scholarly journals Contributions of Vegetation Greening and Climate Change to Evapotranspiration Trend after Large-Scale Vegetation Restoration on the Loess Plateau, China

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1755
Author(s):  
Shuo Wang ◽  
Chenfeng Cui ◽  
Qin Dai
Keyword(s):  
Climate Change ◽  
Loess Plateau ◽  
Large Scale ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Potential Evapotranspiration ◽  
Development Trend ◽  
Future Trend ◽  
Natural Ecosystem ◽  
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.

scholarly journals Does Vegetation Restoration Change Regional Ecohydrological Condition at the Loess Plateau in China?

2016 ◽  
Vol 6 (4) ◽  
pp. 116
Author(s):  
Xiongwen Chen ◽  
Jianzhi Niu
Keyword(s):  
Loess Plateau ◽  
Large Scale ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Rainfall Intensity ◽  
Vegetation Restoration ◽  
Soil Water Storage ◽  
The Loess Plateau ◽  
Derived Data

The Loess Plateau is a severely eroded and very venerable area in the northwestern China. Large scale vegetation restoration has been conducted in this region during the recent decades, its effect on the regional ecohydrology is under concern. In this study, long term satellite and derived data were used to analyze regional hydrological condition at the major part of the Loess Plateau (35°-37°N and 105°-110° E). The results indicate that there was an increase in the regional normalized difference vegetation index, evapotranspiration, rainfall intensity, soil water storage (surface 1m layer) and runoff. It was also observed that the total annual precipitation did not change significantly.The possible mechanisms may be related to the complicated processes of vegetation on ecohydrology. Our results and approach may be useful to evaluate the benefits of ecological restoration and further vegetation restoration at the Loess Plateau and other regions.

scholarly journals Hydro-climatic and land use/cover changes in Nasia catchment of the White Volta basin in Ghana

2021 ◽  
Author(s):  
Emmanuel Nyadzi ◽  
Enoch Bessah ◽  
Gordana Kranjac-Berisavljevic ◽  
Fulco Ludwig
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Potential Evapotranspiration ◽  
Sunshine Duration ◽  
Climatic Variables ◽  
Northern Ghana ◽  
Maximum Temperature

AbstractThe Nasia catchment is the reservoir with significant surface water resources in Northern Ghana and home to numerous subsistence farmers engaged in rainfed and dry season irrigation farming. Yet, there is little understanding of the hydro-climatic and land use/cover conditions of this basin. This study investigated trends, relationships and changes in hydro-climatic variables and land use/cover in addition to implications of the observable changes in the Nasia catchment over a period of 50 years. Parameters used for the study were minimum (Tmin) and maximum temperature (Tmax), wind speed (WS), sunshine duration (S), rainfall (R), relative humidity (RH), discharge (D) and potential evapotranspiration (PET) data, 15 years of remotely sensed normalized difference vegetation index (NDVI) data and 30 years of land use/cover image data. Results show that Tmin, Tmax, WS and PET have increased significantly (p < 0.05) over time. RH and S significantly declined. R, D and NDVI have not decreased significantly (p > 0.05). A significant abrupt change in almost all hydro-climatic variables started in the 1980s, a period that coincides with the occurrence of drought events in the region, except WS in 2001, R in 1968 and D in 1975, respectively. Also, D showed a positive significant correlation with RH, R and PET, but an insignificant positive relationship with S. D also showed a negative insignificant correlation with Tmin, Tmax and WS. Areas covered with shrubland and settlement/bare lands have increased to the disadvantage of cropland, forest, grassland and water bodies. It was concluded that climate change impact is quite noticeable in the basin, indicating water scarcity and possibilities of droughts. The analysis performed herein is a vital foundation for further studies to simulate and predict the effect of climate change on the water resources, agriculture and livelihoods in the Nasia catchment.

scholarly journals Spatial and Temporal Variations of Potential Evapotranspiration in the Loess Plateau of China During 1960–2017

