Observed trends of precipitation amount, frequency, and intensity in China, 1960–2000

Abstract

We examined the spatial and temporal variation in precipitation observed daily at 272 weather stations operated by the China Meteorological Administration from 1960 to 2000. We found that precipitation in China increased by 2% over that period, while the frequency of precipitation events decreased by 10%. Seasonally, precipitation increased in winter and summer but decreased in spring and fall. Regional differences also appeared: Precipitation decreased in the North China Plain and north central China, showed almost no change in southwest China, and increased in China's five other climatic regions. Only the increase in northwest China, however, was statistically significant ( p = 0.05). For China as a whole and its eight climatic regions these changes in precipitation can be attributed mostly to changes in the frequency and intensity of heavy precipitation events. Nationwide, the increased frequency of heavy precipitation events contributed 95% of the total increase of precipitation in that category. At the same time, there were fewer light precipitation events, accounting for 66% of the national reduction in precipitation frequency. In seven of the eight climatic regions, changes in frequency accounted for most of the changes in the amounts of precipitation from heavy precipitation events; changing intensity accounted for a larger share in the southwestern region. The frequency of precipitation has decreased in all seasons and all regions except northwest China. The increasing proportion of precipitation delivered by heavy rainfall events and the decreasing trend of light precipitation events have potentially serious ramifications for flood control and vegetation production, especially for the non‐irrigated croplands in the arid and semiarid areas of China.