Different land management measures and climate change impacts on the runoff – A simple empirical method derived in a mesoscale catchment on the Loess Plateau

Since the early 2000s, the vegetation cover of the Loess Plateau (LP) has increased significantly, which has been fully recorded. However, the effects on relevant eco-hydrological processes are still unclear. Here, we made an investigation on the changes of actual evapotranspiration (ETa) during 2000–2018 and connected them with vegetation greening and climate change in the LP, based on the remote sensing data with correlation and attribution analysis. Results identified that the average annual ETa on the LP exhibited an obvious increasing trend with the value of 9.11 mm yr−1, and the annual ETa trend was dominated by the changes of ETa in the third quarter (July, August, and September). The future trend of ETa was predicted by the Hurst exponent. Partial correlation analysis indicated that annual ETa variations in 87.8% regions of the LP were controlled by vegetation greening. Multiple regression analysis suggested that the relative contributions of potential evapotranspiration (ETp), precipitation, and normalized difference vegetation index (NDVI), to the trend of ETa were 5.7%, −26.3%, and 61.4%, separately. Vegetation greening has a close relationship with the Grain for Green (GFG) project and acts as an essential driver for the long-term development trend of water consumption on the LP. In this research, the potential conflicts of water demanding between the natural ecosystem and social-economic system in the LP were highlighted, which were caused by the fast vegetation expansion.

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Quantifying the Responses of Evapotranspiration and Its Components to Vegetation Restoration and Climate Change on the Loess Plateau of China

Remote Sensing ◽

10.3390/rs13122358 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2358

Author(s):

Linjing Qiu ◽

Yiping Wu ◽

Zhaoyang Shi ◽

Yuting Chen ◽

Fubo Zhao

Keyword(s):

Climate Change ◽

Loess Plateau ◽

Dominant Role ◽

Vegetation Restoration ◽

Vegetation Coverage ◽

Ecological Planning ◽

The Loess Plateau ◽

Canopy Interception ◽

Community Land Model ◽

Spatiotemporal Trends

Quantitatively identifying the influences of vegetation restoration (VR) on water resources is crucial to ecological planning. Although vegetation coverage has improved on the Loess Plateau (LP) of China since the implementation of VR policy, the way vegetation dynamics influences regional evapotranspiration (ET) remains controversial. In this study, we first investigate long-term spatiotemporal trends of total ET (TET) components, including ground evaporation (GE) and canopy ET (CET, sum of canopy interception and canopy transpiration) based on the GLEAM-ET dataset. The ET changes are attributed to VR on the LP from 2000 to 2015 and these results are quantitatively evaluated here using the Community Land Model (CLM). Finally, the relative contributions of VR and climate change to ET are identified by combining climate scenarios and VR scenarios. The results show that the positive effect of VR on CET is offset by the negative effect of VR on GE, which results in a weak variation in TET at an annual scale and an increased TET is only shown in summer. Regardless of the representative concentration pathway (RCP4.5 or RCP8.5), differences resulted from the responses of TET to different vegetation conditions ranging from −3.7 to −1.2 mm, while climate change from RCP4.5 to RCP8.5 caused an increase in TET ranging from 0.1 to 65.3 mm. These findings imply that climate change might play a dominant role in ET variability on the LP, and this work emphasizes the importance of comprehensively considering the interactions among climate factors to assess the relative contributions of VR and climate change to ET.

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A Weighted-Time-Lag Method to Detect Lag Vegetation Response to Climate Variation: A Case Study in Loess Plateau, China, 1982–2013

Remote Sensing ◽

10.3390/rs13050923 ◽

2021 ◽

Vol 13 (5) ◽

pp. 923

Author(s):

Qianqian Sun ◽

Chao Liu ◽

Tianyang Chen ◽

Anbing Zhang

Keyword(s):

Climate Change ◽

Loess Plateau ◽

Time Lag ◽

New Method ◽

Climate Factors ◽

The Loess Plateau ◽

Climate Conditions ◽

Vegetation Growth ◽

Lag Effect

Vegetation fluctuation is sensitive to climate change, and this response exhibits a time lag. Traditionally, scholars estimated this lag effect by considering the immediate prior lag (e.g., where vegetation in the current month is impacted by the climate in a certain prior month) or the lag accumulation (e.g., where vegetation in the current month is impacted by the last several months). The essence of these two methods is that vegetation growth is impacted by climate conditions in the prior period or several consecutive previous periods, which fails to consider the different impacts coming from each of those prior periods. Therefore, this study proposed a new approach, the weighted time-lag method, in detecting the lag effect of climate conditions coming from different prior periods. Essentially, the new method is a generalized extension of the lag-accumulation method. However, the new method detects how many prior periods need to be considered and, most importantly, the differentiated climate impact on vegetation growth in each of the determined prior periods. We tested the performance of the new method in the Loess Plateau by comparing various lag detection methods by using the linear model between the climate factors and the normalized difference vegetation index (NDVI). The case study confirmed four main findings: (1) the response of vegetation growth exhibits time lag to both precipitation and temperature; (2) there are apparent differences in the time lag effect detected by various methods, but the weighted time-lag method produced the highest determination coefficient (R2) in the linear model and provided the most specific lag pattern over the determined prior periods; (3) the vegetation growth is most sensitive to climate factors in the current month and the last month in the Loess Plateau but reflects a varied of responses to other prior months; and (4) the impact of temperature on vegetation growth is higher than that of precipitation. The new method provides a much more precise detection of the lag effect of climate change on vegetation growth and makes a smart decision about soil conservation and ecological restoration after severe climate events, such as long-lasting drought or flooding.

