中文摘要：

用全国1958--2004年逐日降水资料，分析我国东部地区夏季总降水日数以及不同等级降水日数的年代际变化特征，结果表明，1980--2004年与1958--1979年两个时段相比，我国东部各地区夏季总降水日数和不同等级降水日数具有明显不同的变化特征。东北地区总降水日数和总降水量减少，这主要与小雨日数减少有关。华北地区总雨日数和总降水量也呈减少特征，总雨日数减少是由于各等级雨日数减少引起，且小雨日数减少贡献较大，而总降水量减少却主要是由于暴雨日数的减少引起。长江流域总降水日数和总降水量增加，总雨日数增多主要与中雨以上级别雨日数的增多有关，而总降水量的增加主要与暴雨日数增加有关。华南地区总雨日数和总降水量减少，总雨日数减少主要与小雨日数减少有关，而总降水量减少是由于各等级降水日数减少引起。

英文摘要：

The interannual variations both of total summer rainfall days and rainfall days with different class intervals over eastern China are analyzed by using the daily precipitation data in China during 1958--2004. The results show that the number of total summer rainy days and rainfall days with different rainfall amount over eastern China in the period of 1980--2004 was obviously different from that in the period of 1958--1979. The total rainfall days and total precipitation amount decreased after 1980 in Northeast China, due to the reduction in light rainy days. The total rainfall days and total rainfall amount also decreased after1980 in North China, the former is attributed to the reduction in the rainfall days with every class interval, especially in light rainy days, and the total precipitation amount reduced due to the decrease of the rainstorm days. In the Yangtze River valley region the rainy days and precipitation amount increased after 1980, as the total rainfall days increased with the increase of rain days for moderate rain and heavier, but total precipitation increased mainly because of increase of rainstorm days. In south China the rainfall days and precipitation amount reduced after 1980, the latter is due to fall amount in every rainfall class, while the reduction of the rainy days is associated light rainy days.