北太平洋混合层深度异常及其与中国夏季降水的关系

Research on the influence of the mixed layer depth anomaly over the north Pacific on the precipitation in China in summer

利用GODAS逐月混合层深度(mixed layer depth,MLD)资料和中国160站逐月降水资料,分析了北太平洋MLD多年平均气候及异常特征,进一步研究了其对中国夏季降水年际异常的影响。结果表明:1)北太平洋30～40°N之间混合层最深,冬、春季明显大于夏、秋季。2)日期线附近的北太平洋中部海域是各季MLD年际异常共同最显著区域;仅夏季MLD年际异常与ENSO存在一定关系;秋、冬和春季MLD还存在明显年代际异常特征。3)当前冬北太平洋西部及中部MLD加深时,次年黄河下游部分地区、黄淮、江淮及长江以南大部分地区(广西南部除外)降水将偏少;河套地区、内蒙东部及东北大部降水可能偏多。

By using GODAS monthly mixed layer depth （MLD） and 160-station monthly precipitation data in China, the seasonal and interannual characteristics of MLD are analyzed over the north Pacific, along with the influences of MLD interannual anomaly on summer rainfall in China discussed. The results show that： 1 ） The MLD is the deepest over the latitudes from 30 to 40~N and is larger in winter and spring than in summer and autumn. 2） The interannual anomaly is most prominent over the middle part of the north Pacific near the international date line in four seasons;but only the MLD anomaly is somewhat related to ENSO in summer, and MLD is of interdecadal anomaly characteristics in autumn, winter and spring. 3 ） When MLD increases over western and middle part of the north and central area of Pacific in the previous winter, the precipitation may decrease over the part of the lower Yellow River, Huang-huai, Jiang-huai and to the south of the Yangtze River reaches （except the south of Guangxi） and the precipitation may increase in He-tao, east part of Neimeng and most part of Northeast China in the following year.