Diagnostic Study on Impact of Sea Surface Temperature Anomalies over Tropical and Mid-latitude Pacific on Summer Low Temperature Cool Damage in Northeast China

By using the data set of the surface air temperature of 23 stations in Northeast China during the period of 1951—1997, mean monthly sea surface temperature (SST) in Pacific from 1950 to 1996 and global mean monthly wind fields from 1980 to 1994, the spatial and temporal features and its variations for summer low temperature cool damage in Northeast China are analyzed. The possible relationship and the mechanism of impact between SST anomalies in the regions of Pacific and the low temperature cool damage are also studied. The results show that the first three eigenvalues obtained by the EOF analysis (84.28% of the total variance) can basically explain the summer temperature anomalies in Northeast China. The temperature anomalies reconstructed by those three eigenvalues have three dominant scales on 3—4 years, 6—8 years and quasi-16 years. Among them, 6—8 years’ oscillation is the strongest. On inter-decadescale, three appears a jump of the temperature from cooler to warmer around 1997. The warm pool of tropical West Pacific (140° E—180°, 10° S—10° N) is a key area that affects the summer low temperature in Northeast China. The SST anomalies in last winter over that is a strong signal which could be used to predict the summer low temperature cool damage. Another key area is mid-latitude West Pacific (130° E—180°, 10°—30° N) where the SST anomalies in last spring are also closely related with summer low temperature in Northeast China.