Enhanced Wintertime Surface Heat Flux Feedback in the North Pacific Over Six Recent Decades

Abstract Sea surface temperature (SST)–heat flux feedback refers to a surface heat flux response to SST anomalies. Under global warming, an overall weakening trend of SST–heat flux feedback over global oceans has been reported. However, the seasonality of the feedback change remains unknown. In this study, the wintertime air–sea feedback in the North Pacific is estimated over the past six decades, and a notable increasing trend is found. The air–sea specific humidity difference is the key determinant of the trends in the SST–heat flux feedback process. While the wind speed and air–sea temperature difference are secondary factors, the enhanced ocean eddy heat transport mechanism in the Kuroshio Extension also plays a contributing role. These findings suggest that trends in specific seasons could run opposite to the overall trend and should be considered in impact assessments.