热带印度洋-太平洋热力异常联合模对我国夏季降水的影响

IMPACTS OF THE TROPICAL INDIAN-PACIFIC OCEAN THERMODYNAMIC ANOMALY JOINT MODE ON THE SUMMER RAINFALL OVER CHINA

基于我国160个台站的降水资料和西太平洋副热带高压指数,利用典型相关分析和合成分析等方法,研究了热带印度洋-太平洋热力异常联合模对我国夏季降水的影响,并探讨了该联合模与西太平洋副热带高压的关系。结果表明,该联合模对我国夏季降水有一年到半年的超前影响,且以冬季联合模对次年夏季降水的影响最显著。当冬季联合模出现正异常时,次年夏季我国四川地区、长江流域、华北南部降水偏多,而华北北部和江南大部分地区降水偏少;反之亦然。进一步分析表明,冬季热带印度洋-太平洋热力异常联合模对我国夏季降水的影响可能是通过夏季西太平洋副热带高压的变动来实现的。

Based on the monthly mean precipitation data at 160 observational stations of China and the Western Pacific Subtropical High（WPSH） index, the impacts of the tropical Indian-Pacific Ocean thermodynamic anomaly joint mode（IPHAM） on the summer rainfall over China are studied by using the methods of canonical correlation analysis and composite analysis, and the relationship between the IPHAM and WPSH is discussed. The results show that IPHAM has an important influence on the summer rainfall over China with a time-lead from one year to six months. Namely, summer rainfall increases in Sichuan area, Yangtze River Valley and the south of North China, but decreases in the north of North China and a large part of the regions south of Yangtze River when the IPHAM is positive in winter and vice versa when it is negative. These results indicate that the impacts of the IPHAM on the summer rainfall over China are possibly made through the variation of the WPSH in summer.