近62年来汉中市极端降水变化研究

Change in extreme precipitation during past 62 years in Hanzhong

【目的】对汉中市极端降水事件的变化趋势进行研究,为汉中地区防洪减灾和水资源调控决策提供参考依据。【方法】利用1951-2012年的汉中市逐日降水资料,采用百分位阈值划分极端降水事件,并通过滑动平均、Mann-Kendall检验、趋势分析等方法,对汉中市极端降水事件的变化趋势进行研究。【结果】近62年来,汉中市年极端降水量、年极端降水日数及年极端降水强度以年代际尺度波动变化,但总体略呈下降趋势,且年极端降水量的下降速率为-0.5mm/年。但在1987年之后,各项极端降水指标均呈明显增加趋势,年极端降水量和年极端降水日数呈显著的线性增加趋势,年极端降水量增加速率达7.52mm/年。2006-2008年,汉中市年最大日降水量、年极端降水量、年极端降水强度呈显著增多增强趋势。【结论】进入21世纪后,汉中市极端降水事件引发的自然灾害呈增加趋势,应加强调控及防治能力,预防洪涝灾害的发生。

【Objective】The tendency of extreme precipitation in Hanzhong was studied to help local flood control,disaster mitigation and water resources regulation.【Method】Based on the daily precipitation in Hanzhong from 1951 to 2012,the changes of extreme precipitation events were investigated using percentile threshold to group extreme precipitation events and through methods of moving average,MannKendall test,and trend analysis.【Result】In the past 62 years,the extreme precipitation and extreme precipitation days in Hanzhong fluctuated with a downward trend of-0.5mm/year.But after 1987,various indexes of extreme precipitation showed increasing trends and annual extreme precipitation and extreme precipitation days increased significantly.The annual extreme precipitation increased linearly with the rate of 7.52 mm/year.During 2006-2008,annual maximum daily precipitation,annual extreme precipitation and extreme precipitation intensity in Hanzhong increased significantly.【Conclusion】In the 21 century,the natural disaster in Hanzhong showed increasing tendency due to increase of extreme precipitation events.Thus,regulation and measures should be taken to prevent disaster.