Quantitative assessment of the impact of climate variability and human activities on runoff plays a pivotal role in water resource management and maintaining ecosystem integrity.This study considered six sub-basins in...Quantitative assessment of the impact of climate variability and human activities on runoff plays a pivotal role in water resource management and maintaining ecosystem integrity.This study considered six sub-basins in the upper reaches of the Yangtze River basin,China,to reveal the trend of the runoff evolution and clarify the driving factors of the changes during 1956–2020.Linear regression,Mann-Kendall test,and sliding t-test were used to study the trend of the hydrometeorological elements,while cumulative distance level and ordered clustering methods were applied to identify mutation points.The contributions of climate change and human disturbance to runoff changes were quantitatively assessed using three methods,i.e.,the rainfall-runoff relationship method,slope variation method,and variable infiltration capacity(Budyko)hypothesis method.Then,the availability and stability of the three methods were compared.The results showed that the runoff in the upper reaches of the Yangtze River basin exhibited a decreasing trend from 1956 to 2020,with an abrupt change in 1985.For attribution analysis,the runoff series could be divided into two phases,i.e.,1961–1985(baseline period)and 1986–2020(changing period);and it was found that the rainfall-runoff relationship method with precipitation as the representative of climate factors had limited usability compared with the other two methods,while the slope variation and Budyko hypothesis methods had highly consistent results.Different factors showed different effects in the sub-basins of the upper reaches of the Yangtze River basin.Moreover,human disturbance was the main factor that contributed to the runoff changes,accounting for 53.0%–82.0%;and the contribution of climate factors to the runoff change was 17.0%–47.0%,making it the secondary factor,in which precipitation was the most representative climate factor.These results provide insights into how climate and anthropogenic changes synergistically influence the runoff of the upper reaches of the Yangtze River basin.展开更多
River runoff in the Arctic and the Tibetan Plateau(TP) change significantly in recent decades. However, the mechanisms of the physical processes of permafrost river runoff change remain uncertain across large scale. T...River runoff in the Arctic and the Tibetan Plateau(TP) change significantly in recent decades. However, the mechanisms of the physical processes of permafrost river runoff change remain uncertain across large scale. This study investigated the mainstreams and tributaries of main Arctic and TP rivers dominated by permafrost and assessed the linkage between hydrological regime change and permafrost. The results show that the effects of permafrost on river runoff are highly dependent on the permafrost coverage of a watershed. For the past decades, the majority of the Arctic and TP basins showed increased discharge, while all of the studied basins showed increased baseflow, with faster increasing speed than total discharge.Both total discharge and baseflow annual change rate(ΔQ and ΔBF) increased with permafrost coverage, indicating the increments of streamflow are enhanced with high permafrost coverage. Meanwhile, the annual change of precipitation showed weak connection with total discharge and baseflow change. The high permafrost coverage basins showed high annual maximum/minimum discharge ratio(Qmax/Qmin), while the Qmax/Qminchanged slightly in low permafrost cover basins. Our results highlight the importance of permafrost coverage on streamflow regime change for permafrost basins across the northern hemisphere. Due to these linkage between permafrost extent and runoff regime change and the increasing changes of permafrost, more attention should be paid to the change of hydrological processes in permafrost-underlain basins.展开更多
Quantification of the impacts of environmental changes on runoff in the transitional area from the Tibetan Plateau to the Loess Plateau is of critical importance for regional water resources management.Trends and abru...Quantification of the impacts of environmental changes on runoff in the transitional area from the Tibetan Plateau to the Loess Plateau is of critical importance for regional water resources management.Trends and abrupt change points of the hydro-climatic variables in the Tao River Basin were investigated during 1956-2015.It also quantitatively separates the impacts of climate change and human activities on runoff change in the Tao River by using RCC-WBM model.Results indicate that temperature presented a significant rising trend(0.2℃per decade)while precipitation exhibited an insignificant decreasing trend(3.8 mm per decade)during 1956-2015.Recorded runoff in the Tao River decreased significantly with a magnitude of-13.7 mm per decade and abrupt changes in 1968 and 1986 were identified.Relative to the baseline period(1956-1968),runoff in the two anthropogenic disturbed periods of 1969-1986 and 1987-2015 decreased by 27.8 mm and 76.5 mm,respectively,which can be attributed to human activities(accounting for 69%)and climate change(accounting for 31%).Human activities are the principal drivers of runoff reduction in the Tao River Basin.However,the absolute influences on runoff reductions by the both drivers tend to increase,from 7.7 mm in 1969-1986 to 24.4 mm in 1987-2015 by climate change and from 20.2 mm to 52.2 mm by human activities.展开更多
