近60年渭河流域极端降水和洪水演变特征  

Evolution Characteristics of Extreme Precipitation and Floodin the Weihe River Basin of China over Last 60 Years

作　　者：刘吉峰[1] 靳莉君[1] 张永生 LIU Jifeng;JIN Lijun;ZHANG Yongsheng(Hydrological Bureau of Yellow River Conservancy Commission,Zhengzhou 450004,China)

机构地区：[1]黄河水利委员会水文局,郑州450004

出　　处：《山地学报》2023年第2期192-203,共12页Mountain Research

基　　金：国家重点研发计划项目专题(2021YFC3201104-02)~。

摘　　要：渭河流域地处中国西北地区东部,是气候敏感区和生态环境脆弱区,极端降水事件往往引发洪水、泥石流等灾害。现有研究主要集中在降水引发的流域径流变化,而极端降水和洪水变化规律有待挖掘。本文基于1961—2021年气象水文资料,选用8个极端降水指数、4个代表水文站年最大洪峰流量,采用百分位阈值法、Kriging空间插值法、线性回归法、滑动平均法、小波分析法,分析了渭河流域极端降水和洪水时空演变特征、周期特征以及2021年极端降水和洪水特性。结果表明:(1)近60年渭河流域极端降水总量和暴雨频次显著增加的同时,极端降水强度亦有所增强,而弱降水事件减少。极端洪水整体呈不显著减少趋势。极端降水和洪水均在2000年以后显著增加,特别是极端降水总量和暴雨频次较多年均值偏多12%~22%,并且各极端降水指数极大值均出现在2000年以后。(2)极端降水和洪水年内分布不均,前者主要集中在7月和8月,后者除“七下八上”期外,9月也是多发期。(3)各极端降水指数均呈现由上游向下游递增的分布,中游南部极端降水普遍强于北部。流域内大部分站点极端降水指数呈增加趋势,显著增加地区位于中游周至—临潼区间以及长武—宁县。(4)极端降水和洪水存在多个周期变化特征,且极端洪水周期年代际特征显著。(5)2021年渭河流域极端降水强度、大雨以上降雨日数均为近61年来之最,华县站出现2012年以来最大洪水过程,咸阳站出现1935年有实测资料以来9月份同期最大洪水。研究结果可为渭河流域水旱灾害防御以及治理规划提供参考依据。The Weihe River basin lies in the east of northwest China.It is a climate-sensitive and a fragile ecological environment area.Extreme precipitations often cause floods,debris flows and other disasters in the basin.Previous research mainly concerned about the regional runoff change caused by rainfall,but the change law of extreme precipitation and flood remained unknown.In this study,it collected meteorological and hydrological data of 1961-2021,and eight extreme precipitation indices and annual maximum flood peak flow records at four representative hydrological stations were selected for statistical analysis.The method of percentile threshold,Kriging spatial interpolation,linear regression,and moving average and wavelet analysis was used to analyze the evolution pattern of extreme precipitation and flood in the Weihe River basin of China,the periodic change,and the extremity of precipitation and flooding in 2021.The results show that:(1)In the past 60 years,while the total amount of extreme precipitation and the frequency of rainstorm increased significantly,the intensity of extreme precipitation also increased,but the weak precipitation events decreased in the Weihe River basin.Extreme floods generally showed a non-significant reduction trend.Both extreme precipitation and flooding increased significantly after 2000.In particular,the total amount of extreme precipitation and the rainstorm frequency were 12%~22%higher than those of the annual average,and the maximum value of each extreme precipitation index all appeared after 2000.(2)The distribution of extreme precipitation and flood was not uniform within a year.The former was mainly concentrated in July and August,while the latter was also frequent in September except for a period of late July to early August.(3)Each extreme precipitation index showed an increasing distribution from upstream to downstream,and the extreme precipitation in the south of the middle reaches of the basin was generally stronger than that in the north.The extreme precipitation index o

关 键 词：极端降水 年最大洪峰流量 趋势分析 小波分析 时空变化 渭河流域 

分 类 号：P426[天文地球—大气科学及气象学]