ECMWF ANALYSES AND PREDICTIONS OF THE SURFACE CLIMATE OF GREENLAND AND ANTARCTICA

Major weather forecast centers produce physically based large-scale cl imate analyses and predictions that can be used as proxies for missing observations and thus as full-coverage climatologies. Because of this , a global reanalysis of recent climate is being carried out at the Eu ropean Centre for Medium-Range Weather Forecasts (ECMWF). At the surfa ce of the polar ice sheets (the atmospheric boundary condition for ice evolution), observations of climate are particularly scarce. To estim ate how the new ECMWF climatology might help provide climate data over the polar ice sheets, the authors present 6 years of previously analy zed surface temperature and predicted precipitation for both Greenland and Antarctica. Analyses are the result of 6-h forecasts corrected to fit with reports from weather stations. Predicted variables are not c orrected but the observation-constrained analyzed fields are used to i nitialize forecasting cycles. In spite of a 'sparse coverage of the ob servation network, the analyzed temperature, including seasonality, is very reasonable. interannual variability, however, appears greater th an suggested by satellite observation. Mean annual precipitation in An tarctica is fairly well represented, but it is difficult to determine whether a lack of seasonality on the plateau is reasonable or not. Pre cipitation in coastal Greenland is often too high, and accumulation mi ght be low inland. Mean predicted accumulations, 1594 X 10(12) and 539 X 10(12) kg yr(-1), over the Antarctic and Greenland ice sheets, resp ectively, are in good agreement with previous estimates. It is reasona ble to expect that the reanalysis will largely satisfy the need for a full-coverage gridded climatology of the two polar ice sheets.