Based on the 58 years monthly flow data (from 1956 to 2013) editing by Jingle hydrological station of Fen River and Shangjinyou station, data resources are used to analyze the annual and inter-annual changes from spat...Based on the 58 years monthly flow data (from 1956 to 2013) editing by Jingle hydrological station of Fen River and Shangjinyou station, data resources are used to analyze the annual and inter-annual changes from spatial and temporal scale by statistical methods, mainly annual spatial and temporal distribution, trend of inter-annual changes, cycle and mutation changes. The reasons of runoff into reservoir changes are deeply analyzed by annual precipitation data of catchments above Fenhe Reservoir 1956 to 2013 and the land and water reservation methods which are implemented recently. It shows that there is a significant decrease of the inter-annual run-off with main and second cycle periods, 23a and 13a respectively. Furthermore, it exists mutation point between 1970 and 1971 through runoff series. As for further analysis of the causes of Fenhe Reservoir runoff changes, it illustrates that the change of precipitation is the main reason the facilitate runoff changes. Also, the land and water reservation methods which are implemented in upstream of Fenhe Reservoir increase water storage capacity of soil, showing it non-ignorable effect to runoff changes.展开更多
Significant changes in water cycle elements/processes have created serious challenges to regional sustainability and high-quality development in the Yellow River Basin in China.It is necessary to investigate the impac...Significant changes in water cycle elements/processes have created serious challenges to regional sustainability and high-quality development in the Yellow River Basin in China.It is necessary to investigate the impacts of climate change and human activities on hydrological evolution and disaster risk from a holistic perspective of the basin.This study developed initiatives to clarify the mechanisms of hydrological evolution in the human-influenced Yellow River Basin.The proposed research method includes:(1)a tool to simulate multiple factors and a multi-scale water cycle using a grid-based spatiotemporal coupling approach,and(2)a new algorithm to separate the responses of the water cycle to climate change and human impacts,and de-couple the eco-environmental effects using artificial intelligence techniques.With this research framework,key breakthroughs are expected to be made in the understanding of the impacts of land cover change on the water cycle and blue/green water redirection.The outcomes of this research project are expected to provide theoretical support for ecological protection and water governance in the basin.展开更多
A clear understanding of the changes of water resources under the background of environmental changes is of great significance for scientific management and utilization of water resources in China.This study systemati...A clear understanding of the changes of water resources under the background of environmental changes is of great significance for scientific management and utilization of water resources in China.This study systematically analyzed the spatialetemporal variations of surface water resources in China since 2000.Water vulnerability in current(2010s)and its trends from 2000 to late-2010s in different regions of China were also summarized.In addition,the correspondingly adaptive measures to counter regional risks to water resources were proposed.We concluded that the runoff of major rivers had been decreasing in eastern China and increasing in western China during 2000-2018.In the arid area of Northwest China,the alpine runoff has shown an overall upward trend since the late-1990s/early-2000s,with a 10%-25% increase caused by the increase of glacial meltwater and precipitation.While the runoff of each hydrological station in the 2000s-2010s was 34.7% lower than that in the 1950se2010s on average.The increases in precipitation and glacial meltwater with global warming caused a rapid expansion of lakes in the Qinghai-Tibet Plateau and Xinjiang,thus leading to an increase in total area and water quantity of lakes in China from 1995 to 2015.The mean contribution rates of climate change and human activity to runoff change in river basins of China were 53.5% and 46.5%,respectively,during the period of 2000-2010s.The driving factor of runoff change in many river basins has gradually changed from climate change(1950s-2000)to human activity(2000-2018).During 2000-2018,the contributions of human activities to runoff change were 50%-80% in major rivers of eastern China.The vulnerability in most areas of Northwest China and North China is generally high,with the vulnerability index greater than 0.6.Comparatively,in Northeast,East,South,and Central China,it is lower or not vulnerable.In Southwest China,the vulnerability varies greatly with Yunnan and Sichuan relatively low while Chongqing and Guizhou relatively high.The precipitation increase,the application of water-saving technology,the establishment of flood control and drought relief engineering facilities,and the introduction of relevant policies and measures have helped to gradually reduce the vulnerability of water resources in most areas of North and Northwest China(except Xinjiang)from 2000 to 2010s.Water vulnerability has been increasing in southern China,caused by climate change and the development of industry and agriculture,which increases water resource exposure since 2000.Based on the typical risk factors and vulnerability characteristics of water resources in different regions,this study proposed some targeted adaptive measures correspondingly so as to scientifically deal with the problems of surface water resources in China.展开更多
基金supported by the National Natural Science Foundation of China(52009140).
