El Ni盛期印度夏季风水汽输送在我国华北地区夏季降水异常中的作用

通过对１９５１ ～１９９４ 年我国夏季１６０ 个站降水资料的分析，指出Ｅｌ Ｎｉ珘ｎｏ 盛期在我国华北地区具有显著的降水负异常。为了解释这种降水负异常产生的原因，利用ＮＣＥＰ／ＮＣＡＲ１９４９ ～１９９６ 年再分析资料，分析了夏季印度季风区的水汽输送在东亚季风区水汽输送中的作用。结果表明，印度季风区的水汽输送与我国华北地区的水汽输送有显著的正相关。Ｅｌ Ｎｉ珘ｎｏ期间往往对应着弱印度季风，即Ｅｌ Ｎｉ珘ｎｏ 盛期与弱印度夏季风相联系的弱水汽输送造成了我国华北地区水汽输送的减弱，使得华北地区上空大气中可降水量产生显著负异常，由此导致了负的降水异常。

THE ROLE OF INDIAN SUMMER MONSOON WATER VAPOR TRANSPORTATION ON THE SUMMER RAINFALL ANOMALIES IN THE NORTHERN PART OF CHINA DURING THE EL NINO MATURE PHASE

The analyses of the summer rainfall data of 160 stations in China for the period from 1951 to 1994 reveal that there are significant negative rainfall anomalies in the northern part of China in the period of the El Nio mature phase. In order to explain the cause of such negative precipitation anomalies, the role of the water vapor transportation of the Indian summer monsoon in that of the East Asian summer monsoon is discussed by using the NCEP/NCAR reanalysis data for the period from 1949 to 1996. The results show that the water vapor transportation of the Indian summer monsoon is significantly correlated with that over the northern part of China in summer. A weak Indian summer monsoon usually corresponds to a El Nio event. During the El Nio mature phase, the weak water vapor transportation associated with the weak Indian summer monsoon transports less water vapor to the region over the northern part of China and the significant negative precipitable water appears there, which lead to the negative precipitation in summer in the northern part of China.