HR: 0800h
AN: U41A-0001    [Abstracts]
TI: Selection of Super-Ensembles for Regional Climate Projections
AU: Wang, M
EM: muyin.wang@noaa.gov
AF: University of Washington/JISAO, 7600 Sand Point Way NE, Seattle, WA 91115, United States
AU: * Overland, J E
EM: james.e.overland@noaa.gov
AF: NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle, WA 98115, United States
AU: Walsh, J E
EM: jwalsh@iarc.uaf.edu
AF: International Arctic Research Center, 930 Koyukuk Drive, Fairbanks, AK 99775, United States
AU: Kattsov, V
EM: kattsov@mail.ru
AF: Voeikov Main Geophysical Obsevatory, 7 Karbyshev St, St Petersburg, 194021, Russian Federation
AU: Furevik, T
EM: tore.furevik@gfi.uib.no
AF: Geophysical Institute/University of Bergen, Eastwing 305, Bergen, 5007, Norway
AB: Increased confidence in climate projections comes from removal or weighting of outlier models by comparing historical simulations against observations, and from developing multi-model statistics (super-ensembles) to accounting for structural uncertainty. The CMIP3 provides a platform for testing these hypotheses. We have used a selection criterion based on variance for 20th century Arctic surface temperatures and North Pacific sea surface temperature (SST), and mean ice area for regional sea ice. For Alaska, we considered a multivariate criterion based on the seasonal cycles of temperature, pressure and precipitation. Applying model selection criteria, we have some confidence that the SST trend in the North Pacific will emerge from natural variability and that sea ice area will be reduced by 40 percent in most Arctic marginal seas by 2050. Regionally, the models that best capture the seasonal cycles of present-day Alaskan climate project larger Arctic changes than the all-model composite. For northern Eurasia projected differences in temperatures with and without model discrimination were negligible. No one model or group of models appears to be "best" for multiple criteria or multiple regions, a remaining philosophical difficulty.
DE: 0750 Sea ice (4540)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1621 Cryospheric change (0776)
DE: 1625 Geomorphology and weathering (0790, 1824, 1825, 1826, 1886)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
SC: Union [U]
MN: 2007 Fall Meeting