Effects of Land Use/Cover Change on Atmospheric Humidity in the Midstream Urban Agglomeration along the Yangtze River

2020 ◽  
Vol 09 (06) ◽  
pp. 578-588
Author(s):  
保坭 李
Keyword(s):  
Land Use ◽  
Yangtze River ◽  
Urban Agglomeration ◽  
The Yangtze River ◽  
Atmospheric Humidity ◽  
Effects Of Land Use

scholarly journals Effects of Land Use/Cover Change On Atmospheric Humidity in Three Urban Agglomerations in The Yangtze River Economic

2021 ◽  
Author(s):  
Baoni Li ◽  
Lihua Xiong ◽  
Quan Zhang ◽  
Shilei Chen ◽  
Han Yang ◽  
...  
Keyword(s):  
Land Use ◽  
Air Temperature ◽  
Land Surface ◽  
Yangtze River ◽  
Urban Expansion ◽  
Regional Climate ◽  
Urban Land ◽  
The Yangtze River ◽  
Atmospheric Humidity ◽  
Urban Agglomerations

Abstract Land use/cover change (LUCC) affects regional climate not only through its direct changes of land surface properties, but also through its further modifications of land-atmosphere interactions. Urban land expansion is a typical case of LUCC in highly populated areas, and has been widely discussed about its impacts on regional air temperature, notably known as urban heat island (UHI) effects. Besides air temperature, atmospheric humidity, as another key variable in hydrometeorology and climate, would be inevitably affected by LUCC as well. However, the impacts of LUCC on atmospheric humidity seem to have not been investigated as much as on temperature. We examined atmospheric humidity changes by trend analyses of humidity indicators in three representative urban agglomerations in the Yangtze River Economic Belt (YREB), China during 1965-2017, and found the evident urban dry island (UDI) effects which are characterized by significant humidity decrease and vapor pressure deficit increase. In different urban cores, the severity levels of UDI are different. Furthermore, strong positive correlations between humidity and evapotranspiration, and between evapotranspiration and leaf area were detected during 2001-2017 when cities entered the accelerated stage of land expansion, indicating that LUCC affects regional climate through an ecohydrological way. We speculated that the UDI effect will not appear until urban land expands to a certain scale. Besides, the UHI effect emerged in the early stage of urban expansion, about 5 years earlier than the UDI effect, and has not performed prominently in recent years. This implies that urbanization-induced LUCC may exert a larger influence on UDI than on UHI in the current later period of urban expansion.

Urban dry island effect and its potential underlying mechanisms in the Yangtze River Delta urban agglomeration, China

2020 ◽  
Author(s):  
Baoni Li
Keyword(s):  
Yangtze River ◽  
Regional Climate ◽  
Yangtze River Delta ◽  
Urban Land ◽  
River Delta ◽  
Urban Agglomeration ◽  
The Yangtze River ◽  
Atmospheric Humidity ◽  
Urban Land Expansion ◽  
The Yangtze River Delta

<p>Land use/cover change (LUCC) affects regional climate change not only through its direct changes of land surface properties, but also through its further modifications of land-atmosphere interactions including the surface energy budget, water cycle and carbon cycle. Urban land expansion as a typical case of LUCC, has been widely discussed about its effects on regional climate, notably on temperature and known for urban heat island (UHI). Another important climate variable atmospheric humidity is also seriously affected by LUCC but has not earned as much attention as temperature. We examined atmospheric humidity changes by a series of indicators in the Yangtze River Delta urban agglomeration of China during 1965-2017, and found obvious urban dry land (UDI) effect in the urban cores, as characterized by decreased humidity and increased vapor pressure deficit. Furthermore, we found similar spatial patterns of humidity changes with urban land expansion process and strong correlations of humidity changes with evapotranspiration and leaf area index changes, indicating that LUCC affects regional climate through an ecohydrological way. We suggest that the UDI effect should be paid more attention in future urban planning and landscape design and more quantitative estimations of urban expansion effect on regional and global drying trends are needed.</p>

scholarly journals Impact of Land Use/Cover Change on Yangtze River Delta Urban Agglomeration Ecosystem Services Value: Temporal-Spatial Patterns and Cold/Hot Spots Ecosystem Services Value Change Brought by Urbanization

2019 ◽  
Vol 16 (1) ◽  
pp. 123 ◽  
Author(s):  
Zhigang Li ◽  
Zishu Sun ◽  
Yangjie Tian ◽  
Jialong Zhong ◽  
Wunian Yang
Keyword(s):  
Land Use ◽  
Ecosystem Services ◽  
Hot Spots ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Urban Agglomeration ◽  
The Yangtze River ◽  
The Yangtze River Delta ◽  
Provisioning Services

Land use/cover change (LUCC) from increased urbanization significantly impacts regional ecosystem services. Based on a cold/hot spots analysis, this paper used grain yield, food prices, price index statistics, and a land use thematic map to study the impact of LUCC on four ecosystem services values (ESVs) in the Yangtze River Delta urban agglomeration, and determine the spatial differences resulting from the rapid urbanization LUCC. The correlation between the four ecosystem services was then studied and sensitivity analyses conducted to investigate whether any changes in the ESVs could lead to unacceptable unit value transfer uncertainties. It was found that most urban land was converted from farmland, and that before 2000, the total ESVs and the regulating services values (RSVs) increased significantly, after which it declined, the provisioning services values (PSVs) declined year on year, the habitat services value (HSV) and cultural and amenity services value (CSV) declined sharply after 2000, and the spatial distribution of the four ESVs were significantly different. Over time, it was found that the hot spots were shrinking and the cold spots were spreading. The provisioning services were found to be negatively correlated with habitat services and cultural and amenity services, the regulating services were weakly positively correlated with the provisioning services and significantly positively correlated with the habitat services and cultural and amenity services, and the habitat services were significantly positively correlated with cultural and amenity services. In the Yangtze River Delta urban agglomeration, the water area is the most important for the total ESVs, followed by non-bush forest. Paddy field is ranked third. Dryland, bush, grassland, and wetland are less important. The importance of barren land is almost zero. This research provides the government with a scientific basis from which to formulate spatial planning and environmental protection policies for ecological sustainable development in the Yangtze River Delta urban agglomeration.

