摘要
为探究大通河上中游天然水文节律受气候变化的影响,选择该区域气候增温迅速的突变时间1997年为分界点,基于水文指标及其变化范围评价法(IHA-RVA法),共选取32个指标对尕大滩/青石嘴水文站1960—1996年、1997—2016年2个时段的径流过程进行分析,并应用主成分分析法去除冗余指标,优选8个代表性指标计算整体的水文改变度。结果表明:1997年前后水文指标变化较明显的有汛前5月份流量减少24.1%,枯季月份流量(1—3、11和12月份)、年多日最小流量和基流指数显著增大,多项指标增幅大于80%,发生高度改变;低脉冲次数和历时分别减少50%和85.7%,高脉冲次数减少2次,高脉冲历时增加21.7%。优选的8个代表性指标计算出的大通河上中游段的整体水文改变度为43%,表明在气候变化影响下上中游段总的改变程度达到中等程度,如此大的改变也与大通河源头区的含水层分布有关。
River hydrological rhythm reflects the dynamic changes in natural characteristics of water flow and is the key element of the river ecosystem.Recently,the rapid warming of the Qinghai Tibet Plateau has changed the hydrological rhythm of rivers to a certain extent.There is a national aquatic germplasm reserve in Datong River,and the Qilian Mountain area where it is located has an increase of 2.3℃cumulative temperature.Therefore,exploring the changes in hydrological rhythm in the upper and middle reaches of Datong River under climate change has great significance and can play a supporting role in the ecological protection and water resources management of Datong River.There is evidence of the temperature rise rate on the Qinghai Tibet Plateau in the late 1990s.The data of meteorological stations around the upper and middle reaches of Datong River show that the average annual temperature increase rate after 1997 is 10 times before 1997.With the rapid increase in temperature,the relationship between frozen soil,glaciers,and rainfall runoff in Datong River basin has significantly changed.Based on the IHARVA method,the abrupt change time of rapid climate warming in the region in 1997 was selected as the dividing point.A total of 32 indicators were selected to analyze the runoff process in 1960-1996 and 1997-2016 for Gadatan/Qingshizui hydrological station.The principal component analysis method was used to remove redundant indicators,and 8 representative indicators were selected to calculate the overall hydrological change.The results show that:(1)April and October are the months of ice melting and freezing,which are directly affected by climate change.The change degree of median flow is 26.3%and 15.8%,respectively,belonging to slight change.The annual minimum flow of 30 d is representative of the annual minimum flow(1 d,3 d,7 d,and 90 d)and the median flow in dry season months.The change is significant,and the change degree reaches 100%.(2)The annual average maximum flow in 7 d is representative of the annual average multi-day maximum flow(1 d,3 d,30 d,and 90 d).The median value of the maximum flow in 7 d,and is unchanged,but the probability of falling increases between 25%and 75%,and the degree of change reaches 47%,which is a moderate change.The occurrence time of the annual maximum value,i.e.the occurrence time of the annual extreme flow,is averagely advanced by 7 to 9 d,which is a low change.(3)The number of low pulses is equivalent to the number of flow processes below 75%of the frequency,which is reduced from 2 to 1,and the duration is reduced from 49 d to 7 d.The change degree of the number and duration of low pulses is 29.8%and 50.1%,belonging to low and moderate change.The duration of a high pulse is equivalent to the duration of the flow process which is 25%higher than the frequency,increasing from an average of 5.8 d to 7 d,and the degree of change is 24.1%,which belongs to a low degree of change.The rising rate represents the change rate of flow change.The change rate slows down and low-degree changes occur.(4)The overall hydrological change degree of the upper and middle reaches of Datong River is 43%,indicating that the overall change degree of the upper and middle reaches under the influence of climate change has reached a medium level.With the expansion of the melting area,the transformation of water on the frozen layer and water in the frozen layer intensifies the change in the runoff process.
作者
康泽璇
王芳
刘扬
左俊康
KANG Zexuan;WANG Fang;LIU Yang;ZUO Junkang(State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100038,China)
出处
《南水北调与水利科技（中英文）》
CAS
北大核心
2022年第6期1065-1075,共11页
South-to-North Water Transfers and Water Science & Technology
基金
水利部水利前期工作投资计划项目(WR0157B162018)。
关键词
大通河
气候变化
水文节律
IHA
主成分分析法
水文改变度
Datong River
climate change
hydrological rhythm
IHA
principal component analysis
hydrological change degree
