| Summary: | This project involves long-term core measurements of the Arctic atmosphere, snow and other Earth system components at the Summit Greenland Environmental Observatory (GEOSummit). GEOSummit was the site of the GISP2 ice core, completed in 1993, and has been a site of atmospheric, snow and other geophysical measurements ever since. It is currently the only high-altitude site for atmospheric and related measurements in the Arctic. As global atmospheric temperatures rise, the Arctic environment is expected to undergo more rapid change in response to human influences than are other parts of the Earth system, in part due to feedbacks related to decreasing snowcover and sea-ice extent. Observed changes in Arctic temperature, atmospheric chemistry and atmospheric circulation are expected to have potentially broad but uncertain effects on Arctic systems. A number of processes that could amplify atmospheric change need consistent measurements and systematic study. For example, recent evidence indicates that important atmospheric chemical constituents undergo temperature-dependent exchange with ice/snow, and that some species are photochemically transformed and/or produced within the sunlit surface snowpack. Because changes in Arctic atmospheric circulation are cyclic over 4-5 year or longer times, long-duration measurements are needed to understand circulation and to place observed changes in a long-term perspective.
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