Hourly summer precipitation data recorded at 21 stations during 1961-2004 in the Haihe River Basin in North China were an alyzed. The results show that the precipitation frequency and amount and the morning peak mainl...Hourly summer precipitation data recorded at 21 stations during 1961-2004 in the Haihe River Basin in North China were an alyzed. The results show that the precipitation frequency and amount and the morning peak mainly relating to longduratiol rainfall events decreased during this period, whereas the normalized afternoon peak mainly relating to short-duration event： increased, which may suggest that the proportion of short-duration rainfall has increased as the total summer rainfall has de creased. For short-duration events, the mean intensity and peak intensity increased at most stations and the time to peak inten sity decreased, which may be attributable to the higher thermal contrast between the warmer lower surface and cooler uppe level. In the case of long-duration events, the total amount was significantly correlated with the East Asian summer monsool index for the period 1961-2001 （correlation coefficient of 0.63）. Although the total amount of rainfall in long-duration event： decreased in the basin, the mean intensity and peak intensity, as well as the extreme hourly precipitation, increased in the western basin and decreased in the eastern basin.展开更多
基金supported by the National Basic Research Program of China (Grant No. 2006CB403404)the National Key Technology R&D Program of China (Grant No. 2007 BAC29B04)the National Science Foundation Program for Post-doctoral Scientists of China (Grant No. 20080440343)
文摘Hourly summer precipitation data recorded at 21 stations during 1961-2004 in the Haihe River Basin in North China were an alyzed. The results show that the precipitation frequency and amount and the morning peak mainly relating to longduratiol rainfall events decreased during this period, whereas the normalized afternoon peak mainly relating to short-duration event： increased, which may suggest that the proportion of short-duration rainfall has increased as the total summer rainfall has de creased. For short-duration events, the mean intensity and peak intensity increased at most stations and the time to peak inten sity decreased, which may be attributable to the higher thermal contrast between the warmer lower surface and cooler uppe level. In the case of long-duration events, the total amount was significantly correlated with the East Asian summer monsool index for the period 1961-2001 （correlation coefficient of 0.63）. Although the total amount of rainfall in long-duration event： decreased in the basin, the mean intensity and peak intensity, as well as the extreme hourly precipitation, increased in the western basin and decreased in the eastern basin.
