scholarly journals Streamflow and its components in Ebinur basin: decoupling of anthropogenic and climatic elements

2021 ◽  
Author(s):  
bao qingling ◽  
ding jianli ◽  
liu jie ◽  
han lijie ◽  
wang yinghui
Keyword(s):  
Climate Change ◽  
Human Activity ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Junggar Basin ◽  
Anthropogenic Factors ◽  
Lake Basin ◽  
Infiltration Capacity ◽  
Area Index ◽  
Impact Phase

Detecting and assessing changes in the hydrological cycle and how it responds to a changing environment is essential for maintaining regional ecological security and restoring damaged ecosystems. The Ebinur Lake basin, an important ecological barrier in the Junggar Basin of Xinjiang, China, has undergone significant changes in recent decades as a result of massive eco-rehabilitation projects and increased anthropogenic factors. Former studies concentrated on the effect of environmental changes on total runoff, while studies on runoff components in arid region were absent. To solve the above defects, we separated the study period into three phases based on the heuristic segmentation algorithm：the reference phase (1964-1985) and two impact phases: I (1986-2000) and II (2001-2017). The Variable Infiltration Capacity (VIC) surface models were used to determine the contribution of both human activities and climate change to streamflow along with its components. Based on the VIC model of streamflow splitting, the results showed that surface runoff, baseflow and snowmelt accounted for 20.97%, 60.37% and 23.42% of the annual runoff volume respectively. The differential evolution Markov chain (DEMC) algorithm improved the Nash-Sutcliffe efficiency by 20% over the traditional SCE-UA algorithm, which exceeded 0.6 and reached reliable level. Increases in cropland and forested land were partially contributed by grassland and heathland throughout the study period, While the leaf area index (LAI) of the season of plant growth showed a trend of 0.002 increase per year. Direct human activity was the main factor in the reduction of runoff in impact phase I and indirect human activity in impact phase II, Whereas, in the total impact phase, climate change was the main driver of runoff increase. Our results provide insight into decision making related to water stress in changing circumstances in arid regions.

scholarly journals Impacts of regional climate and teleconnection on hydrological change in the Bosten Lake Basin, arid region of northwestern China

2017 ◽  
Vol 9 (1) ◽  
pp. 74-88 ◽  
Author(s):  
Huaijun Wang ◽  
Yingping Pan ◽  
Yaning Chen
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Large Scale ◽  
Southern Oscillation ◽  
Polar Vortex ◽  
Circulation Index ◽  
Lake Basin ◽  
Area Index ◽  
Bosten Lake

Abstract This investigation examined effects of climate change, measured as annual, seasonal, and monthly air temperature and precipitation from 1958 to 2010, on water resources (i.e., runoff) in the Bosten Lake Basin. Additionally, teleconnections of hydrological changes to large-scale circulation indices including El Nino Southern Oscillation (ENSO), Arctic Oscillation (AO), North Atlantic Oscillation (NAO), Tibetan High (XZH), westerly circulation index (WI), and northern hemisphere polar vortex area index (VPA) were analyzed in our study. The results showed the following. (1) Annual and seasonal air temperature increased significantly in the Bosten Lake Basin. Precipitation exhibited an increasing trend, while the significance was less than that of temperature. Abrupt changes were observed in 1996 in mountain temperature and in 1985 in plain temperature. (2) Runoff varied in three stages, decreasing before 1986, increasing from 1987 to 2003, and decreasing after 2003. (3) Precipitation and air temperature have significant impacts on runoff. The hydrological processes in the Bosten Lake Basin were (statistically) significantly affected by the northern hemisphere polar vortex area index (VPA) and the Tibetan High (XZH). The results of this study are good indicators of local climate change, which can enhance human mitigation of climate warming in the Bosten Lake Basin.

