基于安康地区近60a的逐日降水和历年最大洪峰流量资料,采用Mann-Kendall检验、百分位阈值、滑动平均、相关性分析以及趋势分析方法,并结合世界气象组织(WMO)提供的降水指数,对安康地区1953-2011年极端降水的时序特征、突变特点以及降水与洪涝灾害的相关性进行了分析。结果表明:近60a来,安康地区年最大日降水量、极端降水日数、极端降水量以及极端降水强度都呈波动上升趋势。其中,年最大日降水量在1974年发生了增多突变,1983年达到显著增多水平;极端降水日数在2002年发生了增多突变,2011年达到显著增多水平;极端降水量和极端降水强度在1997年之后一直呈上升趋势,但没有发生突变现象。1997年后,尤其是进入21世纪以来,安康地区极端降水日数、极端降水量、极端降水强度明显上升,在总降水量减少的情况下,降水时间分布更加不均匀,降水集中度增加,极端降水事件增多。因此,必需高度重视汉江上游安康地区潜在的洪涝灾害,增强应对和抵御灾害的能力,确保人民生命财产安全和南水北调工程的顺利实施。
Based on the daily precipitations and the annual peak discharge of Ankang region in recent 60 years, this paper analyzed the timing characteristics, the mutation characteristics of the extreme precipitation and the cor- relations between the precipitation and the flood disasters from 1953 to 2011 in Ankang region, using Mann-Kendall test, percentile threshold, moving average, correlation analysis and trend analysis combined with the precipitation indexes provided by WMO. The results showed that the maximum daily precipitation, the extreme precipitation in- tensity, the number of the extreme precipitation days and the amount of the extreme precipitations in Ankang region all presented waving rising trends in the past 60 years. The mutation of the maximum daily precipitation appeared in 1974 and significantly increased in 1983 ; the mutation of the number of the extreme precipitation days appeared in 2002 and significantly increased in 2011 ; the amount of the extreme precipitations and the extreme precipitation in- tensity both presented rising trends since 1997 but no mutation occurred. Since 1997, particularly from the begin- ning of the 20th century, the number of the extreme precipitation days, the amount of the extreme precipitations and the extreme precipitation intensity apparently and significantly increased in Ankang region while the total pre- cipitation were decreasing. Therefore, the potential flooding disasters have called for more attentions in the upper reach of the Hanjiang river in Ankang area to build up the ability to ensure the safety of the people's life and prop- erty and the security of the South-to-North Water Diversion Project.