近50a黄河三角洲极端降水事件特征研究

Research on Characteristics of Extreme Precipitation Events in the Yellow River Delta over the Past 50 Years

利用黄河三角洲地区5个气象站1961—2007年逐日实测降水资料,采用适合当地实际状况的通用极端气候指数,分析近50 a来黄河三角洲地区极端降水事件变化特征。结果表明:黄河三角洲地区的逐年最大日降水量、强降水日数、强降水强度、暴雨日数和暴雨强度等5个指数均呈现逐步下降趋势;从年代际特征来看,20世纪60年代至今大约经历了3个"先下降后上升"的变化过程;极端降水量与年降水总量存在较好的相关性,相关系数在0.75以上;最大日降水量、强降水日数和暴雨强度3个指数在70年代末和80年代初发生突变,其特征与华北中部地区基本保持一致。

Using measured daily precipitation data of 5 meteorological stations in the Yellow River delta from 1961 to 2007 and the general extreme precipitation indices suitable for the actual local conditions, the temporal characteristics of extreme precipitation events change was analyzed. The resuits show that the annual maximum daily precipitation, heavy precipitation days and intensity, rainstorm days and intensity present a decreasing trend in the area. From the 1960s, the extreme precipitation experiences about 3 change processes which falls first and rises later. The extreme precipitation has a good correlation with the total annual precipitation, and the correlation coefficient is more than 0.75. The annual maximum daily precipitation ,heavy precipitation days and rainstorm intensity change abruptly at the end of 1970s and the beginning of 1980s ,which is similar to the change characteristic in central north China.