Increased influences of the SST along the Kuroshio in previous winter on the summer precipitation in northeastern China

Statistical results indicate the relationships between the SST along the Kuroshio in previous winter and the summer precipitation in northeastern China have experienced a remarkable interdecadal variation. In the 1950s and 1960s,the correlation is positive but weak,while in recent two decades the counterpart is significantly negative. In the flood or drought events in northeastern China,the SST along the Kuroshio shows quite different features and can be used as a precursory signal in climate prediction operation. The possible influencing mechanism is also analyzed in this paper. It is found the lower SST along the Kuroshio will cause an abnormal anticyclone in the lower troposphere in summer owing to the persistence of the thermal conditions of the ocean. This abnormal anticyclone will lead to an abnormal northeastly in the northwest side of the western Pacific subtropical high (WPSTH) and an abnormal southwestly in the southeast part of the northeastern cold vortex (NECV),and result in an abnormal cyclone over the WPSTH and the NECV respectively. Thus the WPSTH is weakened while the NECV is strengthened. Under this circulation pattern,more summer precipitation will be found in northeastern China. On the contrary,the warmer SST along the Kuroshio will trigger an abnormal cyclone in the lower troposphere,and strengthen the WPSTH while weaken the NECV,and finally lead to less precipitation.