PI: Vladimir M. Kattsov
Voeikov Main Geophysical Observatory
7 Karbyshev Street
St. Petersburg 194021 Russia
Phone: +7 812 247 8668
Fax: +7 812 247 8661
Email: kattsov@main.mgo.rssi.ru,
kattsov@atmos.uiuc.edu
The approved AMIP II diagnostic subproject No.9 "Polar Processes and Sea Ice" (J.E.Walsh, D.Bromwich, H.Cattle, V.Kattsov, V.Meleshko, J.Maslanik) is focussed on AGCM-simulated fields that are most relevant to the forcing of sea ice. While the scope of the subproject is sufficiently broad to allow for the entrainment of additional investigators having polar interests, several foci have emerged: (1) polar clouds and radiative fluxes, (2) the polar water vapor fluxes (lateral as well as surface fluxes), and (3) downslope airflow in the vicinity of ice sheet margins. A preliminary analysis of early AMIP II results and an intercomparison of the coupled IPCC DDC simulations have revealed some systematic errors (common both to the AGCMs and AOGCMs) in simulations of surface air temperature, precipitation, and sea level pressure in the Northern Polar region (Walsh et al., 2001, in preparation). In addition, the across-model variance of near-surface atmospheric fields (e.g., temperature) appears to be larger in the IPCC DDC coupled models than in the AMIP-II models. We hypothesize that the differences in sea ice simulated by the coupled models are at least partly responsible for these differences in variance of the atmospheric fields. In order to test this hypothesis, we need to examine quantitatively the sea ice distributions in the coupled models. The CMIP archives contain sea ice distributions, in addition to the atmospheric fields required for a more complete analysis of the sea-ice atmosphere linkages. Therefore, adding CMIP model outputs to the above intercomparison would help to understand, e.g., to what extent coupling to an interactive ocean/sea-ice model can be responsible for different systematic errors in the atmospheric component (in high latitudes) of a coupled model.