Abstract:In this study,the atmosphere and oceanic features in association with large-scale sea surface temperature(SST) anomalies over the North Pacific in winter are examined in terms of their dominant roles in local air-sea interactions,by using NCEP/NCAR Reanalysis and Extended Reconstructed Sea Surface Temperature from the period of 1948-2014.The statistic results show that a greater number of cases of atmospheric forcing to the ocean are identified,thus indicating that atmospheric forcing to the underlying ocean plays a dominant role in local air-sea interaction over the North Pacific in winter.However,some cases for oceanic forcing to the overlying atmosphere still exist,which is indicative of oceanic feedback.In the cases for atmospheric forcing to the ocean,a dipole pattern of geopotential height anomalies(an anomaly anticyclone in the northeast,while an anomaly cyclone in the southeast),together with southeasterly and deep warm anomalies,lie only over the positive SST anomalies,which is indicative of equivalent barotropic atmospheric structures,while the opposite is true for these large-scale SST anomalies.In the cases for oceanic forcing to the atmosphere,a triple pattern of geopotential height anomalies(an anomaly anticyclone in the northwest,an anomaly cyclone in the southwest,and an anomaly cyclone in the east),along with surface easterly anomalies,are located over the positive SST anomalies.However,a pair of geopotential height anomalies(an anomaly anticyclone in the south,and an anomaly cyclone in the east),along with surface westerly wind anomalies,appear over the negative SST anomalies.Overall,the geopotential height anomalies still have the same equivalent barotropic structure features as the cases of atmospheric forcing to the ocean,yet their values are much smaller and are mainly limited to the lower troposphere.In addition,the ocean temperature anomalies propagate downward when the atmospheric forcing dominates,while they are almost stationary when the oceanic forcing plays an active role.