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

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可能导致了反照率的0-4%的减少。然而，最近的测量表明，北冰洋的雪中BC含量可能已经发生了变化。PIS提出了一项最新的泛北极调查，在此期间，将在北冰洋、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帽附近采集样本。项目人员和志愿者研究人员都将参与抽样。夏季将在格陵兰冰盖的消融区对冰川冰进行采样，因为有证据表明其反照率在公元前减少。积雪样本将通过积雪在几个垂直层面上进行采集。在一个或多个地点，将在融化季节的过程中收集雪样，以记录BC的垂直重新分布。BC通常是疏水性的。随着积雪的融化，BC可能倾向于集中在表面，在那里它对反照率的影响比均匀分布时更大。BC对地表反照率的影响将在区域和季节两个方面进行估计。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，以确定大气传输模型中所需的清扫率，该模型将气溶胶的排放与降水中的沉积联系起来。由于BC在整个北极雪团的分布及其季节变化对反照率的影响，因此可能对气候变异性产生重要影响。该项目提供的信息将有助于气候模型的进一步发展和技能评估。

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.