MEAN CLIMATE STATE SIMULATED BY A COUPLED OCEAN-ATMOSPHERE GENERAL-CIRCULATION MODEL

The result of a 100-year integration of a coupled ocean-atmosphere gen eral circulation model (CGCM) is analyzed, and compared with that of a 25-year integration of the corresponding uncoupled atmospheric genera l circulation model (AGCM) and observed data. The large-scale circulat ion patterns of mean climate state simulated by the CGCM are in good a greement with the observed ones, although differences exit in the posi tions and intensities between the simulated and the observed patterns. Having compared the standard deviations of monthly mean sea level pre ssure simulated by the CGCM to those by the AGCM, we found that the in teraction between ocean and atmosphere mainly increases the interannua l variability in the tropics especially in summer. The CGCM can also p roduce El Nino and Southern Oscillation (ENSO) events, whereas the AGC M cannot reproduce the main features of the Southern Oscillation. This implies that the air-sea interaction may be a principal mechanism for the occurrence of ENSO phenomena. The fundamental features of simulat ed regional climates are also analyzed. The CGCM can reproduce princip al characteristics of surface air temperature and precipitation at fiv e selected typical regions (desert region, plain region, monsoon regio n etc.). The distributions of annual mean surface ait temperature and precipitation in East Asia can also be reasonably simulated.