热带和中纬太平洋海温异常对东北夏季低温冷害影响的诊断分析研究

DIAGNOSTIC STUDY ON IMPACT OF SEA SURFACE TEMPERATURE ANOMALIES OVER TROPICAL AND MID LATITUDE PACIFIC ON SUMMER LOW TEMPERATURE COOL DAMAGE IN NORTHEAST CHINA

利用１９９５～１９９７ 年东北地区２３ 个测站的地面气温资料、１９５０～１９９６ 年太平洋地区月平均海温资料以及１９８０～１９９４ 年全球月平均风场资料，分析了东北夏季低温冷害的时空特征和变化规律，探讨了太平洋各区域的海温异常与低温冷害之间的可能联系及其影响机理．结果表明，用ＥＯＦ分解得到的前三个特征向量（占总方差的８４．２８％ ）基本表示了东北夏季气温的变化，用这三个特征向量重建的气温距平场，存在着３～４ 年、６～８ 年和准１６ 年的主周期，其中６～８ 年的主分量信号最强．在年代际尺度上，在１９７９ 年前后发生了由气温偏冷向偏暖的突变．热带西太平洋暖池（１４０°Ｅ～１８０°，１０°Ｓ～１０°Ｎ）是影响东北夏季气温的关键海域，那里前期冬季海表温度变化是预测东北夏季低温冷害的强信号．另一个关键海域是中纬西太平洋（１３０°Ｅ～１８０°，１０°～３０°Ｎ），前期春季的海温变化也与东北夏季低温有较密切的联系．

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 temperatute 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 yeats. Among them, 6-8 years′ oscillation is the strongest.On inter decadescale, there appears a jump of the temperature from cooler to warmer around 1979. 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 area 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.