Northeast China summer temperature and North Atlantic SST

Abstract

A previous study revealed a close relationship between interannual variations ofnortheast China (NEC) summer temperature and a tripole sea surface temperature (SST)anomaly pattern in the North Atlantic in preceding spring. The present study investigatesthe change in the above relationship and the plausible causes for the change. A tripole SSTindex is defined with its positive value corresponding to positive SST anomalies in thetropics and midlatitudes and negative SST anomalies in the subtropics. The tripole SSTanomaly pattern has a weak correlation with NEC summer temperature during the 1950sthrough the mid‐1970s, in sharp contrast to the 1980s and 1990s. This change is related tothe difference in the persistence of the tripole SST pattern. Before the late 1970s, thetripole SST pattern weakened from spring to summer, and thus, the spring North Atlantictripole SST pattern had a weak connection with NEC summer temperature. On thecontrary, after the late 1970s, the tripole SST pattern displayed a tendency of persistencefrom spring to summer, contributing to circulation changes that affected NEC summertemperature. There are two factors for the persistence of the tripole SST pattern fromspring to summer. One is the North Atlantic air‐sea interaction, and the other is thepersistence of SST anomalies in the eastern equatorial Pacific during the decay ofEl Nino–Southern Oscillation (ENSO). It is shown that the North Atlantic SST anomaliescan have an impact on NEC summer temperature independent of ENSO.