Predictions of anomalous air-sea interaction in the Kuroshio-Oyashio Extension

Analysis of a coupled model integration suggests that low frequency variability of winter sea surface temperature, turbulent air-sea heat fluxes and precipitation in the Kuroshio-Oyashio Extension (KOE) are driven by changes of the oceanic circulation. These result from the accumulation by Rossby waves of anomalous Ekman pumping. Thus, anomalous conditions in the KOE region should be predictable from observations of North Pacific wind stress and an equivalent-barotropic Rossby wave dynamics.

This hypothesis is tested using wind stress and SST from 50 years of reanalysis data. We find that predictions of KOE SST anomalies using these dynamics have low, but nontrivial skill at lead times of one to two years. The skill exceeds that obtained from persistence and the Namias and Born reemergence hypothesis. Anomalous winter time conditions in the KOE regions, of relevance to fisheries and possibly to climate anomalies elsewhere, appear predictable a few years in advance.