新疆地区夏季降水异常的时空特征及环流分析

Analysis of Temporal Spatial Features and Circulation Characteristics of Summer Precipitation in Xinjiang

利用中国160个站1951-2000年逐月降水资料，对新疆地区近50a来夏季降水异常的时空特征及环流形势进行了研究。考虑到新疆地区复杂的地形，将新疆地区分为南疆、北疆分别讨论，分析发现：北疆的雨季比南疆早一个月左右，并呈现双峰型特点；50a来，新疆夏季的降水总体是增加的，南疆比北疆明显，1985年是一个明显的气候突变点；新疆夏季降水存在准3a、准5～6a和准10～13a的显著周期，但南疆还存在显著的准20～22a的大尺度振荡周期，北疆则不存在；环流分析表明新疆地区夏季降水异常与500hPa环流配置及南亚高压密切相关。

The spatial and temporal features and circulation characteristics of summer precipitation anomaly in Xinjiang are investigated on the basis of the monthly rainfall data at 160 stations from 1951 to 2000 in China. The whole Xinjiang are divided into the south and north parts according to the complex topography of Xinjiang. Results show that the rainy season in the north began one month earlier than that in the south ,and in addition to May and June there was another rainy period in October and November. The summer precipitation in Xinjiang has on the whole increased in the last 50 years, and the in crease in south was more obvious than that in north. There were quasi-three-year, quasi-five-to-six-year and quasiten-to-thirteen-year periodic oscillations in summer precipitation, and a sudden change in the year of 1985. In addition,the south had another quasi-twenty-to-twenty-two-year periodic oscillation whereas the north had not. The above results indicate that the wet/dry phase of climate in Xinjiang is close related with the 500 hPa height field and the location and intensity of the south asian high.