中国夏季降水对南印度洋偶极子的响应研究  

A Study of the Impact of South Indian Ocean Dipole on the Summer Rainfall in China

作　　者：杨明珠[1] 丁一汇[1] 

机构地区：[1]中国气象局气候研究开放实验室国家气候中心

出　　处：《大气科学》2007年第4期685-694,共10页Chinese Journal of Atmospheric Sciences

基　　金：九五"国家攀登A项目南海季风试验SCSMEX;"十五攻关--全球环境变化对策支撑技术研究项目"01课题"全球气候变化的检测和预测

摘　　要：分析了春季印度洋海表温度（SST）与中国160个站夏季降水的关系,得到：印度洋全海盆的增温趋势与我国夏季降水的气候线性变化趋势是十分一致的。另外,热带外南印度洋出现西南印度洋为正（负）、其东北部出现（负）正海温异常的分布模态时,定义为正（负）南印度洋偶极子PSIOD（NSIOD）事件。SIOD事件对中国夏季降水具有重要影响,PSIOD年,5月份中国江南和西南以及长江中下游的降水偏多;6-8月份华北、东北区域、长江中游以及华南地区降水增多,华南与华北之间的区域降水偏少,即主要为两条雨带的分布。NSIOD年,5月份中国大部降水偏少;6-8月中国西南、江南地区以及黄淮地区降水偏多。不同时段SIOD所起的作用是不同的,5月,SIOD主要通过改变马斯克林局地环流的变化,影响印度洋低层越赤道的水汽通量输送;6-8月,通过改变海洋大陆下垫面SST热状态,改变其上空对流强度以及水汽输送方向,并间接影响西北太平洋副热带高压的强度和南北位置,进而对中国雨带的分布产生影响。The relationship between the Indian Ocean sea surface temperature （SST） in spring and Chinese 160-station rainfalls during summer is investigated by using singular value decomposition （SVD） method. The results show： the first mode of SVD, that is, the most significant mode between Indian Ocean SST （the left field for SVD） mad the summer rainfalls （the right field for SVD） is interdecadal effect. That is, the warming trend exhibited in most of the Indian Ocean SST in recent fifty years has important impacts on rainfalls over China and the degree of similarity between right field heterogeneous correlation pattern of the first SVD mode and the climatological trend of the rainfalls over China is very high （reaches 0. 765）. Besides, the distribution of the significant elgenvalues of the second SVD mode of the Indian Ocean SST in spring in extratropical regions of the Indian Ocean also has notable impacts on the rainfalls over China. The Southwest Indian Ocean （50°S- 30°S, 50°E- 80°E） is defined as West Pole and the region northeast of West Pole （20°S- 10°S, 60°E- 100°E） is defined as East Pole. When the area-averaged SST anomalies are negative （positive） in West Pole and positive （negative） in East Pole, a positive （negative） South Indian Ocean Dipole （SIOD） happens. The composition analysis shows that both the PSIOD （positive SIOD） and NSIOD （negative SIOD） events have important impacts on Chinese rainfalls in late spring （May） and summer （averaged from June to August）. In PSIOD years, the rainfalls in Southwest China, the middle and lower reaches of the Yangtze River and its southern flank are intensive in late spring, and the rainfalls over Northeast China, North China, the middle reaches of the Yangtze River and South China are intensive while the rainfalls over the region between North China and Southeast China are subdued in summer. In NSIOD years, the rainfalls over most of China decrease in late spring, and the rainfalls in Southwest China,

关 键 词：印度洋海表温度 中国夏季降水 马斯克林高压 索马里急流 副热带高压 

分 类 号：P461[天文地球—大气科学及气象学]