2020 ◽  
Vol 12 (1) ◽  
pp. 354 ◽  
Author(s):  
Congjian Sun ◽  
Zhenjing Zheng ◽  
Wei Chen ◽  
Yuyang Wang
Keyword(s):  
Climate Change ◽  
Loess Plateau ◽  
Hydrological Cycle ◽  
Climatic Factors ◽  
Potential Evapotranspiration ◽  
Southern Oscillation ◽  
Chinese Loess Plateau ◽  
Future Climate Change ◽  
Strong Positive Correlation ◽  
The Loess Plateau

Potential evapotranspiration (ET0) is an integral component of the hydrological cycle and the global energy balance, and its long-term variation is of much concern in climate change studies. The Loess Plateau is an important area of agricultural civilization and water resources research. This study analyzed the spatial and temporal evolution processes and influential parameters of ET0 at 70 stations in different topographical areas of the Chinese Loess Plateau (CLP). Using the Mann–Kendall trend, Cross wavelet transform, and the ArcGIS platform, the ET0 of each station was quantified using the Penman–Monteith equation, and the effects of climatic factors on ET0 were assessed by analyzing the correlation coefficients and contribution rates of the climatic factors. The results showed that: (1) the overall trend of the ET0 in different terrains of the Loess Plateau is consistent, however, the ET0 values differ; the hill region (HR) has the highest ET0, followed by the valley region (VR), and the mountain region (MR) has the lowest, and ET0 changes differ between seasons. (2) Spatial distribution characteristics of multiyear mean ET0 in the study are as follows: the ET0 values in mountain and hilly areas are decreasing from west to east, and the higher mean annual ET0 value in the VR is mainly concentrated in the eastern CLP. (3) In the past 58 years, the annual mean and the seasonal ET0 of the region showed increasing trends, however, differences in different terrains were obvious. (4) ET0 has significant correlations with El Niño–Southern Oscillation (ENSO), Pacific–North American teleconnection (PNA), and Atlantic Multidecadal Oscillation (AMO). The resonance period of ET0 and ENSO was 3–6 a, mainly in 1976–1985. The mean coherence phase angle was close to 360°, indicating that ET0 lags behind PNA by approximately 2–6 a; ET0 has a very strong positive correlation with AMO. (5) Relative humidity (RH) is the main influencing factor of ET0 change in the Loess Plateau. Temperature (T) variation has the highest contribution rate (42%) to the regional ET0 variation in the entire CLP. We should pay more attention to the variation of evaporation under future climate change, especially temperature change.

scholarly journals Does Anthropogenic Land Use Change Play a Role in Changes of Precipitation Frequency and Intensity over the Loess Plateau of China?

2018 ◽  
Vol 10 (11) ◽  
pp. 1818 ◽  
Author(s):  
Zhengjia Liu ◽  
Yansui Liu
Keyword(s):  
Loess Plateau ◽  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Regional Scale ◽  
Precipitation Amount ◽  
The Loess Plateau ◽  
Precipitation Frequency ◽  
Intensity Changes ◽  
Vegetation Cover Change

Human transformation of landscapes is pervasive and accelerating across the Earth. However, existing studies have not provided a comprehensive picture of how precipitation frequency and intensity respond to vegetation cover change. Therefore, this study took the Loess Plateau as a typical example, and used satellite-based Normalized Difference Vegetation Index (NDVI) data and daily gridded climatic variables to assess the responses of precipitation dynamics to human-induced vegetation cover change. Results showed that the total precipitation amount exhibited little change at the regional scale, showing an upward but statistically insignificant (p > 0.05) trend of 7.6 mm/decade in the period 1982–2015. However, the frequency of precipitation with different intensities showed large variations over most of the Loess Plateau. The number of rainy days (light, moderate, heavy, very heavy and severe precipitation) increased in response to increased vegetation cover, especially in the central-eastern Loess Plateau. Anthropogenic land cover change is largely responsible for precipitation intensity changes. Additionally, this study also observed high spatially explicit heterogeneity in different precipitation intensities in response to vegetation cover change across the Loess Plateau. These findings provide some reference information for our understanding of precipitation frequency and intensity changes in response to regional vegetation cover change in the Loess Plateau.

