HR: 10:50h
AN: C52A-03 INVITED     [Abstracts]
TI: Role of Sea Ice in a Mechanism of Arctic Decadal Variability
AU: * Dukhovskoy, D
EM: ddmitry@coaps.fsu.edu
AF: COAPS FSU, RM Johnson Building, Suite #200 2035 E. Paul Dirac Drive, Tallahassee, FL 32310 United States
AU: Johnson, M
EM: johnson@ims.uaf.edu
AF: IMS UAF, University of Alaska Fairbanks O'Neill Bldg, Fairbanks, AK 99775-7220 United States
AU: Proshutinsky, A
EM: aproshutinsky@whoi.edu
AF: WHOI, Woods Hole Oceanographic Institution Department of Phys. Oceanography, Woods Hole, MA 02543 United States
AB: This study investigates decadal variability of the Arctic Ocean - Greenland, Iceland, Norwegian Seas atmosphere-ice-ocean system. Based on findings from previous observational and modeling studies of Arctic climate it is assumed that decadal variability in the region is associated with self-sustained oscillations in the climate system. We hypothesize that Arctic variability is regulated by heat and freshwater exchange between the Arctic Ocean and the GIN Sea. The interaction between basins is weak during anticyclonic circulation regimes (low AO/NAO) and strong during cyclonic circulation regimes (high AO/NAO). Regime shifts are controlled by the system itself through oceanic and atmospheric gradients (dynamic height and surface air temperature) that increase during the anticyclonic regime and decrease during the cyclonic regime. A simple model of the Arctic Ocean and Greenland Sea, coupled to a thermodynamic sea ice model and atmospheric model, has been used to investigate a possible mechanism of self-sustained climate oscillation. Periodic solutions obtained from simulations with seasonally varying forcing, for scenarios with high and low interaction between the regions, reproduce major anomalies in the ocean thermohaline structure, sea ice volume, and fresh water fluxes attributed to ACCR and CCR. Role of sea ice in the mechanism of decadal variability is discussed.
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 3349 Polar meteorology
DE: 4215 Climate and interannual variability (3309)
DE: 4504 Air/sea interactions (0312)
DE: 4572 Upper ocean processes
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting