An Introduction to the Integrated Climate Model of the Center for Monsoon System Research and its simulated influence of El Niño on East Asian-western North Pacific climate

This study introduces a new global climate model—the Integrated Climate Model (ICM)—developed for the seasonal prediction of East Asian-western North Pacific (EA-WNP) climate by the Center for Monsoon System Research at the Institute of Atmospheric Physics (CMSR, IAP), Chinese Academy of Sciences. ICM integrates ECHAM5 and NEMO2.3 as its atmospheric and oceanic components, respectively, using OASIS3 as the coupler. The simulation skill of ICM is evaluated here, including the simulated climatology, interannual variation, and the influence of El Niño as one of the most important factors on EA-WNP climate. ICM successfully reproduces the distribution of sea surface temperature (SST) and precipitation without climate shift, the seasonal cycle of equatorial Pacific SST, and the precipitation and circulation of East Asian summer monsoon. The most prominent biases of ICM are the excessive cold tongue and unrealistic westward phase propagation of equatorial Pacific SST. The main interannual variation of the tropical Pacific SST and EA-WNP climate—El Niño and the East Asia-Pacific Pattern—are also well simulated in ICM, with realistic spatial pattern and period. The simulated El Niño has significant impact on EA-WNP climate, as in other models. The assessment shows ICM should be a reliable model for the seasonal prediction of EA-WNP climate.