Historical environmental changes in the Poyang Lake basin (Yangtze River, China) and impacts on agricultural activities

The Holocene ◽  
2021 ◽  
pp. 095968362110477
Author(s):  
Maofeng He ◽  
Fengxian Bu ◽  
Claudio O Delang ◽  
Jialin Xie ◽  
Quan Ye ◽  
...  
Keyword(s):  
Climate Change ◽  
Lake Water ◽  
Human Activities ◽  
Environmental Changes ◽  
Poyang Lake ◽  
Lake Basin ◽  
Lake Area ◽  
Poyang Lake Basin ◽  
Past 2000 Years ◽  
Floods And Droughts

Climate change and human activities have been an important part of studies regarding historical environmental changes in China over the past 2000 years. In this study, we focused on environmental changes, that is, natural disasters and human activities, in the Poyang Lake Basin over the past 2000 years, to analyze interactions between land use cover changes and human activities from the perspective of regional sustainable development. We collected historical records of climate and hydrology, floods and droughts, and rivers and lakes in the Poyang Lake area, and established time sequences for the floods and droughts, lake water level and lake area, amount of farming land, and population, in order to discuss interactions between changes in the environment and the climate, with emphasis on the impacts of extreme events on lake and river basin environment changes. The following results were obtained. First, climate changes in historical periods had wide-ranging and far-reaching impacts on agricultural production, especially disasters caused by climate change. Among the changes in the Poyang Lake basin environment, including river network systems, lake water levels, etc., changes in lake water volume are direct evidence of climate change, adaptation to climate change, and obvious phased characteristics. Second, in the process of changes to the lake and river network in the Poyang Lake Basin, social and economic development is accompanied by evolution of the lake. Increases and decreases in population, the scale of agricultural production, and lake environment changes have direct and significant interactions. Third, the Poyang Lake basin’s environmental changes during the historical period are mainly reflected in the pressure feedback mode of “population–agriculture” in the lake environment.

scholarly journals Detection and Attribution of Runoff Reduction of Weihe River over Different Periods during 1961–2016

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1416 ◽  
Author(s):  
Shuai Yang ◽  
Tingting Kang ◽  
Jingyi Bu ◽  
Jiahao Chen ◽  
Zhipeng Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Human Activity ◽  
Water Yield ◽  
Infiltration Capacity ◽  
Detection And Attribution ◽  
Runoff Reduction ◽  
Runoff Variability ◽  
Weihe River ◽  
Stage Characteristic

An obvious decline in runoff of the Weihe River has been detected during the last half-century. Climate change and human activity acted as two major factors inducing the reduction. However, little knowledge is acquired on how and to what extent the decadal climate change and human activity induced runoff variations, which is essential for regional water resources planning and management. In this study, the observed data of 3 hydrological stations and 31 meteorological stations were used to analyze the runoff variability, and Variable Infiltration Capacity (VIC) model (Xu Liang, Seattle, WA, United States of America) coupled with scenario simulation was employed to attribute runoff variation of each period. The results showed that runoff decreased significantly at a rate of −1.01 × 108 m3·year−1 with obvious stage characteristic during 1961–2016. The water yield was highest in the 1960s and varying degrees of decline were detected in the following periods, resulting in a decrease of available freshwater by 20.54%–58.24%. Human activity had a dominant contribution to induce an increasing runoff decline from 2.068 to 5.776 km3, while the effect of climate was relatively small and lead to runoff reduction, except in the 1970s. This study gave a comprehensive understanding of time-varying runoff variability and highlighted the importance of appropriate human intervention with respect to climate change to ensure water resources security.

