Hydrological Impacts of Climate Change and Land Use/Land Cover Change

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Hydrology".

Deadline for manuscript submissions: closed (30 April 2019) | Viewed by 52974

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Guest Editor
State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
Interests: image recognition; radar technology; hydrology monitoring; hydrology simulation; artificial intelligence; remote sensing
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Guest Editor
State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
Interests: hydrological impacts of climate change; climate model statistical downscaling; hydrological forecasts; hydrological modelling

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Guest Editor
Department of Geosciences, University of Oslo, N-0316 Oslo, Norway
Interests: hydrological modeling; flood forecasting, regionalization; uncertainty; impact of climate change and land use change; evapotranspiration
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

As presented in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), warming of the climate system is unequivocal during the 20th century, and global warming is likely to further accelerate during the 21st century. Global warming may intensify the global water cycle, exacerbate extreme rainfall and hydrological events, and lead to a global redistribution of water resources at multiple temporal and spatial scales. Thus, watershed water resources management, already stressed with the hazards of natural variability, will face additional challenges. At the same time, the watershed system has been degraded through numerous human modifications, such as the adjustment of cropping system structure, land reclamation, hydraulic engineering construction and urbanization, which may be grouped under the umbrella of land use and/or land cover (LULC) changes. LULC changes feedback on the local and remote climate and hydrological cycles, thus influencing water resource availability, quality and ecosystem services. This Special Issue provides for the publication of high-quality research on  all aspects of investiagting how changes in climate and in LULC affect the hydrological system and its ability to provide crucial services. In addition, we are seeking articles that concentrate on climate and LULC changes as drivers of hydrological system change through their impacts on hydrology and water resources.

Prof. Hua Chen
Prof. Jie Chen
Prof. Chong-Yu Xu
Guest Editors

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Keywords

  • Hydrological Impacts
  • Climate Change
  • Land Use/Land Cover Change
  • Hydrological system

Published Papers (13 papers)

