Abstract: Based on the summer precipitation data in eastern China during 1880-2006 and at 160 stations in China during 1951-2006, and 500 hPa geopotential height data in the North Hemisphere during 1951-2006, the decadal variation law of summer rain-pattern was explored. The results show that there existed obvious 20-to 40-year period in the eastern monsoon region and the western region, and about 15-year period in the northeastern region of China. Additionally, the main features of geopotential heights at 500 hPa in the Northern Hemisphere for different summer rain-patterns were analyzed. Results show obvious differences of East Asian circulation for four rain-patterns in the eastern monsoon region, and the basically opposite allocation of Eurasia circulation pattern between the two rain-patterns in the western region and the two rain-patterns in the northeastern China.

Key words: China, summer rain-pattern, decadal variation, circulation feature