Estimation of the effects of climate change and human activities on runoff in different time scales in the Beichuan River Basin, China

2018 ◽  
Vol 26 (1) ◽  
pp. 103-119 ◽  
Author(s):  
Wang Xianbang ◽  
He Kangning ◽  
Li Ying ◽  
Wang Hui
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Time Scales ◽  
Human Activities ◽  
Different Time Scales

scholarly journals Hydrological Components Variability under the Impact of Climate Change in a Semi-Arid River Basin

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1122 ◽  
Author(s):  
Xuan Zhang ◽  
Yang Xu ◽  
Fanghua Hao ◽  
Chong Li ◽  
Xiao Wang
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Water Flow ◽  
Time Scales ◽  
Positive Impact ◽  
Green Water ◽  
Impact Of Climate Change ◽  
The Impact ◽  
Semi Arid ◽  
Different Time Scales

With increased attention paid to the changes of global climate, the impacts on hydrological processes remain poorly understood in specific basins. In this study, we selected Luanhe River Basin, which is an important source of water supply to Beijing and Hebei, as a case study for the analysis of the combined impact of precipitation and temperature change to hydrological components in a semi-arid river basin. This study investigated the change of the blue water flow (BWF), green water flow (GWF), and green water storage (GWS) by employing the SWAT (Soil and Water Assessment Tool) model and stochastic methods in different time scales during 1960 to 2017. The contribution of climate changes to hydrological change were quantified by 16 hypothetical scenarios by recombining climatic data. The results show that the annual daily maximum and minimum temperature (Tmax, Tmin) increased while their differences (DTR) decreased. However, there was no significant trend in annual precipitation and hydrological components. The trend of precipitation has a positive impact to the change of all three hydrological components. Although precipitation contributes more to changes in hydrological components, more attention also needs to be given to the change of DTR, which has positive impact of GWF that contrasts with that of BWF and GWS. Seasonal scale studies of these changes suggested that more attention should be paid to the climate change in spring and winter when the hydrological components were more sensitive to climate change. Our results summarized hydrological components variability under the impact of climate change and demonstrated the importance of analyses at different time scales, which was expected to provide a reference for water resources management in other semi-arid river basins.

Time-scale dependence of climate-carbon cycle feedbacks for weak perturbations in CMIP5 models

2021 ◽  
Author(s):  
Guilherme Torres Mendonça ◽  
Julia Pongratz ◽  
Christian Reick
Keyword(s):  
Climate Change ◽  
Carbon Cycle ◽  
Time Scales ◽  
Radiative Forcing ◽  
Global Carbon Cycle ◽  
Atmospheric Co2 ◽  
Ice Age ◽  
Cmip5 Models ◽  
Global Carbon ◽  
Different Time Scales

<p>The increase in atmospheric CO2 driven by anthropogenic emissions is the main radiative forcing causing climate change. But this increase is not only a result from emissions, but also from changes in the global carbon cycle. These changes arise from feedbacks between climate and the carbon cycle that drive CO2 into or out of the atmosphere in addition to the emissions, thereby either accelerating or buffering climate change. Therefore, understanding the contribution of these feedbacks to the global response of the carbon cycle is crucial in advancing climate research. Currently, this contribution is quantified by the α-β-γ framework (Friedlingstein et al., 2003). But this quantification is only valid for a particular perturbation scenario and time period. In contrast, a recently proposed generalization (Rubino et al., 2016) of this framework for weak perturbations quantifies this contribution for all scenarios and at different time scales. </p><p>Thereby, this generalization provides a systematic framework to investigate the response of the global carbon cycle in terms of the climate-carbon cycle feedbacks. In the present work we employ this framework to study these feedbacks and the airborne fraction in different CMIP5 models. We demonstrate (1) that this generalization of the α-β-γ framework consistently describes the linear dynamics of the carbon cycle in the MPI-ESM; and (2) how by this framework the climate-carbon cycle feedbacks and airborne fraction are quantified at different time scales in CMIP5 models. Our analysis shows that, independently of the perturbation scenario, (1) the net climate-carbon cycle feedback is negative at all time scales; (2) the airborne fraction generally decreases for increasing time scales; and (3) the land biogeochemical feedback dominates the model spread in the airborne fraction at all time scales. This last result therefore emphasizes the need to improve our understanding of this particular feedback.</p><p><strong>References:</strong></p><p>P. Friedlingstein, J.-L. Dufresne, P. Cox, and P. Rayner. How positive is the feedback between climate change and the carbon cycle? Tellus B, 55(2):692–700, 2003.</p><p>M. Rubino, D. Etheridge, C. Trudinger, C. Allison, P. Rayner, I. Enting, R. Mulvaney, L. Steele, R. Langenfelds, W. Sturges, et al. Low atmospheric CO2 levels during the Little Ice Age due to cooling-induced terrestrial uptake. Nature Geoscience, 9(9):691–694, 2016.</p>

scholarly journals Effects of Climate Change and Human Activities on Soil Erosion in the Xihe River Basin, China

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1085 ◽  
Author(s):  
Shanshan Guo ◽  
Zhengru Zhu ◽  
Leting Lyu
Keyword(s):  
Climate Change ◽  
Soil Erosion ◽  
River Basin ◽  
Air Temperature ◽  
Human Activities ◽  
Sediment Load ◽  
Sudden Increase ◽  
Validation Period ◽  
Total Change ◽  
Calibration Period

