scholarly journals Understanding the Role of Urbanization on Vegetation Dynamics in Mountainous Areas of Southwest China: Mechanism, Spatiotemporal Pattern, and Policy Implications

2021 ◽  
Vol 10 (9) ◽  
pp. 590
Author(s):  
Li Peng ◽  
Wei Deng ◽  
Ying Liu
Keyword(s):  
Land Surface ◽  
Vegetation Dynamics ◽  
Southwest China ◽  
Policy Implications ◽  
Vegetation Coverage ◽  
Spatiotemporal Pattern ◽  
Mountainous Area ◽  
Mountainous Areas ◽  
Rapid Urbanization ◽  
The Relationship

As an important component of terrestrial ecosystems, the mountainous areas of southwest China are facing eco-environmental stress due to rapid urbanization. This study analyzed the vegetation dynamics during urbanization in 410 counties in the mountainous area of southwest China using trend analysis and bivariate spatial autocorrelation analysis. The results demonstrate the following: (1) The regional differences in the natural background and the stage of economic development resulted in obvious geographical heterogeneity in the relationship between urbanization and vegetation coverage. (2) The relationship between the rate of urbanization level change (RULC) and the slope of the normalized difference vegetation index (NDVI) (Slope−NDVI) in the mountainous areas of southwest China is characterized by an inverted-U-shaped curve. Based on the inflection point (0.206, 57.60) of the inverted-U-shaped curve, the optimal mean annual RULC is 1.37%. (3) The relief degree of the land surface, the gross domestic product (GDP) change rate, and the slope of temperature change are positively correlated with the Slope−NDVI. Overall, an understanding of how urbanization affects vegetation dynamics can inform decisions concerning ecological restoration and urban–rural development in China.

scholarly journals Influence of Land Use and Land Cover Change on Land surface temperature

2021 ◽  
Vol 283 ◽  
pp. 01038
Author(s):  
Jing Sun ◽  
Jing He
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Urban Expansion ◽  
Rapid Urbanization ◽  
Lulc Changes ◽  
The Mean ◽  
The Relationship

The rapid urbanization process has recently led to significant land use and land cover (LULC) changes, thereby affecting the climate and the environment. The purpose of this study is to analyze the LULC changes in Hefei City, Anhui Province, and their relationship with land surface temperature (LST). To achieve this goal, multitemporal Landsat data were used to monitor the LULC and LST between 2005 and 2015. The study also used correlation analysis to analyze the relationship between LST, LULC, and other spectral indices (NDVI, NDBI, and NDWI). The results show that the built-up land has expanded significantly, transforming from 488.26 km2 in 2005 to 575.64 km2 in 2015. It further shows that the mean LST in Hefei city has increased from 284.0 K in 2005 to 285.86 K in 2015. The results also indicate that there is a positive correlation between LST and NDVI and NDBI, while there is a negative correlation between LST and NDWI. This means that urban expansion and reduced water bodies will lead to an increase in LST.

Research on the Relief Degree of Land Surface (RDLS) Calibration Coefficient of Highway in Plateau Mountainous Area

2011 ◽  
Vol 90-93 ◽  
pp. 426-432
Author(s):  
Guo Hua Liang ◽  
Rong Guo Ma ◽  
Chang Sheng Zhang ◽  
Feng Xia Wu
Keyword(s):  
Regression Model ◽  
Land Surface ◽  
Yunnan Province ◽  
Statistical Tests ◽  
Least Square Method ◽  
Least Square ◽  
Basic Data ◽  
Calibration Coefficient ◽  
Mountainous Area ◽  
Mountainous Areas

Different reasons leaded to highway circuitous between plateau mountainous area and plain lightly undulate area were analyzed. The main reason which leaded to highway circuitous is the RDLS was concluded. The regression model between the RDLS and calibration coefficient of different technological levels of highway in plateau mountainous area was acquired by the least square method and the statistical tests based on the RDLS and calibration coefficient basic data. Taken Yunnan Province which is mountainous plateau province for example, the regression model between the RDLS and calibration coefficient was acquired, using the RDLS and Calibration coefficient basic date form all technological levels of highway in Yunnan Province of different elevation plateau mountainous areas.

scholarly journals Spatiotemporal Analysis of Land Use/Cover Patterns and Their Relationship with Land Surface Temperature in Nanjing, China

