HR: 0800h
AN: C11B-0454    [Abstracts]
TI: Impact of a Changing Snow Cover on the Development of Arctic Sea Ice Albedo in Spring and Summer
AU: * Petrich, C
EM: chris.petrich@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775, United States
AU: Eicken, H
EM: hajo.eicken@gi.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775, United States
AB: The energy budget and climate of the Arctic region are significantly affected by the variable surface albedo in spring and summer. The albedo of Arctic sea ice decreases dramatically throughout spring as the snow cover on sea ice melts and melt ponds develop at the sea ice surface. This process is implicit in climate model parameterizations of sea ice albedo, based on observations under present-day snow and ice conditions. However, the validity of such parameterizations is questionable if the snow cover on sea ice changes. In order to assess the sensitivity of sea ice albedo on the snow cover, we examine surface melt, meltwater percolation, and melt pond development in the light of mechanical, fluid-dynamical, and thermodynamic processes. Specifically, we consider how melt pond development is affected by a snow cover of inhomogeneous thickness. Preliminary results indicate that mechanical deflection of the ice surface due to snow loading is capable of inducing a lateral meltwater flow at the ice--snow interface if snow patches are at least approximately 30 m in lateral extent. A model of heat and fluid transfer through ice suggests that different ice warming rates under snow cover of variable depth results in lateral variations in the permeability structure of sea ice. Lateral meltwater redistribution is enhanced once the sea ice warms and the lateral and vertical permeability of the sea ice increase. While field observations of these processes appear to be lacking to date, we postulate that these processes work in concert to control the early melt evolution of ponding and hence ice albedo. Eventually, the melt pond distribution is fixed in place by preferential ablation of sea ice that is covered by meltwater.
DE: 0700 CRYOSPHERE (4540)
DE: 0736 Snow (1827, 1863)
DE: 0750 Sea ice (4540)
DE: 1630 Impacts of global change (1225)
SC: Cryosphere [C]
MN: 2007 Fall Meeting