Possible impact of the autumnal North Pacific SST and November AO on the East Asian winter temperature

摘要

This study investigates the effects of the North Pacific sea surface temperature (NP SST) anomalies on the East Asian winter temperature (T EA), and the relationship between the Arctic Oscillation (AO) and NP SST anomalies in association with T EA. Time-lagged correlation analysis revealed that the third mode of the September-October-November (SON) mean NP SST ("SON SST 3rd mode") and the AO index for November ("Nov AO") are closely related to T _(EA), and further that the first and second modes of NP SST are associated with the Pacific Decadal Oscillation (PDO) and Pacific North America (PNA) patterns, respectively. This study reveals that when the SON SST 3rd mode and Nov AO have a positive (negative) phase, the intensity of the Siberian High weakens (strengthens), which in turn weakens (strengthens) the East Asian winter monsoon (EAWM), resulting in a warm (cold) winter in East Asia. Our results suggest that the North Pacific Ocean signals influence the AO, which is one of the most pronounced Northern Hemispheric atmospheric global patterns. Such an influence in turn governs the continental-scale circulation over Siberia and affects the subsequent local climate variation over the East Asia regions.