全球海表温度年代际尺度的空间分布及其对长江中下游梅雨的影响

SPATIAL DISTRIBUTION OF THE GLOBAL SEA SURFACE TEMPERATURE WITH INTERDECADAL SCALE AND THEIR POTENTIAL INFLUENCE ON MEIYU IN MIDDLE AND LOWER REACHES OF YANGTZE RIVER

中文关键词:  全球海表温度，长江中下游梅雨，年代际变化，空间分布 结构

英文关键词:Global SST, Meiyu in the middle and lower reaches of Yangtze River, Interdecadal change, Spatial distribution

中文摘要:

      使用统计诊断的方法，探讨了近百年全球海表温度年代际尺度的空间分布结构与长江中下游 梅雨异常变化的可能联系。采用三次样条函数拟合的方法将1885～2000年全球海表温度场和长江中下游梅雨雨量百分比序列的年代际变化分量分离出来，在分析各自年代际变化特征基 础上，研究了全球海表温度的年代际尺度分布结构对长江中下游梅雨异常变化的影响。结果 表明：(1) 全球海表温度年代际尺度变化分量清晰地表征出气候背景的分布状态，其中太平洋年代际振荡（PDO）型态表现突出，特别是1976年以后太平洋的气候背景呈现暖事 件增强的趋势。同时，印度洋及大西洋中部海域的海表温度也表现出明显的升温趋势。(2)长江中下游梅雨年代际尺度变化趋势与全球海表温度的年代际变化趋势基本一致，特别是与PDO典型分布型态的变化趋势有很好的对应，当PDO暖事件趋势处于较强时期时，长江中下游 梅雨为偏多的趋势，反之亦然。其中20世纪70年代中期PDO出现暖位相增强的突变，长江中下游梅雨也在此时期转入增多的趋势。同时，印度洋、大西洋部分地区的海表温度的年代际 变化与梅雨的年代际变化之间也有一定的关联。(3)PDO指数与西太平洋副热带高压面积指数的年代际变化趋势一致的统计事实，从一个侧面说明海洋的年代际变化最终通过副热带高压 的变动影响梅雨的异常变化的可能性。

英文摘要:

      Potential influence of spatial distribution of the global sea surface temperatur e (SST) with interdecadal scale in the last 100 years on the Meiyu anomaly in the middle and lower reaches of Yangtze River are explored by using statistic dia gnosing method. The components with interdecadal scale variation of the global S ST and Meiyu precipitation percent series during 1885-2000 are separated from their original data by the triple sample function fitting. Based on features of in terdecadal variation of them, the influence of global SST interdecadal variation on the Meiyu was analyzed. The results show as follows: (1) The spatial distrib ution of the climatic background are shown in the interdecadal components of global SST, specially, the pattern of Pacific Decadal Oscillation (PDO) are appeare d obviously in the distribution, after 1976 the ocean background in Pacific show n warming trend. At the same period the SST in Indian ocean and the middle area of Atlantic was also warming up; (2) The interdecadal variation trend of Meiyu in the middle and lower reaches of Yangtze River was consistent with that of glob al SST and there was much correspondence between the variation trend of the Meiy u and PDO. That means when PDO was in warmer phase period, it was raining in mid dle and lower reaches of the Yangtze River. When PDO occurred abrupt warming in meddle of 1970s in 20 century, the trend of the Meiyu enhanced than previous per iod. In addition, the relationship between the interdecadal variation of SST in Indian ocean and part of Atlantic and that of Meiyu was also significant; (3) Th e statistic results show that the interdecadal trend of PDO was consistent with that of subtropical high pressure zone shown that the Meiyu anomaly is influence d by the interdecadal variation of SST through the variation of subtropical high in West Pacific finally.