ENSO and Indian Ocean dipole mode in three coupled GCMs

The simulated ENSO and Indian Ocean dipole (IOD) mode events from three coupled GCMs with the same oceanic component model,CPM0,CPM1 and FGCM0,are compared.The only difference between the CPM0 and the CPM1 comes from the coupling scheme at the air-sea interface,e.g.,flux anomaly coupling scheme for the former and direct coupling scheme for the latter.The FGCM0 is also a directly coupled GCM,but its atmospheric component model is the NCAR CCM3 rather than the NCC T63AGCM as in the other two coupled GCMs CPM0 and CPM1.All three coupled models show El Niño-like interannual variability in the tropic Pacific,but the FGCM0 shows a bit stronger amplitude of El Niño events and both the CPM0 and the CPM1 show much weaker amplitude than the observed one.In the meanwhile,the quasi-biennial variability dominates in the FGCM0 simulations,and 4 a and longer periods are significant in both the CPM0 and CPM1 models.As the El Niño events simulated by the three coupled GCMs,the simulated Indian Ocean dipole mode events are stronger from the coupled model FGCM0 and weaker from both the CPM0 and CPM1 models than those from observation.