea in the western Arctic suggested that BC was responsible for possible reductions of albedo of 0-4%. However, more recent measurements suggest that the BC content of snow in the Arctic Ocean may have changed. The PIs propose an updated, pan-arctic survey, during which samples will be taken near the time of maximum snow depth on the Arctic Ocean, in tundra areas of Russia, Alaska, and Canada, in both wet-snow and dry-snow zones of the Greenland Ice Sheet, and on ice caps in Iceland. Both project personnel and volunteer researchers will be involved in the sampling. Glacier ice will be sampled in summer in the ablation zone of the Greenland Ice Sheet, since there is evidence that its albedo is reduced by BC. Snow samples will be taken at several vertical levels through the snowpack. At one or more locations snow samples will be collected over the course of the melting season, to document the vertical redistribution of BC. BC is usually hydrophobic. As the snow melts, BC may tend to concentrate at the surface, where it has a greater effect on albedo than if uniformly distributed. The effect of BC on the surface albedo will be estimated both regionally and seasonally. Air sampling concurrent with snowfall events will be carried out at one or more locations, to determine the scavenging ratio, which is needed in atmospheric transport models that link emissions of aerosols to deposition in precipitation.The distribution of BC throughout the arctic snowmass and its seasonal variability may have important effects on climate variability due to their influence on albedo. The information provided by this project will be useful both for the further development and for the skill assessment of climate models.