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Research

25 pages, 3809 KiB  
Article
Impacts of Climate Change and Land-Use Change on Hydrological Extremes in the Jinsha River Basin
by Qihui Chen, Hua Chen, Jinxing Wang, Ying Zhao, Jie Chen and Chongyu Xu
Water 2019, 11(7), 1398; https://doi.org/10.3390/w11071398 - 07 Jul 2019
Cited by 39 | Viewed by 5278
Abstract
Hydrological extremes are closely related to extreme hydrological events, which have been and continue to be one of the most important natural hazards causing great damage to lives and properties. As two of the main factors affecting the hydrological cycle, land-use change and [...] Read more.
Hydrological extremes are closely related to extreme hydrological events, which have been and continue to be one of the most important natural hazards causing great damage to lives and properties. As two of the main factors affecting the hydrological cycle, land-use change and climate change have attracted the attention of many researchers in recent years. However, there are few studies that comprehensively consider the impacts of land-use change and climate change on hydrological extremes, and few researchers have made a quantitative distinction between them. Regarding this problem, this study aims to quantitatively distinguish the effects of land-use change and climate change on hydrological extremes during the past half century using the method of scenarios simulation with the soil and water assessment tool (SWAT). Furthermore, the variations of hydrological extremes are forecast under future scenarios by incorporating the downscaled climate simulations from several representative general circulation models (GCMs). Results show that: (1) respectively rising and declining risks of floods and droughts are detected during 1960–2017. The land use changed little during 1980–2015, except for the water body and building land. (2) The SWAT model possesses better simulation effects on high flows compared with low flows. Besides, the downscaled GCM data can simulate the mean values of runoff well, and acceptable simulation effects are achieved for the extreme runoff indicators, with the exception of frequency and durations of floods and extreme low flows. (3) During the period 1970–2017, the land-use change exerts little impact on runoff extremes, while climate change is one of the main factors leading to changes in extreme hydrological situation. (4) In the context of global climate change, the indicators of 3-day max and 3-day min runoff will probably increase in the near future (2021–2050) compared with the historical period (1970–2005). This research helps us to better meet the challenge of probably increased flood risks by providing references to the decision making of prevention and mitigation measures, and thus possesses significant social and economic value. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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13 pages, 1858 KiB  
Article
Groundwater Recharge Decrease Replacing Pasture by Eucalyptus Plantation
by Tiago Souza Mattos, Paulo Tarso Sanches de Oliveira, Murilo Cesar Lucas and Edson Wendland
Water 2019, 11(6), 1213; https://doi.org/10.3390/w11061213 - 10 Jun 2019
Cited by 21 | Viewed by 4816
Abstract
An important unsolved question in hydrology science is the consequence of the Eucalyptus afforestation on groundwater recharge. Here, we assessed recharge estimates before and after converting pasture cover to Eucalyptus plantation. Groundwater levels, recharge, rainfall (P) and actual evapotranspiration (ET [...] Read more.
An important unsolved question in hydrology science is the consequence of the Eucalyptus afforestation on groundwater recharge. Here, we assessed recharge estimates before and after converting pasture cover to Eucalyptus plantation. Groundwater levels, recharge, rainfall (P) and actual evapotranspiration (ET) were evaluated from 2004 through 2016 over an outcrop area of the Guarani Aquifer System (GAS) in the southeastern Brazil. Recharge was estimated using the water-table fluctuation method. We observed a decrease of 100 mm/year in groundwater levels after land use changed from pasture to Eucalyptus. The average recharge decreased from 407 mm/year (27% of mean P) to 194 mm/year (13% of mean P) after land use change over the study area. We found a recharge decrease of 19% in 2012 and 58% in 2013 under similar annual rainfall in comparison with the long-term mean recharge (from 2004 to 2016). Our results indicated that the high values of ET observed in Eucalyptus plantation decreases water availability for recharge. Therefore, our findings are important to agencies for decision-making in water resources regarding the management of land cover and land use. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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16 pages, 4399 KiB  
Article
Model Uncertainty Analysis Methods for Semi-Arid Watersheds with Different Characteristics: A Comparative SWAT Case Study
by Lufang Zhang, Baolin Xue, Yuhui Yan, Guoqiang Wang, Wenchao Sun, Zhanjie Li, Jingshan Yu, Gang Xie and Huijian Shi
Water 2019, 11(6), 1177; https://doi.org/10.3390/w11061177 - 05 Jun 2019
Cited by 8 | Viewed by 3368
Abstract
Distributed hydrological models play a vital role in water resources management. With the rapid development of distributed hydrological models, research into model uncertainty has become a very important field. When studying traditional hydrological model uncertainty, it is very common to use multisite observation [...] Read more.
