| In recent years,in the context of rapid urbanization,as the frontier of China’s coastal opening up and an important starting point for the “One Belt One Road”initiative,the Guangdong-Hong Kong-Macao Greater Bay Area has become one of the fastest-growing urban agglomerations in my country.Its urbanization development status and ecology Environmental quality has attracted much attention at home and abroad.The impervious surface is one of the important indicators reflecting the degree of urbanization.Monitoring and analyzing the temporal and spatial dynamics of impervious surfaces and their impact on the ecological environment can not only increase the understanding of the urbanization process of the Greater Bay Area,but also have important practical significance for the future urban development planning of the Greater Bay Area.This study is based on Landsat TM,OLI remote sensing image data and land use classification data,using an object-oriented method to obtain the impervious surface information of the Guangdong-Hong Kong-Macao Greater Bay Area from 1990 to 2020.Using geographic information system technology(GIS),staring from the temporal and spatial evolution characteristics of the impervious surface in the Greater Bay Area based on the characteristics of time and space,combined with the changes of the surface characteristics index.Use the quadrant azimuth analysis method to explore the expansion mode of the impervious surface,and combine statistical data to explore the driving factors of impervious surface expansion from the perspectives of economy,population and policy.Based on the RSEI model to analyze the characteristics of the spatial and temporal changes of the ecological environment quality in the Greater Bay Area over the past 30 years,and discuss the impact of the temporal and spatial evolution of the impervious surface on the urban ecological quality from the perspectives of the proportion of impervious surface area and the spatial distribution pattern of impervious surface Impact.The main conclusions are as follows:(1)The expansion of the impervious surface of the Guangdong-Hong Kong-Macao Greater Bay Area was mainly concentrated in 1990-2010.Since 2010,the expansion speed and intensity of the impervious surface of the Greater Bay Area have dropped sharply,and the expansion of the impervious surface of the Greater Bay Area has gradually entered a stagnant stage.In the past 30 years,the expansion speed and expansion intensity of the impervious surface of the Greater Bay Area have shown a trend of first increasing and then decreasing,and both indicators have obvious unimodal characteristics.The expansion of impervious surfaces in the Greater Bay Area occupies the largest area of arable land(61.94%),followed by forest land(24.34%)and wetland(12.24%).The center of gravity of the impervious surface of the Guangdong-Hong Kong-Macao Greater Bay Area mainly migrates along the southeast-southwest-northwest trajectory,and the impervious surface mainly expands east-west.The expansion of impervious surfaces in cities in the Greater Bay Area is dominated by jump-type cluster expansion and belt-like expansion along the traffic axis.Population growth,economic development and relevant government policies are closely related to the expansion of impervious surfaces in cities in the Pearl River Delta.There are certain differences in the development of cities in the Greater Bay Area: Hong Kong and Macau Special Administrative Regions started early due to urbanization and relatively complete urban construction.The GDP growth rate far exceeds the expansion rate of impervious surface.(2)From 1990 to 2020,the overall ecological environmental quality of the Guangdong-Hong Kong-Macao Greater Bay Area was at a good level.During this period,the ecological environmental quality showed a general trend of first decline and then increase.On the spatial scale,the distribution of ecological environment quality in the Greater Bay Area has obvious spatial heterogeneity,which is mainly presenting a distribution pattern of poor ecological environment quality in urban agglomeration areas in the central plain,and good ecological environment quality in the eastern and western hilly areas.The area where the ecological environment quality of the Greater Bay Area has not changed significantly in the past 30 years accounted for the highest area,52.20%;the area where the ecological environment was relatively deteriorating accounted for 29.75%;the area where the ecological environment was relatively better accounted for the smallest area,which was 18.05%.Cities where the quality of the ecological environment in the Greater Bay Area has significantly deteriorated include Macau Special Administrative Region,Zhongshan,Guangzhou,Dongguan,Zhuhai and Foshan;cities where the quality of the ecological environment has improved include Hong Kong Special Administrative Region,Huizhou and Zhaoqing;there is no significant change in the quality of the ecological environment The cities include Shenzhen and Jiangmen.(3)From 1990 to 2020,the proportion of impervious surface area in the Guangdong-Hong Kong-Macao Greater Bay Area increased significantly.The RSEI mean of the impervious surface area dropped from 0.58 in 1990 to 0.50 in 2020,which was 11.09% higher than the overall RSEI decline in the study area during the same period.It is the main location for changes in the quality of the urban ecological environment in the Greater Bay Area.The RSEI mean decreases with the increase in the percentage of impervious surface area.High-density impervious surface area has a greater negative impact on the ecological environment than low-density impervious surface area.The ecological environment quality of areas with high impervious surface area is relatively high.Poor.There is a strong correlation between the quality of urban ecological environment and the degree of aggregation,average proximity and average patch area of impervious surface patches.The area of impervious surface patches is small,the degree of aggregation is low,and the connectivity between patches is poor.The quality of the ecological environment in urban areas is better than that of urban areas with large impervious patches and densely distributed areas.In the future urban development of the Greater Bay Area,attention should be paid to the balance between the central and east and west wings,further control the proportion of impervious surface,optimize the spatial distribution pattern of impervious surface patches and the proportion of green space within the city,and increase the amount of green space in the city.Construction to improve the overall greening service function of the city. |
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