Climate change and human activities are the major factors affecting runoff and sediment load. We analyzed the inter-annual variation trend of the average rainfall, air temperature, runoff and sediment load in the Xihe River Basin from 1969–2015. Pettitt’s test and the Soil and Water Assessment Tool (SWAT) model were used to detect sudden change in hydro-meteorological variables and simulate the basin hydrological cycle, respectively. According to the simulation results, we explored spatial distribution of soil erosion in the watershed by utilizing ArcGIS10.0, analyzed the average erosion modulus by different type of land use, and quantified the contributions of climate change and human activities to runoff and sediment load in changes. The results showed that: (1) From 1969–2015, both rainfall and air temperature increased, and air temperature increased significantly (p < 0.01) at 0.326 °C/10 a (annual). Runoff and sediment load decreased, and sediment load decreased significantly (p < 0.01) at 1.63 × 105 t/10 a. In 1988, air temperature experienced a sudden increase and sediment load decreased. (2) For runoff, R2 and Nash and Sutcliffe efficiency coefficient (Ens) were 0.92 and 0.91 during the calibration period and 0.90 and 0.87 during the validation period, for sediment load, R2 and Ens were 0.60 and 0.55 during the calibration period and 0.70 and 0.69 during the validation period, meeting the model’s applicability requirements. (3) Soil erosion was worse in the upper basin than other regions, and highest in cultivated land. Climate change exacerbates runoff and sediment load with overall contribution to the total change of −26.54% and −8.8%, respectively. Human activities decreased runoff and sediment load with overall contribution to the total change of 126.54% and 108.8% respectively. Runoff and sediment load change in the Xihe River Basin are largely caused by human activities.

scholarly journals Total organic carbon sensitivity to climate change from Lake Qinghai sediments at different time scales

2019 ◽  
Vol 31 (5) ◽  
pp. 1468-1478
Author(s):  
ZHANG Yao ◽  
◽  
WU Duo ◽  
ZHANG Huan ◽  
ZHOU Aifeng ◽  
...  
Keyword(s):  
Climate Change ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Time Scales ◽  
Lake Qinghai ◽  
Different Time Scales

scholarly journals Vegetation Changes and Their Response to Global Change Based on NDVI in the Koshi River Basin of Central Himalayas Since 2000

2020 ◽  
Vol 12 (16) ◽  
pp. 6644
Author(s):  
Xue Wu ◽  
Xiaomin Sun ◽  
Zhaofeng Wang ◽  
Yili Zhang ◽  
Qionghuan Liu ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
River Basin ◽  
Human Activities ◽  
Vegetation Change ◽  
Precipitation Trend ◽  
Central Himalayas ◽  
Annual Minimum Temperature ◽  
Vegetation Activity ◽  
Koshi River Basin

Vegetation forms a main component of the terrestrial biosphere owing to its crucial role in land cover and climate change, which has been of wide concern for experts and scholars. In this study, we used MODIS (moderate-resolution imaging spectroradiometer) NDVI (Normalized Difference Vegetation Index) data, land cover data, meteorological data, and DEM (Digital Elevation Model) data to do vegetation change and its relationship with climate change. First, we investigated the spatio-temporal patterns and variations of vegetation activity in the Koshi River Basin (KRB) in the central Himalayas from 2000 to 2018. Then, we combined NDVI change with climate factors using the linear method to examine their relationship, after that we used the literature review method to explore the influence of human activities to vegetation change. At the regional scale, the NDVIGS (Growth season NDVI) significantly increased in the KRB in 2000–2018, with significant greening over croplands in KRB in India. Further, the croplands and forest in the KRB in Nepal were mainly influenced by human interference. For example, improvements in agricultural fertilization and irrigation facilities as well as the success of the community forestry program in the KRB in Nepal increased the NDVIGS of the local forest. Climate also had a certain impact on the increase in NDVIGS. A significant negative correlation was observed between NDVIGS trend and the annual minimum temperature trend (TMN) in the KRB in India, but an insignificant positive correlation was noted between it and the total annual precipitation trend (PRE). NDVIGS significantly decreased over a small area, mainly around Kathmandu, due to urbanization. Increases in NDVIGS in the KRB have thus been mainly affected by human activities, and climate change has helped increase it to a certain extent.

scholarly journals Attribution Analysis of Hydrological Drought Risk Under Climate Change and Human Activities: A Case Study on Kuye River Basin in China

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1958 ◽  
Author(s):  
Zhang ◽  
Wang ◽  
Zhou
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Human Activities ◽  
Large Scale ◽  
Research Area ◽  
Drought Severity ◽  
Drought Risk ◽  
Drought Duration ◽  
Recurrence Period ◽  
The Impact

This study conducted quantitative diagnosis on the impact of climate change and human activities on drought risk. Taking the Kuye river basin (KRB) in China as the research area, we used variation point diagnosis, simulation of precipitation and runoff, drought risk assessment, and attribution quantification. The results show that: (1) the annual runoff sequence of KRB changed significantly after 1979, which was consistent with the introduction of large-scale coal mining; (2) under the same drought recurrence period, the drought duration and severity in the human activity stage were significantly worse than in the natural and simulation stages, indicating that human activities changed the drought risk in this area; and (3) human activities had little impact on drought severity in the short duration and low recurrence period, but had a greater impact in the long duration and high recurrence period. These results provide scientific guidance for the management, prevention, and resistance of drought; and guarantee sustainable economic and social development in the KRB.

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