Abstract: Based on a daily precipitation dataset of 521 meteorological stations in China, trends of regional average precipitation amounts, precipitation days and daily precipitation intensities of the 9 different precipitation classes, rangingfrom 0.1-4.9 ,5-9.9 , 10- 16. 9 ,17-24. 9 ,25-37.9 ,38- 49. 9 ,50-74. 9 ,75-99.9 mmto over 100 mm, were studied for the period of 1961-2000. The results revealed that,the trends of the lightest precipitation amounts were caused bythe changes of precipitation days, while the changes of the heaviest precipitation amounts were mainly dominated by the precipitation intensity. The analysis on precipitation frequency and the proportion of precipitation amount of each precipitation class showed that, in spite of the decreasing trend in North China and Sichuan Basin, the precipitation frequencies andthe proportions of precipitation amounts in other regions went upward significantly, indicating an increasing contribution of the heavier precipitation to the total precipitation amount.

Key words: precipitation, intensity, trend

摘要： 利用中国521个地面气象观测站1961?2000年的日降水资料, 分析了0.1 ～4.9 ,5 ～9.9 ,10 ～16.9 ,17 ～24.9, 25 ～37.9 ,38 ～49.9 ,50 ～74.9 ,75 ～99.9 mm 和大于100 mm共9个不同量级降水的降水量、降水日数和日平均降水强度的变化趋势。结果表明, 对各区域最小降水量级(0.1～4.9mm)的降水, 其降水日数的变化起着主导的作用,而对于各区域最大降水量级的降水, 降水强度的变化起着决定性的作用。降水频率和降水量百分比的分析显示,除华北和四川盆地两个区域外, 其他地区强降水出现的频率和降水量百分比都趋于增加, 强降水对总降水量的贡献呈现增大的趋势。

关键词: 降水, 强度, 趋势