文摘Quantitative assessment of the impact of climate variability and human activities on runoff plays a pivotal role in water resource management and maintaining ecosystem integrity.This study considered six sub-basins in the upper reaches of the Yangtze River basin,China,to reveal the trend of the runoff evolution and clarify the driving factors of the changes during 1956–2020.Linear regression,Mann-Kendall test,and sliding t-test were used to study the trend of the hydrometeorological elements,while cumulative distance level and ordered clustering methods were applied to identify mutation points.The contributions of climate change and human disturbance to runoff changes were quantitatively assessed using three methods,i.e.,the rainfall-runoff relationship method,slope variation method,and variable infiltration capacity(Budyko)hypothesis method.Then,the availability and stability of the three methods were compared.The results showed that the runoff in the upper reaches of the Yangtze River basin exhibited a decreasing trend from 1956 to 2020,with an abrupt change in 1985.For attribution analysis,the runoff series could be divided into two phases,i.e.,1961–1985(baseline period)and 1986–2020(changing period);and it was found that the rainfall-runoff relationship method with precipitation as the representative of climate factors had limited usability compared with the other two methods,while the slope variation and Budyko hypothesis methods had highly consistent results.Different factors showed different effects in the sub-basins of the upper reaches of the Yangtze River basin.Moreover,human disturbance was the main factor that contributed to the runoff changes,accounting for 53.0%–82.0%;and the contribution of climate factors to the runoff change was 17.0%–47.0%,making it the secondary factor,in which precipitation was the most representative climate factor.These results provide insights into how climate and anthropogenic changes synergistically influence the runoff of the upper reaches of the Yangtze River basin.
基金supported by the Major Research Plan of the National Natural Science Foundation of China(Grant No.91547203)the National Natural Science Foundation of China(Grant No.41890821)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA20050102)
文摘River runoff in the Arctic and the Tibetan Plateau(TP) change significantly in recent decades. However, the mechanisms of the physical processes of permafrost river runoff change remain uncertain across large scale. This study investigated the mainstreams and tributaries of main Arctic and TP rivers dominated by permafrost and assessed the linkage between hydrological regime change and permafrost. The results show that the effects of permafrost on river runoff are highly dependent on the permafrost coverage of a watershed. For the past decades, the majority of the Arctic and TP basins showed increased discharge, while all of the studied basins showed increased baseflow, with faster increasing speed than total discharge.Both total discharge and baseflow annual change rate(ΔQ and ΔBF) increased with permafrost coverage, indicating the increments of streamflow are enhanced with high permafrost coverage. Meanwhile, the annual change of precipitation showed weak connection with total discharge and baseflow change. The high permafrost coverage basins showed high annual maximum/minimum discharge ratio(Qmax/Qmin), while the Qmax/Qminchanged slightly in low permafrost cover basins. Our results highlight the importance of permafrost coverage on streamflow regime change for permafrost basins across the northern hemisphere. Due to these linkage between permafrost extent and runoff regime change and the increasing changes of permafrost, more attention should be paid to the change of hydrological processes in permafrost-underlain basins.
基金the National Key Research and Development Programs of China(2016YFA0601501)the National Natural Science Foundation of China(41830863,51879162,41601025)the Belt and Road Fund on Water and Sustainability of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering(2019).
文摘Quantification of the impacts of environmental changes on runoff in the transitional area from the Tibetan Plateau to the Loess Plateau is of critical importance for regional water resources management.Trends and abrupt change points of the hydro-climatic variables in the Tao River Basin were investigated during 1956-2015.It also quantitatively separates the impacts of climate change and human activities on runoff change in the Tao River by using RCC-WBM model.Results indicate that temperature presented a significant rising trend(0.2℃per decade)while precipitation exhibited an insignificant decreasing trend(3.8 mm per decade)during 1956-2015.Recorded runoff in the Tao River decreased significantly with a magnitude of-13.7 mm per decade and abrupt changes in 1968 and 1986 were identified.Relative to the baseline period(1956-1968),runoff in the two anthropogenic disturbed periods of 1969-1986 and 1987-2015 decreased by 27.8 mm and 76.5 mm,respectively,which can be attributed to human activities(accounting for 69%)and climate change(accounting for 31%).Human activities are the principal drivers of runoff reduction in the Tao River Basin.However,the absolute influences on runoff reductions by the both drivers tend to increase,from 7.7 mm in 1969-1986 to 24.4 mm in 1987-2015 by climate change and from 20.2 mm to 52.2 mm by human activities.