2020 ◽  
Vol 12 (3) ◽  
pp. 440 ◽  
Author(s):  
Ruci Wang ◽  
Hao Hou ◽  
Yuji Murayama ◽  
Ahmed Derdouri
Keyword(s):  
Land Use ◽  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Social Life ◽  
Series Data ◽  
Rapid Urbanization ◽  
Cooling Effects ◽  
The Relationship ◽  
The City

Rapid urbanization is one of the most concerning issues in the 21st century because of its significant impacts on various fields, including agriculture, forestry, ecology, and climate. The urban heat island (UHI) phenomenon, highly related to the rapid urbanization, has attracted considerable attention from both academic scholars and governmental policymakers because of its direct influence on citizens’ daily life. Land surface temperature (LST) is a widely used indicator to assess the intensity of UHI significantly affected by the local land use/cover (LULC). In this study, we used the Landsat time-series data to derive the LULC composition and LST distribution maps of Nanjing in 2000, 2014, and 2018. A correlation analysis was carried out to check the relationship between LST and the density of each class of LULC. We found out that cropland and forest in Nanjing are helping to cool the city with different degrees of cooling effects depending on the location and LULC composition. Then, a Cellar Automata (CA)-Markov model was applied to predict the LULC conditions of Nanjing in 2030 and 2050. Based on the simulated LULC maps and the relationship between LST and LULC, we delineated high- and moderate-LST related risk areas in the city of Nanjing. Our findings are valuable for the local government to reorganize the future development zones in a way to control the urban climate environment and to keep a healthy social life within the city.

Rainfall Threshold of Rainfall-Induced Landslides Based on Laboratory Test

2013 ◽  
Vol 353-356 ◽  
pp. 1011-1014
Author(s):  
Yan Su ◽  
Jun Bing Qiu ◽  
Yue Ting Du
Keyword(s):  
Rainfall Intensity ◽  
Orthogonal Experiment ◽  
Slope Angle ◽  
Rainfall Threshold ◽  
Vegetation Coverage ◽  
Mountainous Area ◽  
Slope Surface ◽  
Side Slope ◽  
Artificial Rainfall ◽  
The Relationship

A landslide model test under the artificial rainfall was built according to the rainfll-induced landslide in Fujian mountainous area. The rainfall intensity, the slope types (mainly on vegetation coverage) and the grade of side slope were the main factors in the test. The rainfall threshold of rainfall-induced landslide on shallow bedrock was obtained from the test. The relationship between the cumulative precipitation and slope angle and slope surface types was analyzed from the orthogonal experiment by multiple regression analysis. Results show that most slope failures are caused by the infiltration of rainwater. Conclusion show that when the slope angle and vegetation cover are given, critical hazard threshold can be predicted, and the corresponding landslide sliding time can be gained by combining with the rainfall intensity.

scholarly journals Verification of Fractional Vegetation Coverage and NDVI of Desert Vegetation via UAVRS Technology

2020 ◽  
Vol 12 (11) ◽  
pp. 1742 ◽  
Author(s):  
Liang Tang ◽  
Mingzhu He ◽  
Xinrong Li
Keyword(s):  
Remote Sensing ◽  
Root Mean Square Error ◽  
Land Surface ◽  
Meteorological Factors ◽  
Vegetation Coverage ◽  
Mean Square ◽  
Modis Ndvi ◽  
Data Products ◽  
Desert Areas ◽  
The Relationship

