Coupled Model Hindcasts: Local and Remote Forcing

25 The skills of 11 coupled ocean-atmosphere general circulation models (CGCMs) are 26 investigated in the prediction of seasonal rainfall and circulation anomalies over the Northwest 27 (NW) Pacific for the period 1980-2001, with a focus on the summer following the mature phase 28 of El Niño [hereafter JJA(1)]. It is shown that the first empirical orthogonal function (EOF) 29 mode of sea level pressure (SLP) is closely tied to the second EOF mode of rainfall variability 30 over the NW Pacific during JJA(1), indicative of strong feedback between circulation and 31 convection. Most coupled models and the associated multi-model ensemble well predict these 32 EOF modes and their relationship with high fidelity. 33 Coupled models are capable of predicting suppressed rainfall over the NW Pacific in 34 JJA(1). A few models fail to predict the concurrent weak negative sea surface temperature 35 (SST) anomalies on the southeastern flank of the anomalous anticyclone. This suggests that 36 remote forcing via teleconnections is important for NW Pacific rainfall prediction in those 37 models. In some models, local air-sea interactions seem also to play a role. Specifically, remote 38 forcing by tropical Indian Ocean (TIO) SST variability is identified as influential on NW 39 Pacific climate during JJA(1). TIO SST affects the atmosphere over the NW Pacific by two 40 mechanisms, via the equatorial Kelvin wave and the intensification of the subtropical westerly 41 jet, respectively. Overall, models are successful in predicting the anti-symmetric patterns of 42 precipitation and winds over TIO during spring, which are critical to sustaining the TIO 43 warming through the subsequent summer. 44 45 46 47 48 49 3