Atmosphere-ocean coupled models are effective tools for research of large-scale, long time-scale climatic variations where interaction between the atmosphere and the ocean plays a crucial role. Continuous efforts have been made to develop atmosphere-ocean coupled models at the Meteorological Research Institute (MRI) of Japan Meteorology Agency (JMA). This short article is a brief introduction of these coupled models and their performance associated with the Pacific climate variations. Three types of coupled models are presented with different topics, respectively: coupled gneral circulation models (CGCMs) for ENSO simulation, hybrid coupled model (HCM) for ENSO forecast, and a CGCM for decadal variation in the north Pacific.
2.CGCMs for ENSO
Accuracy of the sea surface wind stress and heat fluxes of an atmospheric general circulation model (AGCM), or accuracy of the SST of an ocean general circulation model (OGCM) was not so seriously concerned when AGCM and OGCM were driven in a stand-alone mode with prescribed boundary conditions. However, once an AGCM and an OGCM is coupled, positive feedback can take place due to the error of these surface fluxes and the model goes to the different climatology from the observed. Climate variations produced would be directly influenced by the error of the surface fluxes, but they would be affected by the distorted model climatology as well. One pragmatic solution is to add external fluxes to maintain the climatology as the observed. However, the flux correction is suspected to modify the way of evolution of the atmosphere-ocean coupled variations, and would be avoided if possible. We constructed CGCMs without flux correction and tried to simulate tropical Pacific seasonal and interannual variations. The model
Table 1. Domain and resolution of MRI CGCMs without flux corrections