Anthropogenic causes of landslides and their implications for monitoring

2021 ◽  
Author(s):  
Kaushik Ramanathan ◽  
Nirmala Vasudevan
Keyword(s):  
Climate Change ◽  
Natural Hazards ◽  
Human Activity ◽  
Global Climate ◽  
Extreme Weather Events ◽  
Anthropogenic Factors ◽  
Human Beings ◽  
Landslide Occurrence ◽  
Landslide Event ◽  
The Impact

<p>Are we justified in referring to all landslides as natural hazards? With the effects of climate change, landslide incidences are increasing all over the world, and many of them accompany floods and occur due to extreme weather events. It has been unequivocally established that humans are responsible for global climate change. Further, landslides also occur in deforested areas. Even if one were to discount the effects of deforestation on climate change and the subsequent occurrence of landslides, one cannot ignore the fact that deforestation leads to slope instabilities in multiple ways. It decreases the effective retaining strength of the slope materials and also exposes more slope material to weathering and consequent leaching. Thus, deforestation and climate change, caused directly or indirectly by human beings, have a significant bearing on landslide occurrence. Furthermore, several catastrophic landslides in recent times have occurred due to indiscriminate human activity, such as constructing dams and other structures on fragile slopes, blasting slopes for road construction without providing adequate toe support, excessive mining, constructing faulty retaining structures on unstable slope material, etc. Over the years, such human activity has resulted in landslides of all types and at various scales. Whether a landslide is natural, caused due to anthropogenic factors, or a combination of the two, the investigation approach and monitored parameters remain the same; we still need to identify the various causative factors and quantify their rates of change over time in the run up to the landslide event. However, we need a paradigm shift in our perspective and treatment of landslides. We need to accept that human activity is, or can be, responsible for landslide occurrence. With this change in perspective, we would monitor slopes with an increased awareness that human actions could negatively impact slope stability. This, in turn, would entail monitoring at every stage to ensure that no human activity adversely impacts the natural balance, thus paving the way for truly sustainable development. We would be doing great disservice to the investigation and monitoring of landslides by such preconceived notions as all landslides are natural hazards. It is high time that we accept our part in compounding the problem of landslide occurrences and come up with solutions to monitor the impact of human activity on the environment to prevent landslides.</p>

scholarly journals Flash-flooding of Ephemeral Streams in the Context of Climate Change

2020 ◽  
Author(s):  
A.M. Camarasa-Belmonte
Keyword(s):  
Climate Change ◽  
River Water ◽  
Flood Control ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Flash Flood ◽  
Intermittent Flow ◽  
Ephemeral Streams ◽  
Basin Scale ◽  
Flood Generation

Ephemeral streams, which are more extended than expected, entail a significant flood risk. Historically they have been underestimated due to their intermittent flow and the lack of knowledge on their hydro-geomorphology. Currently, European legislation recognizes their associated risk and supports research into them, adapting the scale and methodology to their characteristics. Based on the compilation of various works carried out in four Valencian catchments (Eastern Spain), this paper approaches the key questions of rainfall-runoff conversion and flood generation in ephemeral streams, taking into account their hydro-geomorphological specificity. Moreover, the consequences which derive from current environmental changes are addressed in the wider scale of Júcar River Water Authority.The study is based on 5-minute data, registered by the SAIH-Júcar network (Authomatic Hydrological Information System). The investigation has been conducted in two phases. Firstly, key issues determining flash-flood generation at basin scale have been addressed, based on the study of 138 floods, registered between 1989 and 2018, in four Valencian ephemeral streams (Barranc del Carraixet, Rambla de Poyo, Riu Vernissa and Rambla de Gallinera). Secondly, concerning a broader scale (Júcar River Water Authority), the evolution of 698 rain episodes (1989-2007) has been analysed. Finally, the consequences that environmental changes (climatic, anthropogenic and morphogenetic) might mean for flash-flood generation have been discussed.The results show how environmental changes point towards an increase in risk to the detriment of resource. Rain episodes tend to increase in intensity and decrease accumulated precipitation. As a consequence, hydrological connectivity will become more dependent on rain intensity, thus reducing runoff thresholds and basin response times. Anthropic changes enhance this behaviour, reducing infiltration and increasing surface runoff and erosion, while accelerating the hydrological cycle. An increase in process-form disequilibrium in Mediterranean catchments can be expected due to the increase in morphogenetic phases (because of the intensification of events) and a decrease in the efficiency of low-magnitude recovery episodes.Consequently, the behaviour of ephemeral-streams under current climate change conditions points firstly to an increase in intense flash-flood events, which will be difficult to manage with the current flood control measures, and secondly an increase in the general aridity conditions of catchments.