scholarly journals Assessment of Ecosystem Health and Its Key Determinants in the Middle Reaches of the Yangtze River Urban Agglomeration, China

2022 ◽  
Vol 19 (2) ◽  
pp. 771
Author(s):  
Fengjian Ge ◽  
Guiling Tang ◽  
Mingxing Zhong ◽  
Yi Zhang ◽  
Jia Xiao ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Planning ◽  
Yangtze River ◽  
Ecosystem Health ◽  
Urban Land Use ◽  
Urban Agglomeration ◽  
The Yangtze River ◽  
Urban Agglomerations ◽  
Surrounding Areas ◽  
City Group

Urban agglomerations have gradually formed in different Chinese cities, exerting great pressure on the ecological environment. Ecosystem health is an important index for the evaluation of the sustainable development of cities, but it has rarely been used for urban agglomerations. In this study, the ecosystem health in the middle reaches of the Yangtze River Urban Agglomeration was assessed using the ecosystem vigor, organization, resilience, and services framework at the county scale. A GeoDetector was used to determine the effects of seven factors on ecosystem health. The results show that: (1) The spatial distribution of ecosystem health differs significantly. The ecosystem health in the centers of Wuhan Metropolis, Changsha–Zhuzhou–Xiangtan City Group, and Poyang Lake City Group is significantly lower than in surrounding areas. (2) Temporally, well-level research units improve gradually; research units with relatively weak levels remain relatively stable. (3) The land use degree is the main factor affecting ecosystem health, with interactions between the different factors. The effects of these factors on ecosystem health are enhanced or nonlinear; (4) The effect of the proportion of construction land on ecosystem health increases over time. The layout used in urban land use planning significantly affects ecosystem health.

scholarly journals The Evolution of the Interactive Relationship between Urbanization and Land-Use Transition: A Case Study of the Yangtze River Delta

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 804
Author(s):  
Bo Niu ◽  
Dazhuan Ge ◽  
Rui Yan ◽  
Yingyi Ma ◽  
Dongqi Sun ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Socioeconomic Factor ◽  
The Yangtze River ◽  
Land Use Transition ◽  
The Yangtze River Delta ◽  
Interaction Relationship

In recent years, the impact of land-use systems on global climate change has become increasingly significant, and land-use change has become a hot issue of concern to academics, both within China and abroad. Urbanization, as an important socioeconomic factor, plays a vital role in promoting land-use transition, which also shows a significant spatial dependence on urbanization. This paper constructs a theoretical framework for the interaction relationship between urbanization and land-use transition, taking the Yangtze River Delta as an example, and measures the level of urbanization from the perspective of population urbanization, economic urbanization and social urbanization, while also evaluating the level of land-use morphologies from the perspective of dominant and recessive morphologies of land-use. We construct a PVAR model and coupled coordination model based on the calculated indexes for empirical analysis. The results show that the relationship between urbanization and land-use transition is not a simple linear relationship, but tends to be complex with the process of urbanization, and reasonable urbanization and land-use morphologies will promote further benign coupling in the system. By analyzing the interaction relationship between urbanization and land-use transition, this study enriches the study of land-use change and provides new pathways for thinking about how to promote high-quality urbanization.

scholarly journals Spatiotemporal Distribution Characteristics and Driving Forces of PM2.5 in Three Urban Agglomerations of the Yangtze River Economic Belt

2021 ◽  
Vol 18 (5) ◽  
pp. 2222
Author(s):  
Jin-Wei Yan ◽  
Fei Tao ◽  
Shuai-Qian Zhang ◽  
Shuang Lin ◽  
Tong Zhou
Keyword(s):  
Geographically Weighted Regression ◽  
Yangtze River ◽  
National Level ◽  
National Development ◽  
Urban Agglomeration ◽  
Spatiotemporal Distribution ◽  
Weighted Regression ◽  
Series Data ◽  
The Yangtze River ◽  
Urban Agglomerations

As part of one of the five major national development strategies, the Yangtze River Economic Belt (YREB), including the three national-level urban agglomerations (the Cheng-Yu urban agglomeration (CY-UA), the Yangtze River Middle-Reach urban agglomeration (YRMR-UA), and the Yangtze River Delta urban agglomeration (YRD-UA)), plays an important role in China’s urban development and economic construction. However, the rapid economic growth of the past decades has caused frequent regional air pollution incidents, as indicated by high levels of fine particulate matter (PM2.5). Therefore, a driving force factor analysis based on the PM2.5 of the whole area would provide more information. This paper focuses on the three urban agglomerations in the YREB and uses exploratory data analysis and geostatistics methods to describe the spatiotemporal distribution patterns of air quality based on long-term PM2.5 series data from 2015 to 2018. First, the main driving factor of the spatial stratified heterogeneity of PM2.5 was determined through the Geodetector model, and then the influence mechanism of the factors with strong explanatory power was extrapolated using the Multiscale Geographically Weighted Regression (MGWR) models. The results showed that the number of enterprises, social public vehicles, total precipitation, wind speed, and green coverage in the built-up area had the most significant impacts on the distribution of PM2.5. The regression by MGWR was found to be more efficient than that by traditional Geographically Weighted Regression (GWR), further showing that the main factors varied significantly among the three urban agglomerations in affecting the special and temporal features.

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