南极涛动与江淮梅雨异常的时滞相关分析

Time Lag Correlation Analyses of Antarctic Oscillations and Jianghuai Meiyu Anomaly

利用NCEP/NCAR再分析资料和中国160站月降水资料,分析了4—5月南极涛动(AAO)的变化对后期中国东部夏季降水的影响。结果表明:年际时间尺度上,4—5月平均的AAO指数与6—7月长江流域降水的相关系数为0.31,达到95%的置信水平。前期AAO偏强时,后期6—7月长江流域降水将增加,反之亦然。前期AAO的变化通过影响后期夏季西北太平洋副高的强度和位置,引起中国夏季风雨带位置的南北偏差。

Using the NCEP/NCAR reanalyzing data and the monthly rainfall data at 160 stations in China from 1958 to 2000 ,this paper analyzes the influence of the variation of AAO in April and May on summer precipitation in the east of China. The results are as following： the correlation coefficient,on interannual scale, between averaged AAO index over April-May and June-July rainfall in the Yangtze River is 0. 31, which is significant at the 95 % confidence level. When the April-May AAO is stronger,the subsequent June-July precipitation in the Yangtze River will increases, and v. v.. The change of AAO in April and May will impact the June-July intensity and position of the northwest Pacific subtropical high, thus affecting the south-north position of the summer monsoon rainbelt in China.