scholarly journals Evaluating the Impacts of Climate Change and Vegetation Restoration on the Hydrological Cycle over the Loess Plateau, China

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2241 ◽  
Author(s):  
Yang ◽  
Kang ◽  
Bu ◽  
Chen ◽  
Gao
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Land Cover ◽  
Loess Plateau ◽  
Hydrological Cycle ◽  
Management Strategies ◽  
The Loess Plateau ◽  
Infiltration Capacity ◽  
Deep Soil ◽  
The Impact

In recent decades, both observation and simulation data have demonstrated an obvious decrease in runoff and soil moisture, with increasing evapotranspiration, over the Loess Plateau. In this study, we employed a Variable Infiltration Capacity model coupled with scenario simulation to explore the impact of change in climate and land cover on four hydrological variables (HVs) over the Loess Plateau, i.e., evapotranspiration (ET), runoff (Runoff), shallow soil moisture (SM1), and deep soil moisture (SM2). Results showed precipitation, rather than temperature, had the closest relationship with the four HVs, with r ranging from 0.76 to 0.97 (p < 0.01), and this was therefore presumed to be the dominant climate-based driving factor in the variation of hydrological regimes. Vegetation conversion, from cropland and grassland to woodland, significantly reduced runoff and increased soil moisture consumption, to sustain an increased ET, and, assuming that the reduction of SM2 is entirely evaporated, we can attribute 71.28% ± 18.64%, 65.89% ± 24.14% of the ET increase to the water loss of SM2 in the two conversion modes, respectively. The variation in HVs, induced by land cover change, were higher than the expected climate change with respect to SM1, while different factors were selected to determine HVs variation in six catchments, due to differences in the mode and intensity of vegetation conversion, and the degree of climate change. Our findings are critical for understanding and quantifying the impact of climate change and vegetation conversions, and provide a further basis for the design of water resources and land-use management strategies with respect to climate change, especially in the water-limited Loess Plateau.

scholarly journals An Improved Conceptual Model Quantifying the Effect of Climate Change and Anthropogenic Activities on Vegetation Change in Arid Regions

2019 ◽  
Vol 11 (18) ◽  
pp. 2110
Author(s):  
Yu ◽  
Yang ◽  
Li ◽  
Yang
Keyword(s):  
Climate Change ◽  
Conceptual Model ◽  
Arid Regions ◽  
Vegetation Change ◽  
Hydrological Cycle ◽  
Anthropogenic Activities ◽  
Regional Scale ◽  
Anthropogenic Activity ◽  
Area Index ◽  
The Impact

Vegetation shows a greening trend on the global scale in the past decades, which has an important effect on the hydrological cycle, and thus quantitative interpretation of the causes for vegetation change is of great benefit to understanding changes in ecology, climate, and hydrology. Although the Donohue13 model, a simple conceptual model based on gas exchange theory, provides an effective tool to interpret the greening trend, it cannot be used to evaluate the impact from land use and land cover change (LULCC) on the regional scale, whose importance to vegetation change has been demonstrated in a large number of studies. Hence, we have improved the Donohue13 model by taking into account the change in vegetation cover ratio due to LULCC, and applied this model to the Yarkand Oasis in the arid region of northwest China. The estimated change trend in leaf area index (LAI) is 1.20%/year from 2001 to 2017, which accounts for approximately half of the observed (2.31%/year) by the moderate resolution imaging spectroradiometer (MODIS). Regarding the causes for vegetation greening, the contributions of: (1) LULCC; (2) atmospheric CO2 concentration; and (3) vapor pressure deficit were: (1) 88.3%; (2) 40.0%; and (3) −28.3%, respectively, which reveals that the largest contribution was from LULCC, which is probably driven by increased total water availability in whole oasis with a constant transpiration in vegetation area. The improved Donohue13 model, a simple but physics-based model, can partially explain the impact of factors related to climate change and anthropogenic activity on vegetation change in arid regions. It can be further combined with the Budyko hypothesis to establish a framework for quantifying the changes in coupled response of vegetation and hydrological processes to environment changes.

