Mapping seasonal impervious surface dynamics in Wuhan urban agglomeration, China from 2000 to 2016

2018 ◽  
Vol 70 ◽  
pp. 51-61 ◽  
Author(s):  
Lei Zhang ◽  
Ming Zhang ◽  
Yibin Yao
Keyword(s):  
Impervious Surface ◽  
Urban Agglomeration ◽  
Surface Dynamics ◽  
Wuhan Urban Agglomeration

scholarly journals GISD30: global 30-m impervious surface dynamic dataset from 1985 to 2020 using time-series Landsat imagery on the Google Earth Engine platform

2021 ◽  
Author(s):  
Xiao Zhang ◽  
Liangyun Liu ◽  
Tingting Zhao ◽  
Yuan Gao ◽  
Xidong Chen ◽  
...  
Keyword(s):  
Time Series ◽  
Landsat Imagery ◽  
Impervious Surface ◽  
Google Earth ◽  
Reflectance Spectra ◽  
Impervious Surfaces ◽  
Surface Dynamics ◽  
Google Earth Engine ◽  
Surface Dynamic ◽  
Spatiotemporal Consistency

Abstract. Accurately mapping impervious surface dynamics has great scientific significance and application value for urban sustainable development research, anthropogenic carbon emission assessment and global ecological environment modeling. In this study, a novel and accurate global 30 m impervious surface dynamic dataset (GISD30) for 1985 to 2020 was produced using the spectral generalization method and time-series Landsat imagery, on the Google Earth Engine cloud-computing platform. Firstly, the global training samples and corresponding reflectance spectra were automatically derived from prior global 30 m land-cover products after employing the multitemporal compositing method and relative radiometric normalization. Then, spatiotemporal adaptive classification models, trained with the migrated reflectance spectra of impervious surfaces from 2020 and pervious surface samples in the same epoch for each 5° × 5° geographical tile, were applied to map the impervious surface in each period. Furthermore, a spatiotemporal consistency correction method was presented to minimize the effects of independent classification errors and improve the spatiotemporal consistency of impervious surface dynamics. Our global 30 m impervious surface dynamic model achieved an overall accuracy of 91.5 % and a kappa coefficient of 0.866 using 18,540 global time-series validation samples. Cross-comparisons with four existing global 30 m impervious surface products further indicated that our GISD30 dynamic product achieved the best performance in capturing the spatial distributions and spatiotemporal dynamics of impervious surfaces in various impervious landscapes. The statistical results indicated that the global impervious surface has doubled in the past 35 years, from 5.116 × 105 km2 in 1985 to 10.871 × 105 km2 in 2020, and Asia saw the largest increase in impervious surface area compared to other continents, with a total increase of 2.946 × 105 km2. Therefore, it was concluded that our global 30 m impervious surface dynamic dataset is an accurate and promising product, and could provide vital support in monitoring regional or global urbanization as well as in related applications. The global 30 m impervious surface dynamic dataset from 1985 to 2020 generated in this paper is free to access at http://doi.org/10.5281/zenodo.5220816 (Liu et al., 2021b).

scholarly journals How Do Population Flows Promote Urban–Rural Integration? Addressing Migrants’ Farmland Arrangement and Social Integration in China’s Urban Agglomeration Regions

Land ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 86
Author(s):  
Yanan Li ◽  
Chan Xiong ◽  
Yan Song
Keyword(s):  
Social Integration ◽  
Rural Areas ◽  
Positive Impact ◽  
Central City ◽  
Urban Agglomeration ◽  
Resource Flows ◽  
Urban Rural ◽  
Wuhan Urban Agglomeration ◽  
Urban And Rural Areas ◽  
High Degree

China’s urban–rural relationships have been changed dramatically by the intensifying population flows, especially in urban agglomeration regions. This study contributes to the interpretation of urban–rural integration mechanisms in urban agglomeration by constructing a conceptual framework of migration-related resource flows. Taking the Wuhan urban agglomeration as an example, migrants’ farmland arrangement, migration pattern, and social integration have been investigated to uncover the spatial and temporal characteristics of the urban–rural interaction, based on the data from the China Migrants Dynamic Survey in 2012–2017. The findings indicate that the farmland circulation in the Wuhan urban agglomeration was generally low, but slightly higher than that of the national average. The central city, Wuhan, had a high degree of family migration and social integration, indicating stronger resource flows in developed areas. However, its farmland circulation level was lower than that of non-central cities. The unsynchronized interaction of resources in urban and rural areas should be taken seriously, especially in areas with a relatively developed urban economy. The advantages of the central city in absorbing and settling migrants confirmed the positive impact of the urban agglomeration on promoting urban–rural integration.

Evaluation of water security: an integrated approach applied in Wuhan urban agglomeration, China

2012 ◽  
Vol 66 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Dongguo Shao ◽  
Fengshun Yang ◽  
Chun Xiao ◽  
Xuezhi Tan
Keyword(s):  
Flood Control ◽  
Evaluation Model ◽  
Water Environment ◽  
Rank Correlation ◽  
Water Security ◽  
Integrated Approach ◽  
Urban Agglomeration ◽  
State Of Water ◽  
Wuhan Urban Agglomeration ◽  
Good Agreement

To evaluate water security, the Water Resources Sustainability Evaluation Model has been developed. The model employs four criteria (economic development, flood control security, water supply security, and water environment security) and has 22 indicators, integrating them using their relative weights. The model is applied to evaluate the water security of Wuhan urban agglomeration, China. The values of the indicators are normalized using the exponential efficacy functions based on the law of diminishing marginal utility. The evaluation results show that, overall, the state of water security in Wuhan urban agglomeration is good, which is in good agreement with the true situation. The comparison between the results of the model and other three evaluation methods by the Spearman coefficient of rank correlation verifies the science and reliability of the developed model. Consequently, it is concluded that the model can be an effective tool for evaluating the states of water security and provide a basis on which to create policies for improving inadequacies in water security.

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