HR: 16:24h
AN: A24A-03 INVITED    [Abstracts]
TI: Synoptic influences on Fram Strait sea ice flux
AU: * Tsukernik, M
EM: masha@ucar.edu
AF: Climate and Global Dynamics Division National Center for Atmospheric Research, PO Box 3000, Boulder, CO 80307, United States
AB: The recent decline of Arctic sea ice extent has attracted widespread scientific attention. Explanation of this decline is usually found in a combination of external (e.g. GHG) forcings and changes in atmospheric circulation patterns. Most efforts focus on large scale circulation patterns, such as the North Atlantic Oscillation and the Arctic Oscillation and their impact on sea ice. However, synoptic scale atmospheric features also play a significant role in modulating sea ice in the Arctic. I examine the influence of cyclones on sea ice export through Fram Strait - the primary region of sea ice export out of the Arctic, which accounts for about a quarter of the total freshwater export. Cyclones are identified using a tracking algorithm applied to 6-hourly NCEP/NCAR Reanalysis sea level pressure fields. Sea ice is examined using daily Polar Pathfinder Ease-Grid sea ice motion vectors and sea ice concentration fields derived from Nimbus-7, SMMR and DMSP SSM/I brightness temperatures distributed at NSIDC. A case study analysis reveals that depending on their position relative to the sea ice edge, cyclones can significantly increase or decrease (and even reverse the direction of) the sea ice flux out of Fram Strait. A statistical evaluation of the co- variability between synoptic activity and sea ice since 1979 is performed to evaluate recent trends and interannual variability in the Fram Strait region. The relationships between the synoptic-scale variability and large-scale circulation patterns such as the North Atlantic/Arctic Oscillation are also examined.
DE: 3349 Polar meteorology
DE: 3364 Synoptic-scale meteorology
DE: 4540 Ice mechanics and air/sea/ice exchange processes (0700, 0750, 0752, 0754)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting