关键词: 东亚季风强度指数, 降水距平一致率, 陕西, 大气环流

Abstract: By using the NCEP/NCAR reanalysis data and monthly precipitation data in Shaanxi Province from 1979 to 2011，the East-Asian summer monsoon intensity index and precipitation anomaly consistent rate were calculated，the relationships between the monsoon intensity indexes and precipitation were investigated using statistical correlation analysis method. The atmospheric circulation characteristics of Shannxi rainy year and drought year were discussed with the strong （weak） East-Asian summer monsoon. The result showed that：the strong East-Asian summer monsoon meant more rain in Shaanxi，and plenty rainfall in North Shaanxi and Guanzhong，while the weak East- Asian summer monsoon meant less rain，and significant less in the north of Northern Shaanxi. The more rain had the characteristics of a positive-negative-positive anomalous distribution from west to east in high latitudes in Europe and Asia，general circulation of the stronger ridge at Ural Mountain，deeper trough from Lake Baikal to the Balkhash，stronger west Pacific subtropical high，the south airflow prevailing the east side of Tibetan plateau，meanwhile the weak north airflow prevailing in North China. There was cyclonic shear of anomaly wind fields in eastern part of northwest China lead to more rain. While the general circulation characteristics of less rain were negative-positive- negative anomalous distribution from west to east in high latitudes in Europe and Asia，stronger long wave ridge at Central-Asian，weaker and position by east of western Pacific subtropical high. It was hot and dry weather in Shaanxi controlled by northwest flow of Central-Asian ridge. But it was wet day when East-Asian summer monsoon was weak，East Asia mid-latitude was prevailing straight westerly flow，westerly jet located at 40°N，location of the western Pacific subtropical high was to the south and west as compared with the normal，Tibetan plateau potential height was lower than normal and more short wave trough or low-pressure system. The westerlies system and low pressure system of plateau east shift had impact on the summer more rain in Shaanxi Province.

Key words: East-Asian summer monsoon, precipitation anomaly consistent rate, Shaanxi Province, the atmospheric circulation