Distributed hydrological models play a vital role in water resources management. With the rapid development of distributed hydrological models, research into model uncertainty has become a very important field. When studying traditional hydrological model uncertainty, it is very common to use multisite observation data to evaluate the performance of the model in the same watershed, but there are few studies on uncertainty in watersheds with different characteristics. This study is based on the Soil and Water Assessment Tool (SWAT) model, and uses two common methods: Sequential Uncertainty Fitting Version 2 (SUFI-2) and Generalized Likelihood Uncertainty Estimation (GLUE) for uncertainty analysis. We compared these methods in terms of parameter uncertainty, model prediction uncertainty, and simulation effects. The Xiaoqing River basin and the Xinxue River basin, which have different characteristics, including watershed geography and scale, were used for the study areas. The results show that the GLUE method had better applicability in the Xiaoqing River basin, and that the SUFI-2 method provided more reasonable and accurate analysis results in the Xinxue River basin; thus, the applicability was higher. The uncertainty analysis method is affected to some extent by the characteristics of the watershed. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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20 pages, 3868 KiB  
Article
Assessment of Hydrologic Alteration Metrics for Detecting Urbanization Impacts
by Reid D. McDaniel and Frances C. O’Donnell
Water 2019, 11(5), 1017; https://doi.org/10.3390/w11051017 - 15 May 2019
Cited by 12 | Viewed by 3847
Abstract
Urbanization is increasing rapidly and has the potential to alter the hydrologic cycle. It is uncertain if hydrologic alteration metrics developed for large-scale analyses detect the impacts of urbanization. This study tests the ability of two such methods, Indicators of Hydrologic Alteration (IHA) [...] Read more.
Urbanization is increasing rapidly and has the potential to alter the hydrologic cycle. It is uncertain if hydrologic alteration metrics developed for large-scale analyses detect the impacts of urbanization. This study tests the ability of two such methods, Indicators of Hydrologic Alteration (IHA) and streamflow signatures, to detect the effects of urbanization in two watersheds in the southeastern U.S.A. A hydrologic model (HEC-HMS) was used to simulate flows in ungauged upstream tributaries to determine if analysis of flow from a large gauged watershed detects urbanization effects on upstream tributaries. IHA analysis detected trends in time in the watersheds, but the results were the opposite of what would be expected as urbanization increased minimum flows, decreased maximum flows, and decreased flashiness based on the trend in time and comparison with an undeveloped watershed. IHA parameters were more sensitive to urbanization than streamflow signatures. Subcatchments that transitioned from low to moderate or high levels of urbanization had greater levels of hydrologic alteration than was detected at the watershed outlet. Analyses of stream gauge network data may underestimate the importance of urbanization as a watershed characteristic due to scale issues, the variable effects of water management, and the dynamic nature of urbanization. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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18 pages, 2041 KiB  
Article
The Impacts of Climate Variation and Land Use Changes on Streamflow in the Yihe River, China
by Shanshan Xu, Mingzhou Qin, Shengyan Ding, Qinghe Zhao, Huimin Liu, Cangyu Li, Xiaojie Yang, Yanyan Li, Jiaxin Yang and Xiaoyu Ji
Water 2019, 11(5), 887; https://doi.org/10.3390/w11050887 - 27 Apr 2019
Cited by 10 | Viewed by 3173
Abstract
Climate variation and land use changes have been widely recognized as two major factors that impact hydrological processes. However, it is difficult to distinguish their contributions to changes in streamflow. Quantifying their contributions to alteration of streamflow is especially important for the sustainable [...] Read more.
Climate variation and land use changes have been widely recognized as two major factors that impact hydrological processes. However, it is difficult to distinguish their contributions to changes in streamflow. Quantifying their contributions to alteration of streamflow is especially important for the sustainable management of water resources. In this study, the changes in streamflow for the period of 1960–2008 at two stations (Dongwan and Luhun) were analyzed in the Yihe watershed in China based on hydrological data series and climate parameters. Using a non-parametric Mann–Kendall (MK) and Pettitt’s test, as well as Budyko analysis, we first examined the trends of hydroclimatic variables and the breakpoint of annual streamflow over the past 50 years. Subsequently, we evaluated the contributions of annual precipitation (P), potential evapotranspiration (PET), and land use condition (represented by w), respectively, to streamflow variation. We observed a decreasing trend for P, as well as increasing trends for PET and w. Annual streamflow showed a significant downward trend with an abrupt change occurring in 1985 during the period of 1960–2008. Accordingly, we divided the studied period into two sub-periods: period I (1960–1985) and period II (1986–2008). The sensitivity of the streamflow to the different environmental factors concerned in this study differed. Streamflow was more sensitive to P than to PET and w. The decrease in P was the greatest contributor to the decline in streamflow, which accounted for 50.01% for Dongwan and 55.36% for Luhun, followed by PET, which accounted for 24.25% for Dongwan and 24.45% for Luhun, and land use change was responsible for 25.25% for Dongwan and 20.19% for Luhun. Although land use change plays a smaller role in streamflow reduction, land use optimization and adjustment still have great significance for future water resource management, since climate variation is difficult to control; however, the pattern optimization of land use can be achieved subjectively. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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16 pages, 2234 KiB  