Desertification control and scientific evaluation of desert ecosystem sustainability are important issues for countries along the Silk Road Economic Belt. Fractional vegetation coverage (FVC) is used as a quantitative indicator to describe the vegetation coverage of desert ecosystems. Although satellite remote sensing technology has been widely used to retrieve FVC at the regional and global scale, the authenticity evaluation of the inversion results has been flawed. To gain insight into the composition, structure and changes of desert vegetation, it is important to assess the accuracy of FVC and explore the relationship between FVC and meteorological factors. Therefore, we adopted unmanned aerial vehicle remote sensing (UAVRS) technology to verify the inversion results and analyse the practicability of MODIS-NDVI (where NDVI = normalized difference vegetation index) products in desert areas. To provide a new method for the estimation of vegetation coverage in the natural state, the relationships between vegetation coverage and four meteorological factors, namely, land surface temperature, temperature, precipitation and evaporation were analysed. The results showed that using the original MODIS-NDVI data product with a spatial resolution of 250 m to invert vegetation coverage is practical in desert areas (coefficient of determination (R2) = 0.83, root mean square error (RMSE) = 0.052, normalized root mean square error (NRMSE) = 42.94%, mean absolute error (MAE) = 0.007) but underestimates vegetation coverage in the study area. MODIS-NDVI data products are different from the real NDVI in the study area. Correcting MODIS-NDVI data products can effectively improve the accuracy of the inversion. When extracting vegetation coverage in this area, the scale has little effect on the results. There is a significant correlation between precipitation, evaporation and FVC in the area, but the interaction of temperature and land surface temperature with precipitation and evaporation also has a considerable impact on FVC, and evaporation has a substantial impact on FVC values inverted from MODIS-NDVI data (FVCM), When exploring the relationship between vegetation coverage and meteorological elements, if vegetation coverage is retrieved from MODIS-NDVI data products or MODIS-NDVI data, when considering temperature and precipitation, the effect of evaporation should also be considered. In addition, meteorological factors can be used to predict FVC (R2 = 0.7364, RMSE = 0.0623), which provides a new method for estimating FVC in areas with less manual intervention.

scholarly journals Emergy Based Decoupling Analysis of Ecosystem Services on Urbanization: A Case of Shanghai, China

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6139
Author(s):  
Hengyu Pan ◽  
Yong Geng ◽  
Ji Han ◽  
Cheng Huang ◽  
Wenyi Han ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Soil Conservation ◽  
Water Retention ◽  
Practical Importance ◽  
Policy Implications ◽  
Sustainable Urban Development ◽  
Rapid Urbanization ◽  
Study Results ◽  
Decoupling Analysis ◽  
The Relationship

In order to respond to rapid urbanization, understanding the relationships between urbanization and ecosystem services (ESs) is of practical importance to move toward sustainable urban development. In this study, an emergy-GIS based method is proposed to evaluate ESs. Spatiotemporal emergy values of water retention (WR), air purification (AP), carbon sequestration (CS), soil conservation (SC), and biodiversity conservation (BC) were quantified and relationships among these ESs were analyzed by taking China’s largest city, Shanghai, as a case. The decoupling analysis was conducted to study the relationship between urbanization and ESs. Results show that the total value of regulating ESs had declined by 8.24% from 2005 to 2010. Chongming had the largest value of ESs, followed by Pudong. There is a synergetic relationship among AP, CS, and SC, while a tradeoff appears between WR and other services. Irregular “U” shape relationships between the decrease of ESs and urbanization indicators were observed. Results from decoupling analysis show that ESs experienced weak decoupling from urbanization in most districts. Finally, policy implications were raised based on the study results.

scholarly journals Assessing Interannual Urbanization of China’s Six Megacities Since 2000

2019 ◽  
Vol 11 (18) ◽  
pp. 2138 ◽  
Author(s):  
Sisi Yu ◽  
Zengxiang Zhang ◽  
Fang Liu ◽  
Xiao Wang ◽  
Shunguang Hu
Keyword(s):  
Land Surface ◽  
High Speed ◽  
Local Environment ◽  
Urban Land ◽  
Environmental Crisis ◽  
Vegetation Coverage ◽  
Urbanization Process ◽  
Rapid Urbanization ◽  
Urban Land Expansion ◽  
Basic Characteristics

As a large and populous developing country, China has entered the rapid urbanization stage since 2000. Until 2018, China has accounted for nearly 1/5 of global megacities. Understanding their urbanization processes is of great significance. Given the deficiencies of existing research, this study explored the interannual urbanization process of China’s six megacities during 2000–2018 from four aspects, namely, the basic characteristics of urban land expansion, expansion types, cotemporary evolution of urban land–population–economy, and urbanization effects on the local environment. Results indicated that (1) urban lands in China’s six megacities increased by 153.27%, with distinct differences across megacities; (2) all of six megacities experienced the expansion processes from high-speed to low-speed, but they varied greatly in detail; (3) the speeds of urban land expansion in China’s megacities outpaced the population growth but lagged behind in GDP increase; and (4) urbanization has triggered an environmental crisis, which is represented by the decline in vegetation coverage and the increase in land surface temperature in newly expanded urban lands. This study enriched the content of urbanization, supplemented the existing materials of megacities, and provided a scientific reference for designing rational urban planning.

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