Dynamic Linkage between the North Pacific and the Tropical Pacific: Atmosphere--Ocean Coupling

In this study, dynamic linkage of atmosphere-ocean coupling between the North Pacific and the tropical Pacific was demonstrated using a large number of ensemble perturbed initial condition experiments in a fully coupled fast ocean-atmosphere model (FOAM). In the FOAM model, an idealized mixed layer warming was initiated in the Kuroshio-Oyashio extension region, while the ocean and atmosphere remained fully coupled both locally and elsewhere. The modeling results show that the warm anomalies are associated with anomalous cyclonic winds, which induce initial warming anomalies extending downstream in the following winter. Then, the downstream warming spreads southwestward and induces SST warming in the equatorial Pacific via surface wind-evaporation-SST feedback. Warming in the tropical Pacific is further reinforced by Bjerknes’ feedback.