关键词: 西北地区, 夏季降水, 年际年代际, 气候特征

Abstract: Based on the summer precipitation (from June to August) data in the 119 meteorological stations from 1961 to 2000 in the Northwest China, the average precipitation and its variance, inter-annual and decades distribution characteristics of average precipitation were calculated. The results showed that according to the summer rainfall the Northwestern China could be divided into three basic climatic zones, including North Xinjiang, Mid-west river basin dessert and East monsoon influenced region. The precipitation and its variance in the Mid-west river basin dessert region was lowest and in status of stead drought. The precipitation and its variance in the East monsoon influenced region changed in a wide range with increased drought occurrence. The precipitation in the North Xinjiang region was high and changed not so big as in the East monsoon influenced region. The inter-decades distribution of precipitation in the three zones was different. The changes of precipitation could directly influence the yields of main local crops in drylands.

Key words: Northwest region, Northwest region, Summer precipitation, Inter-annual and-decades, Climate character