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

20年前，对北极西部陆地和海洋积雪中黑碳（BC）含量的测量表明，BC可能是导致反照率下降0-4%的原因。然而，最近的测量表明，北冰洋中雪的BC含量可能发生了变化。pi提出了一项更新的泛北极调查，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、格陵兰冰盖的湿雪区和干雪区以及冰岛的冰盖上的最大雪深附近采集样本。项目人员和志愿研究人员都将参与抽样。冰川冰将在夏季在格陵兰冰盖的消融区取样，因为有证据表明它的反照率被BC降低了。将在积雪的几个垂直层次上采集雪样。在融化季节的过程中，将在一个或多个地点收集雪样，以记录BC的垂直重新分布。BC通常是疏水的。随着雪的融化，BC可能倾向于集中在地表，在那里它对反照率的影响比均匀分布的影响更大。BC对地表反照率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，以确定清除比率，这是将气溶胶排放与降水中的沉积联系起来的大气输送模型所需要的。BC在整个北极积雪中的分布及其季节变率可能通过对反照率的影响而对气候变率产生重要影响。这个项目提供的信息对气候模式的进一步发展和技能评估都是有用的。

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.