Article
Unraveling the Role of Human Activities and Climate Variability in Water Level Changes in the Taihu Plain Using Artificial Neural Network
by Yuefeng Wang, Hossein Tabari, Youpeng Xu, Yu Xu and Qiang Wang
Water 2019, 11(4), 720; https://doi.org/10.3390/w11040720 - 06 Apr 2019
Cited by 7 | Viewed by 2802
Abstract
Water level, as a key indicator for the floodplain area, has been largely affected by the interplay of climate variability and human activities during the past few decades. Due to a nonlinear dependence of water level changes on these factors, a nonlinear model [...] Read more.
Water level, as a key indicator for the floodplain area, has been largely affected by the interplay of climate variability and human activities during the past few decades. Due to a nonlinear dependence of water level changes on these factors, a nonlinear model is needed to more realistically estimate their relative contribution. In this study, the attribution analysis of long-term water level changes was performed by incorporating multilayer perceptron (MLP) artificial neural network. We took the Taihu Plain in China as a case study where water level series (1954–2014) were divided into baseline (1954–1987) and evaluation (1988–2014) periods based on abrupt change detection. The results indicate that climate variables are the dominant driver for annual and seasonal water level changes during the evaluation period, with the best performance of the MLP model having precipitation, evaporation, and tide level as inputs. In the evaluation period, the contribution of human activities to water level changes in the 2000s is higher than that in the 1990s, which indicates that human activities, including the rapid urbanization, are playing an important role in recent years. The influence of human activities, especially engineering operations, on water level changes in the 2000s is more evident during the dry season (March-April-May (MAM) and December-January-February (DJF)). Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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17 pages, 5019 KiB  
Article
Spatial Downscaling of Tropical Rainfall Measuring Mission (TRMM) Annual and Monthly Precipitation Data over the Middle and Lower Reaches of the Yangtze River Basin, China
by Shaodan Chen, Liping Zhang, Dunxian She and Jie Chen
Water 2019, 11(3), 568; https://doi.org/10.3390/w11030568 - 19 Mar 2019
Cited by 22 | Viewed by 3710
Abstract
Precipitation plays an important role in the global water cycle, in addition to material and energy exchange processes. Therefore, obtaining precipitation data with a high spatial resolution is of great significance. We used a geographically weighted regression (GWR)-based downscaling model to downscale Tropical [...] Read more.
Precipitation plays an important role in the global water cycle, in addition to material and energy exchange processes. Therefore, obtaining precipitation data with a high spatial resolution is of great significance. We used a geographically weighted regression (GWR)-based downscaling model to downscale Tropical Rainfall Measuring Mission (TRMM) 3B43 precipitation data over the middle and lower reaches of the Yangtze River Basin (MLRYRB) from a resolution of 0.25° to 1 km on an annual scale, and the downscaled results were calibrated using the geographical differential analysis (GDA) method. At present, either the normalized difference vegetation index (NDVI) or a digital elevation model (DEM) is selected as the environmental variable in the downscaling models. However, studies have shown that the relationship between the NDVI and precipitation gradually weakens when precipitation exceeds a certain threshold. In contrast, the enhanced vegetation index (EVI) overcomes the saturation shortcomings of the NDVI. Therefore, this study investigated the performances of EVI-derived and NDVI-derived downscaling models in downscaling TRMM precipitation data. The results showed that the NDVI performed better than the EVI in the annual downscaling model, possibly because this study used the annual average NDVI, which may have neutralized detrimental saturation effects. Moreover, the accuracy of the downscaling model could be effectively improved after correcting for residuals and calibrating the model with the GDA method. Subsequently, the downscaled rainfall was closer to the actual weather station rainfall observations. Furthermore, the downscaled results were decomposed into fractions to obtain monthly precipitation data, showing that the proposed method by utilizing the GDA method could improve not only the spatial resolution of remote sensing precipitation data, but also the accuracy of data. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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15 pages, 23274 KiB  
Article
Hydrology of the Sirba River: Updating and Analysis of Discharge Time Series
by Paolo Tamagnone, Giovanni Massazza, Alessandro Pezzoli and Maurizio Rosso
Water 2019, 11(1), 156; https://doi.org/10.3390/w11010156 - 16 Jan 2019
Cited by 20 | Viewed by 5888
Abstract
The Sahelian regions are affected by an increasing number of catastrophic floods in recent years as a consequence of climate and land use/land cover changes. River flow data is key to understanding river behavior and develop flood mitigation and prevention strategies. The present [...] Read more.
