HR: 11:40h
AN: OS11B-06 INVITED     [PDF]
TI: Predicting the Extent of Summer Sea Ice in the Arctic
AU: * Rigor, I G
EM: ignatius@apl.washington.edu
AF: Polar Science Center, Applied Physics Laboratory, University of Washington, 1013 NE 40th St, Seattle, WA 98105-6698
AU: * Rigor, I G
EM: ignatius@apl.washington.edu
AF: Department of Atmospheric Science, University of Washington, Box 351640, Seattle, WA 98105-1640
AU: Wallace, J M
EM: wallace@atmos.washington.edu
AF: Department of Atmospheric Science, University of Washington, Box 351640, Seattle, WA 98105-1640
AB: The summers of 1998 and 2002 had the least sea ice extent (SIE) in the Arctic. These observations seem to agree with the trends noted by Parkinson, et al. (1999, hereafter P99) for the period 1979-1997, but the spatial pattern of these recent decreases in summer SIE were different. The summer trends shown by P99, exhibit large decreases in SIE primarily in the East Siberian Sea (ESS), while the decreases observed during 1998 and 2002 were much larger in the Beaufort and Chukchi seas (BCS). We now show that the trends for the period 1979 - 2002 are much smaller in the ESS than the trends shown by P99, and the largest decreasing trends have shifted from the ESS to the BCS. Rigor, et al. (2002) showed that the changes in SIE that P99 noted were driven by changes in atmospheric circulation related to the phase of the prior winter Arctic Oscillation (AO, Thompson and Wallace, 1998) index. Given that the latest trends in SIE are different than those shown by P99, one could ask whether the affect of the AO on sea ice noted by Rigor, et al. (2002) has also changed, and whether some large scale climate modes other than the AO has influenced the climate of the Arctic Ocean more? To answer these questions, we applied Empirical Orthogonal Function (EOF) analysis on the September SIE data from microwave satellites, and found that the first two modes SIE were most highly correlated to the prior winter AO, and the AO index of the summer months just prior to each September. These modes explain more than 45% of the variance in SIE, and show that the influence of the winter and summer AO dominates Arctic climate from 1979 - 2002. Using data from the International Arctic Buoy Programme and the National Centers for Environmental Prediction, we will show that the changes in sea ice extent are primarily driven by dynamic changes in sea ice thickness and discuss the implications for predicting summer SIE.
UR: http://iabp.apl.washington.edu/SeaIceAO/
DE: 1640 Remote sensing
DE: 1836 Hydrologic budget (1655)
DE: 1863 Snow and ice (1827)
DE: 4540 Ice mechanics and air/sea/ice exchange processes
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting