HR: 08:30h
AN: GC21A-03    [Abstracts]
TI: Evaluation of Coupled Climate Simulations over the Arctic for IPCC AR4
AU: * Wang, M
EM: muyin.wang@noaa.gov
AF: JISAO/University of Washington, 7600 Sand Point Way NE, Seattle, WA 98115 United States
AU: Overland, J E
EM: james.e.overland@noaa.gov
AF: NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattel, WA 98115 United States
AB: There were observed warm anomalies in surface air temperature (SAT) in the Arctic between 1920-1950 and again at the end of the century. The ability to reproduce this decadal variability in the coupled GCMs is important for understanding processes in the arctic climate system and increasing the confidence in the IPCC model projections into the future. Our study evaluated 55 ensemble runs generated by 18 coupled GCMs from around the world for their 20th century simulations (20C3M), and their corresponding control simulations (PIcntrl). Warm anomalies in the Arctic during the last two decades are reproduced by most ensemble members, but with considerable variability in magnitude between models. Among the 18 models, 12 of them generated events which were typical of mid-century arctic-wide warm anomalies (60-90oN), yet with large region-to-region, season-to-season and year-to-year variability. Control runs (without external forcing) for 14 out of 18 models also produced typical arctic multi-year temperature anomaly events. We conclude that these models were in part simulating the large intrinsic variability of the arctic atmospheric circulation and feedback mechanisms of the earlier period, similar to our previous analysis of observed SAT. Also encouraging was that the models which performed the best with regard to multi-year warm anomalies also had better simulations of the annual cycle of arctic sea ice, suggesting incorporation and influence of arctic feedback processes.
DE: 0798 Modeling
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
SC: Global Climate Change [GC]
MN: Fall Meeting 2005