CLIMATOLOGY AND VARIABILITY IN THE ECHO COUPLED GCM

ECHO is a new global coupled ocean-atmosphere general circulation mode l (GCM), consisting of the Hamburg version of the European Centre atmo spheric GCM (ECHAM) and the Hamburg Primitive Equation ocean GCM (HOPE ). We performed a 20-year integration with ECHO. Climate drift is sign ificant, but typical annual mean errors in sea surface temperature (SS T) do not exceed 2-degrees in the open oceans. Near the boundaries, ho wever, SST errors are considerably larger. The coupled model simulates an irregular ENSO cycle in the tropical Pacific, with spatial pattern s similar to those observed. The variability, however, is somewhat wea ker relative to observations. ECHO also simulates significant interann ual variability in mid-latitudes. Consistent with observations, variab ility over the North Pacific can be partly attributed to remote forcin g from the tropics. In contrast, the interannual variability over the North Atlantic appears to be generated locally.