Modulation of Atmospheric Response to North Pacific SST Anomalies under Global Warming: A Statistical Assessment

Abstract

n this study the modulation of ocean-to-atmosphere feedback over the North Pacific in early winter from global warming is investigated based on both the observations and multiple climate model simulations from a statistical perspective. It is demonstrated that the basin-scale atmospheric circulation displays an equivalent barotropic ridge in response to warm SST anomalies in the Kuroshio?Oyashio Extension (KOE) region. This warm SST?ridge response in early winter can be enhanced significantly by global warming, indicating a strengthening of air?sea coupling over the North Pacific. This enhancement is likely associated with the intensification of storm tracks and, in turn, the amplification of atmospheric transient eddy feedback in a warm climate, although the secular trend of enhanced storm-track activity over the North Pacific is suggested to be biased in reanalysis product.