scholarly journals Temporal Stability of Vegetation Cover across the Loess Plateau Based on GIMMS during 1982–2013

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 315
Author(s):  
Chunyan Zhang ◽  
Shan Guo ◽  
Yanning Guan ◽  
Danlu Cai ◽  
Xiaolin Bian
Keyword(s):  
Soil Erosion ◽  
Loess Plateau ◽  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Environmental Changes ◽  
Temporal Stability ◽  
Reference Conditions ◽  
Reference Period ◽  
The Loess Plateau

The Loess Plateau, covering approximately 640,000 km2, has experienced the most severe soil erosion in the world. A greening tendency has been noticed since implementing the Grain to Green Program (GTGP), which may prevent further soil erosion. Therefore, understanding the underpinning basis of greening stability and persistence is important for sustainable improvement. Global Inventory Modeling and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI) datasets for 1982–2013 were used to investigate the temporal stability and persistent time (PT) of vegetation over the Loess Plateau, utilizing the coefficient of variation (CV) and the estimation of tendencies of vegetation greening starting from the selected reference conditions. Two periods from 1982 to 1999 (as the reference period) and 2000 to 2013 were selected by considering the GTGP since 1999. The results indicate that: (1) A significant increase in vegetation cover occurred in the low NDVI area (NDVI < 0.3), with a high fluctuation from 2000 to 2013 compared with the reference period. Moreover, the fluctuation in vegetation is more related to precipitation variation since 1999. (2) Most areas recovered in the greening trend of the first period starting in 2009, occurring in 28.7% (2628 of 9148) of the total area. (3) The revegetated areas have a low PT and a high CVvi, that is, the revegetated areas need a long time to recover from disturbances. Therefore, we identify the sensitive areas with PT = 4; further management needs to be implemented for sustainable development in these areas. These results provide a method to quantify the stability and persistence of the complex interactions between vegetation greenness and environmental changes, particularly in fragile areas.

scholarly journals Spatial–Temporal Variation Characteristics of Multiple Meteorological Variables and Vegetation over the Loess Plateau Region

2020 ◽  
Vol 10 (3) ◽  
pp. 1000 ◽  
Author(s):  
Qingzhi Zhao ◽  
Xiongwei Ma ◽  
Liang Liang ◽  
Wanqiang Yao
Keyword(s):  
Climate Change ◽  
Correlation Coefficient ◽  
Loess Plateau ◽  
Vegetation Index ◽  
Meteorological Factors ◽  
The Loess Plateau ◽  
Plateau Region ◽  
Vegetation Growth ◽  
Climatic Indices ◽  
Temperature Range

Ecological restoration and climate change in the Loess Plateau region have become research hotspots. Climate change and anthropogenic activities have led to spatial–temporal pattern variations in vegetation and extreme climatic indices and meteorological factors. Therefore, obtaining a better understanding is necessary of the internal relations between vegetation and meteorological factors. In this paper, the interplay between vegetation index and various factors, including extreme climatic indices and meteorological factors, during a long-term time series is investigated using Mann–Kendall trend analysis, and Pearson correlation coefficient analysis. The mechanisms of interaction between vegetation growth and various factors in the Loess Plateau are then analyzed. Results reveal that (i) the rapid growth of vegetation during 2000–2015 has made a major contribution to the growth trend of the Loess Plateau in the past 33 years (1982–2015). During 2000–2015, the increase of vegetation may inhibit the increase of extreme warm index and the decrease of extreme cold index; (ii) a warm and dry climate developed with decreasing relative humidity and increasing temperature; (iii) the normalized vegetation index (NDVI) is strongly correlated with extreme climatic indices and meteorological factors, especially precipitable water vapor (PWV), with a correlation coefficient of 0.94; and (iv) the daily temperature range, diurnal temperature range and sunshine duration (SSD) exerted different time-delay effects on vegetation growth in the Loess Plateau. The above findings provide an essential theoretical basis for ecological policy formulation in the Loess Plateau.

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