文摘Based on the 58 years monthly flow data (from 1956 to 2013) editing by Jingle hydrological station of Fen River and Shangjinyou station, data resources are used to analyze the annual and inter-annual changes from spatial and temporal scale by statistical methods, mainly annual spatial and temporal distribution, trend of inter-annual changes, cycle and mutation changes. The reasons of runoff into reservoir changes are deeply analyzed by annual precipitation data of catchments above Fenhe Reservoir 1956 to 2013 and the land and water reservation methods which are implemented recently. It shows that there is a significant decrease of the inter-annual run-off with main and second cycle periods, 23a and 13a respectively. Furthermore, it exists mutation point between 1970 and 1971 through runoff series. As for further analysis of the causes of Fenhe Reservoir runoff changes, it illustrates that the change of precipitation is the main reason the facilitate runoff changes. Also, the land and water reservation methods which are implemented in upstream of Fenhe Reservoir increase water storage capacity of soil, showing it non-ignorable effect to runoff changes.
基金supported by the National Natural Science Foundation of China(Grant No.U2243203),the Fundamental Research Funds for the Central Universities(Grants No.B200204029 and B220201011),and the Natural Science Foundation of Jiangsu Province(Grant No.BK20210368).
文摘Significant changes in water cycle elements/processes have created serious challenges to regional sustainability and high-quality development in the Yellow River Basin in China.It is necessary to investigate the impacts of climate change and human activities on hydrological evolution and disaster risk from a holistic perspective of the basin.This study developed initiatives to clarify the mechanisms of hydrological evolution in the human-influenced Yellow River Basin.The proposed research method includes:(1)a tool to simulate multiple factors and a multi-scale water cycle using a grid-based spatiotemporal coupling approach,and(2)a new algorithm to separate the responses of the water cycle to climate change and human impacts,and de-couple the eco-environmental effects using artificial intelligence techniques.With this research framework,key breakthroughs are expected to be made in the understanding of the impacts of land cover change on the water cycle and blue/green water redirection.The outcomes of this research project are expected to provide theoretical support for ecological protection and water governance in the basin.
基金supported by the National Natural Science Foundation of China,China(41877156,41730751,and 41771040)the Chinese Academy of Sciences STS Project(KFJ-STS-ZDTP-052)+1 种基金the Science and Technology Program of Gansu Province,China(20JR5RA545)the Youth Talent Project of Northwest Institute of Eco-Environmental Resources,Chinese Academy of Sciences(FEYS2019016).
文摘A clear understanding of the changes of water resources under the background of environmental changes is of great significance for scientific management and utilization of water resources in China.This study systematically analyzed the spatialetemporal variations of surface water resources in China since 2000.Water vulnerability in current(2010s)and its trends from 2000 to late-2010s in different regions of China were also summarized.In addition,the correspondingly adaptive measures to counter regional risks to water resources were proposed.We concluded that the runoff of major rivers had been decreasing in eastern China and increasing in western China during 2000-2018.In the arid area of Northwest China,the alpine runoff has shown an overall upward trend since the late-1990s/early-2000s,with a 10%-25% increase caused by the increase of glacial meltwater and precipitation.While the runoff of each hydrological station in the 2000s-2010s was 34.7% lower than that in the 1950se2010s on average.The increases in precipitation and glacial meltwater with global warming caused a rapid expansion of lakes in the Qinghai-Tibet Plateau and Xinjiang,thus leading to an increase in total area and water quantity of lakes in China from 1995 to 2015.The mean contribution rates of climate change and human activity to runoff change in river basins of China were 53.5% and 46.5%,respectively,during the period of 2000-2010s.The driving factor of runoff change in many river basins has gradually changed from climate change(1950s-2000)to human activity(2000-2018).During 2000-2018,the contributions of human activities to runoff change were 50%-80% in major rivers of eastern China.The vulnerability in most areas of Northwest China and North China is generally high,with the vulnerability index greater than 0.6.Comparatively,in Northeast,East,South,and Central China,it is lower or not vulnerable.In Southwest China,the vulnerability varies greatly with Yunnan and Sichuan relatively low while Chongqing and Guizhou relatively high.The precipitation increase,the application of water-saving technology,the establishment of flood control and drought relief engineering facilities,and the introduction of relevant policies and measures have helped to gradually reduce the vulnerability of water resources in most areas of North and Northwest China(except Xinjiang)from 2000 to 2010s.Water vulnerability has been increasing in southern China,caused by climate change and the development of industry and agriculture,which increases water resource exposure since 2000.Based on the typical risk factors and vulnerability characteristics of water resources in different regions,this study proposed some targeted adaptive measures correspondingly so as to scientifically deal with the problems of surface water resources in China.