The Sahelian regions are affected by an increasing number of catastrophic floods in recent years as a consequence of climate and land use/land cover changes. River flow data is key to understanding river behavior and develop flood mitigation and prevention strategies. The present study provides a revision and an update of the existing discharge dataset of the Sirba River with the aim of enhancing the reliability of these data. The revision also includes the recalibration of the Garbey Kourou rating curves. The analysis of the revised discharge time series strengthens the previous findings, evidencing a positive trend in flood frequency and intensity over the entire analyzed period of 1956–2018. This positive trend is more pronounced for the last 40 years due to a significant underestimation of the rating curves used. A relevant finding is a new changepoint in the time series, detected for 2008, which represents the beginning of the period in which the highest flood magnitudes were registered. The effect of land use/land cover changes and climate changes on the water resource is depicted using flow duration curves. This research produces a revised and more reliable discharge time series that will be a new starting point for future hydrological analyses. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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20 pages, 8252 KiB  
Article
Synthetic Impacts of Internal Climate Variability and Anthropogenic Change on Future Meteorological Droughts over China
by Lei Gu, Jie Chen, Chong-Yu Xu, Hui-Min Wang and LiPing Zhang
Water 2018, 10(11), 1702; https://doi.org/10.3390/w10111702 - 21 Nov 2018
Cited by 12 | Viewed by 3953
Abstract
The climate change impacts on droughts have received widespread attention in many recent studies. However, previous studies mainly attribute the changes in future droughts to human-induced climate change, while the impacts of internal climate variability (ICV) have not been addressed adequately. In order [...] Read more.
The climate change impacts on droughts have received widespread attention in many recent studies. However, previous studies mainly attribute the changes in future droughts to human-induced climate change, while the impacts of internal climate variability (ICV) have not been addressed adequately. In order to specifically consider the ICV in drought impacts, this study investigates the changes in meteorological drought conditions for two future periods (2021–2050 and 2071–2100) relative to a historical period (1971–2000) in China, using two multi-member ensembles (MMEs). These two MMEs include a 40-member ensemble of the Community Earth System Model version 1 (CESM1) and a 10-member ensemble of the Commonwealth Scientific and Industrial Research Organization Mark, version 3.6.0 (CSIRO-Mlk3.6.0). The use of MMEs significantly increases the sample size, which makes it possible to apply an empirical distribution to drought frequency analysis. The results show that in the near future period (2021–2050), the overall drought conditions represented by drought frequency of 30- and 50-year return periods of drought duration and drought severity in China will deteriorate. More frequent droughts will occur in western China and southwestern China with longer drought duration and higher drought severity. In the far future period (2071–2100), the nationwide drought conditions will be alleviated, but model uncertainty will also become significant. Deteriorating drought conditions will continue in southwestern China over this time period. Thus, future droughts in southwestern China should be given more attention and mitigation measures need to be carefully conceived in these regions. Overall, this study proposed a method of taking into account internal climate variability in drought assessment, which is of significant importance in climate change impact studies. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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20 pages, 7574 KiB  
Article
Changes of Grassland Rain Use Efficiency and NDVI in Northwestern China from 1982 to 2013 and Its Response to Climate Change
by Juan Chang, Jiaxi Tian, Zengxin Zhang, Xi Chen, Yizhao Chen, Sheng Chen and Zheng Duan
Water 2018, 10(11), 1689; https://doi.org/10.3390/w10111689 - 19 Nov 2018
Cited by 15 | Viewed by 4059
Abstract
The grasslands in arid and semi-arid regions rely heavily on the use of rain, thus, improving rain use efficiency (RUE) is essential for securing sustainable development of grassland ecosystems in these areas with limited rainfall. In this study, the spatial and temporal variabilities [...] Read more.
The grasslands in arid and semi-arid regions rely heavily on the use of rain, thus, improving rain use efficiency (RUE) is essential for securing sustainable development of grassland ecosystems in these areas with limited rainfall. In this study, the spatial and temporal variabilities of RUE for grassland ecosystems over Northwestern China during 1982–2013 were analyzed using the normalized difference vegetation index (NDVI) and precipitation data. Results showed that: (1) Although grassland area has decreased gradually over the past 30 years, the NDVI in most areas showed that the vegetation was gradually restored; (2) The trends of RUE increased in the east of Northwestern China and decreased in the west of Northwestern China. However, the trends of RUE for the high-coverage grasslands (vs. low-coverage grassland) increased (decreased) significantly over the past 30 years. (3) The RUE for the grasslands was positively correlated with air temperature, while it was negatively correlated with the change of annual mean precipitation in northwestern China. Moreover, the obvious RUE increasing trends were found in the vegetation restoration areas, while the RUE decreasing trends appeared in the vegetation degradation areas. This study will be helpful for understanding the impacts of climate change on securing the sustainable development of grassland ecosystems in arid and semi-arid regions. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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11 pages, 496 KiB  
