HR: 13:55h
AN: C23B-02 INVITED    [Abstracts]
TI: Snow on Arctic sea ice: Updating the climatology and assessing its impact on ice ablation
AU: * Eicken, H
EM: hajo.eicken@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, P.O. Box 757320, Fairbanks, AK 99775-7320, United States
AU: Harbeck, J P
EM: jharbeck@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, P.O. Box 757320, Fairbanks, AK 99775-7320, United States
AU: Perovich, D K
EM: donald.k.perovich@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory, 72 Lyme Rd., Hanover, NH 03755, United States
AB: The Arctic sea-ice cover is undergoing a major transformation with perennial ice extent decreasing at a rate of more than 8% per decade since 1979 and onset of seasonal ice formation delayed over much of the Arctic shelf seas. In this presentation we will (1) discuss the role of snow and its variability in summer surface ice melt, and (2) examine whether any significant changes are detectable in the depth or characteristics of the snow cover on Arctic sea ice based on measurements compiled for the time period from the 1960s onward. The importance of snow as a thermal insulator that constrains conductive heat flux and hence ice growth is well recognized. Less understood is its role in controlling surface melt and evolution of ice albedo. Studies of the evolution of melting landfast and drifting sea ice indicate that snow depth is a key variable that drives the initial evolution of surface melt ponds during summer. The latter in turn controls ice albedo over much of the melt season. Studies of ice melt indicate three primary controlling mechanisms, i.e. the role of snow in retarding ice surface warming, concealing surface melt water accumulation and in governing the formation of superimposed ice which in turn is critical to retention of melt water at the ice surface. Long-term studies at Barrow, Alaska suggest that through these mechanisms snow-depth variations are responsible for significant interannual variability in ponding and ice albedo. Based on field studies in the Alaskan Arctic and analysis of snow depth data compiled from icebreaker cruises, drifting stations and Russian "Sever" aircraft landings, snow depth patterns in the Arctic are examined, in particular in comparison with the climatology derived by Warren et al. (1999) from Russian drifting stations. Regional and temporal variations are discussed in the context of sea ice and precipitation changes as well as their potential impact on ice ablation patterns.
DE: 0736 Snow (1827, 1863)
DE: 0748 Ponds
DE: 0750 Sea ice (4540)
DE: 1863 Snow and ice (0736, 0738, 0776, 1827)
SC: Cryosphere [C]
MN: 2007 Fall Meeting