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Potential productivity of the Miscanthus energy crop in the Loess Plateau of China under climate change

Environmental Research Letters ◽

10.1088/1748-9326/8/4/044003 ◽

2013 ◽

Vol 8 (4) ◽

pp. 044003 ◽

Cited By ~ 20

Author(s):

Wei Liu ◽

Tao Sang

Keyword(s):

Climate Change ◽

Loess Plateau ◽

Energy Crop ◽

The Loess Plateau ◽

Potential Productivity

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Nature-Based Solutions to face climate change adaptation and mitigation in Mediterranean watersheds

10.5194/egusphere-egu21-2035 ◽

2021 ◽

Author(s):

Itxaso Ruiz ◽

María José Sanz

Keyword(s):

Climate Change ◽

Climate Change Adaptation ◽

Land Management ◽

Rural Areas ◽

Management Practices ◽

Water Cycle ◽

Climate Change Impacts ◽

Watershed Scale ◽

Sustainable Rural Development ◽

Adaptation And Mitigation

Rural areas of the Mediterranean watersheds face great environmental challenges, where climate change impacts the water cycle, the soil, and biodiversity, which are often priority issues for adaptation. These, have been aggravated by historical land management practices trends. In this context, we propose Nature Based Solutions (NBS) in the form of Sustainable Land Management (SLM) actions at the watershed scale to achieve climate change adaptation and mitigation while promoting other ecosystem services.SLM actions are local adaptation practices that promote sustainable rural development. Thus, we seek the combination of several actions to achieve regional (watershed scale) more integrated approaches. With this study, we aim at proving that NBS, and thus SLM, is a successful tool for alleviating climate change impacts (i.e. water scarcity, enhanced erosion, biodiversity decline) while promoting the role of land in mitigation and enhancing biodiversity in the rural Mediterranean areas.For this, we propose a novel conceptualization of SLM actions that moves from their local application and evaluation to the regional more systemic approaches through their combination. Results show synergies in the atmosphere, biosphere, and hydrosphere, allow for the upscaling of SLM through systemic approaches and point at direct contributions to several Sustainable Development Goals.

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Detecting the Dominant Cause of Streamflow Decline in the Loess Plateau of China Based onthe Latest Budyko Equation

Water ◽

10.3390/w10091277 ◽

2018 ◽

Vol 10 (9) ◽

pp. 1277 ◽

Cited By ~ 6

Author(s):

Jing Zhao ◽

Shengzhi Huang ◽

Qiang Huang ◽

Hao Wang ◽

Guoyong Leng

Keyword(s):

Climate Change ◽

Loess Plateau ◽

Human Activities ◽

Soil Conservation ◽

Potential Evaporation ◽

The Loess Plateau ◽

Study Region ◽

Water And Soil Conservation ◽

The Wei River Basin ◽

Streamflow Change

Quantifying the relative contributions of climate variability and human activity to streamflow change is important for effective water resource use and management. Four sub-catchments of the Wei River Basin (WRB) in the Loess Plateau in China were selected as the study region, where the evolution of parameter α from the latest Budyko equation (Wang-Tang equation) was explored using an 11-year moving window. The elasticity of streamflow was derived from the climatic aridity index, represented by the ratio of annual potential evaporation ( E P ) to annual precipitation ( P ), and catchment characteristics as represented by α . The effects of climate change and human activities on streamflow change during 1971–2010 were quantified with climate elasticity and decomposition methods. The contributions of different types of human activities to streamflow were further empirically determined using the water and soil conservation method. Results indicate that (1) under the same climate condition ( P and E P ), a higher value of α caused an increase in evaporation rate ( E / P ) and a decrease in runoff. Changes in these hydrological variables led to a subsequent reduction in streamflow in the WRB; (2) The absolute value of the precipitation elasticity was larger than the potential evaporation elasticity, indicating that streamflow change was more sensitive to precipitation; (3) The results based on the two methods were consistent. Climate change and human activities contributed to the decrease in streamflow by 29% and 71%, respectively, suggesting that human activities have exerted more profound impacts on streamflow in the study region; (4) Contributions of different water and soil conservation measures to streamflow reduction were calculated and sorted in descending order: Irrigation, industrial and domestic consumption, terrace, afforestation, reservoirs, check-dams, then grass-planting.

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