Climate change and water resources in the Lower Mekong River Basin: putting adaptation into the context

2010 ◽  
Vol 1 (2) ◽  
pp. 103-117 ◽  
Author(s):  
M. Keskinen ◽  
S. Chinvanno ◽  
M. Kummu ◽  
P. Nuorteva ◽  
A. Snidvongs ◽  
...  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Climate Change Adaptation ◽  
Environmental Changes ◽  
Hydrological Cycle ◽  
Climate Change Impacts ◽  
Mekong River ◽  
Adaptation To Climate Change ◽  
Mekong River Basin ◽  
Spatial And Temporal Scales

Adaptation to climate change has become one of the focal points of current development discussion. This article summarises the findings from a multidisciplinary research project looking at climate change impacts and adaptation in the Mekong River Basin in Southeast Asia. The research highlights the central role that the hydrological cycle has in mediating climate change impacts on ecosystems and societies. The findings indicate that climate change should not be studied in isolation, as there are several other factors that are affecting the hydrological cycle. In the Mekong, the most important such factor is the on-going hydropower development that is likely to induce changes at least as radical as climate change, but with shorter timescales. The article concludes that climate change adaptation should broaden its view to consider environmental changes likely to occur due to different factors at various spatial and temporal scales. It is also important to recognise that climate change adaptation is a dynamic, development-orientated process that should consider also broader socio-political context. To enable this, we propose that an area-based adaptation approach should be used more actively to complement the dominant sector-based approaches.

scholarly journals Disentangling the roles of land-use-related drivers on vegetation greenness across China

2021 ◽  
Author(s):  
LinLing Tang ◽  
Xiaoling Chen ◽  
Xiaobin Cai ◽  
Jian Li
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Land Use ◽  
Urban Area ◽  
Vegetation Dynamics ◽  
Bayesian Model Averaging ◽  
Environmental Changes ◽  
Area Index ◽  
Vegetation Greenness ◽  
Carbon Dioxide Fertilization

Abstract Quantifying the drivers of terrestrial vegetation dynamics is critical for monitoring ecosystem carbon sequestration and bioenergy production. Large scale vegetation dynamics can be observed using the Leaf Area Index (LAI) derived from satellite data as a measure of “greenness”. Previous studies have quantified the effects of climate change and carbon dioxide fertilization on vegetation greenness. In contrast, the specific roles of land-use-related drivers (LURDs) on vegetation greenness have not been characterized. Here, we combined the Interior-Point Method-optimized ecosystem model and the Bayesian model averaging statistical method to disentangle the roles of LURDs on vegetation greenness in China from 2000 to 2014. Results showed a significant increase in growing season LAI (greening) over 35% of the land area of China, whereas less than 6% of it exhibited a significantly decreasing trend (browning). The overall impact of LURDs on vegetation greenness over the whole country was comparatively low. However, the local effects of LURDs on the greenness trends of some specified areas were considerable due to afforestation and urbanization. Southern Coastal China had the greatest area fractions (35.82% of its corresponding area) of the LURDs effects on greening, following by Southwest China. It was because of these economic regions with great afforestation programs. Afforestation effects could explain 27% of the observed greening trends in the forest area. In contrast, the browning impact caused by urbanization was approximately three times of the greening effects of both climate change and carbon dioxide fertilization on the urban area. And they made the urban area had a 50% decrease in LAI. The effects of residual LURDs only accounted for less than 8% of the corresponding observed greenness changes. Such divergent roles would be valuable for understanding changes in local ecosystem functions and services under global environmental changes.

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