A comparison of data from atmospheric research stations at Summit, Greenland, and Zeppelin, Svalbard

Researchers from the U.S. and Norway have recently started an informal collaboration to share re-sources used to interpret atmospheric chemistry data and exploit data together from the Summit, Greenland and Zeppelin, Svalbard stations (Sjostedt et al., 20 06; Stohl et al., 2006). SUMSVAL shall strengthen this collaboration between the research communities. The two stations have contrasting characteristics: Zeppelin, at rather low elevation, is in the direct outflow of pollution from Eurasia and sees freque nt episodes of so-called Arctic Haze. Summit, in contrast, is located at high altitude and sees little influence from Arctic Haze but is well positioned to sample the Arctic free troposphere. Summit is also influenced frequently by biomass burning polluti on plumes from North America, which are less pronounced at Zeppelin. A comparison of the data from these two stations, therefore, is likely to enhance our general understanding of air pollu-tion in the Arctic and its effects on Arctic climate. This projec t shall build closer links between Norwegian and U.S. researchers by conducting joint data interpretation, developing transport cli-matologies, and coordinating research activities. Extended visits of NILU researchers in the U.S., and invited travel of U. S. researchers to NILU and Svalbard are foreseen.