Inter-model differences in the amplitude of Ningaloo Niño in the CMIP5 models

Ningaloo Niño is a newly identified climate mode off the west coast of Australia. In this study, the ability of 17 models that participated in the Coupled Model Inter-comparison Project, phase 5 (CMIP5) to simulate Ningaloo Niño is investigated. We find that many models can successfully simulate the observed spatial pattern of positive (negative) SST anomalies during Ningaloo Niño (Niña). In addition, its seasonality as well as associated wind and rainfall anomalies are well reproduced. However, simulated amplitude of Ningaloo Niño varies among the models. To examine the root causes of this bias, we have quantified the strength of processes that contributes to the generation and development of Ningaloo Niño. We show that the difference in the amplitude is mainly caused by inter-model differences in the sensitivity to remote influences from the ENSO, rather than those in the strength of the local air-sea feedback. In particular, the difference in the strength of the oceanic teleconnections from the ENSO is more important in determining the simulated amplitude than that of the atmospheric teleconnections. Possible remedies for the above model bias will also be presented.