Article
Influence of Land and Water Rights on Land Degradation in Central Asia
by Ekaterina Strikeleva, Iskandar Abdullaev and Tais Reznikova
Water 2018, 10(9), 1242; https://doi.org/10.3390/w10091242 - 14 Sep 2018
Cited by 6 | Viewed by 4015
Abstract
Land degradation is a key issue for Central Asia as an agrarian region. Land degradation in Central Asia is usually seen as a technological challenge and corresponding solutions are associated with the improvement of land-use technology. However, the reality is more complicated and [...] Read more.
Land degradation is a key issue for Central Asia as an agrarian region. Land degradation in Central Asia is usually seen as a technological challenge and corresponding solutions are associated with the improvement of land-use technology. However, the reality is more complicated and multi-faceted. Institutional aspects of land degradation in the region are more prominent and yet unnoticed. De-linked water and land rights, increased land production functions, water infrastructure degradation, a lack of water-use monitoring, and a lack of knowledge among water users constitute the major institutional aspects of land degradation in Central Asia. This paper looks at the linkages between water and land rights and the main aspects of land degradation. The research was built on a literature review, including internationally funded project reports and in-house investigations. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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13 pages, 4770 KiB  
Article
Assessing Regional Climate Models (RCMs) Ensemble-Driven Reference Evapotranspiration over Spain
by Patricia Olmos Giménez and Sandra G. García-Galiano
Water 2018, 10(9), 1181; https://doi.org/10.3390/w10091181 - 04 Sep 2018
Cited by 13 | Viewed by 3632
Abstract
The present work applies a novel methodology of combining multiple Regional Climate Models (RCMs) (or ensemble) that are based on the seasonal and annual variability of temperatures over Spain, which allows for the quantification and reduction of uncertainty in the projections of temperature [...] Read more.
The present work applies a novel methodology of combining multiple Regional Climate Models (RCMs) (or ensemble) that are based on the seasonal and annual variability of temperatures over Spain, which allows for the quantification and reduction of uncertainty in the projections of temperature based-potential evapotranspiration. Reference evapotranspiration (ETo) is one of the most important variables in water budgets. Therefore, the uncertainties in the identification of reliable trends of reference evapotranspiration should be taken into account for water planning and hydrological modeling under climate change scenarios. From the results over Spain, the RCMs ensemble reproduces well the yearly and seasonal temperature observed dataset for the time reference period 1961–1990. An increase in the ensemble-driven ETo for time period 2021–2050 over Spain is expected, which is motivated by an increase in maximum and minimum temperature, with the consequent negative impacts on water availability. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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17 pages, 2545 KiB  
Article
Understanding the Main Causes of Runoff Change by Hydrological Modeling: A Case Study in Luanhe River Basin, North China
by Ting Zhang, Yixuan Wang, Bing Wang and Ping Feng
Water 2018, 10(8), 1028; https://doi.org/10.3390/w10081028 - 03 Aug 2018
Cited by 10 | Viewed by 3213
Abstract
In the traditional point of view, if there is a significant decreasing trend for a runoff time series, while no significant trend for a precipitation series is present, then an unreliable conclusion will be made that the land surface change is the main [...] Read more.
In the traditional point of view, if there is a significant decreasing trend for a runoff time series, while no significant trend for a precipitation series is present, then an unreliable conclusion will be made that the land surface change is the main contributor to the runoff change. To test it, we selected four sub-watersheds in the Luanhe river basin as the study areas where land use has changed severely. We first detected the long-term rainfall and runoff trend by the Mann–Kendall test, Sen’s slope, and the moving average method, and found that the runoff had a decreasing trend at the 0.05 significance level, while the rainfall had no significant trend in all sub-watersheds. Then an orderly cluster analysis and moving T test method were used to detect the change point of the runoff series. We quantified the contributions of the land surface change and climate variability based on Soil and Water Assessment Tool (SWAT), and the contribution of climate variability accounted for more than 50%, which implies that climate change is the main factor of runoff decrease in the study areas. To further test this, a trend analysis of a reconstructed annual runoff time series under undisturbed conditions has been done. The results showed that in some sub-watersheds, although rainfall series had no significant decreasing trend, the runoff series had significant downward trend. This can be explained by the nonlinear relationship between rainfall and runoff. This study came to a different conclusion from the common view, which observes that runoff decrease is mainly caused by land surface change if rainfall series lacks a significantly decreasing trend. Full article
(This article belongs to the Special Issue Hydrological Impacts of Climate Change and Land Use/Land Cover Change)
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