Abstract:

Using daily p recip itation data of 41 meteorological stations in CentralNorth China from 1961 to 2005 and the extreme p recip itation indices developed byWMO /CCL and CL IVAR, the temporal and spatial characteristics of extreme p recip itation events change was analyzed. Results show that the annual average maximum daily p recip itation p resented a decreasing trend in centralNorth China,but the average heavy and extreme rainfall days changed indistinctively; the days and intensity of heavy rainfall increased obviously in the middle and late 1990 s’; there was a significant drop in rainfall days, especially in the south and southeast region, but no significant change in rainfall intensity. These imp ly that the p roportion of the extreme p recip itation events in the total rainfall days increased,and the p roportion of extreme p recip itation amount in the total annual p recip itation might increase also in the period 1961 - 2005 in the researchregion.

Key words: central north China, extreme p recip itation, heavy rainfall days, rainstorm days

摘要：

利用华北中部41个气象台站1961～2005年逐日降水资料,采用通用的极端气候指数,分析了近45 a来华北中部极端降水事件频率变化的时空特征。结果表明:华北中部平均年最大日降水量呈下降趋势,南部平原地区一般减少,北部山地区域多有增加,降水日数有较明显减少,强降水日数和暴雨日数变化趋势不明显,降水日数的减少主要是中、小雨(雪)日数减少造成的。暴雨日数和强度在20世纪90年代中后期显著增加。华北中部强降水日数和暴雨日数在降水日数中的比重有增大趋势,强降水量和暴雨降水量在总降水量中的比重可能也增加了。这种相对增加趋势主要发生在20世纪90年代中期以后。

关键词: 华北中部, 极端降水, 强降水日数, 暴雨日数