Monitoring Of Impervious Surface Based On Remote Sensing And Its Impact On Ecological Environment Quality

Since the 21 st century,China’s economy and society have developed rapidly.With the continuous acceleration of urbanization,the scale of cities has expanded rapidly,and land use methods have changed accordingly.A large number of natural surfaces have been replaced by artificial surfaces,causing damage to the ecological environment.As an important part of the Central Plains urban agglomeration,the Zhengzhou-Kaifeng area has experienced a rapid urbanization process since the country implemented the Central Rise Strategy in 2004.The urban land has continued to expand,and the rapid urban expansion has had a series of impacts on the ecological environment.Dynamic monitoring of urban expansion in this area and analysis of the impact of urban expansion on the quality of the ecological environment will provide a reference for the optimal design and development planning of impervious surfaces in the ZhengzhouKaifeng area,which is of great significance to the sustainable development in the region.In this paper,the urban area of Zhengzhou-Kaifeng and the north of Zhongmu County of Zhengzhou are the research areas,and Landsat-5 and Landsat-8 remote sensing images are used as data sources.The spatial and temporal distribution pattern and dynamic change law of impervious surface in the area;meanwhile,a remote sensing ecological index(RSEI)was constructed based on greenness index(NDVI),humidity index(WET),dryness index(NDBSI),and heat index(LST).The RSEI model quantitatively analyzes the temporal change trend and spatial distribution characteristics of the regional ecological environment quality.Finally,the impact of impervious surface expansion on the ecological environment quality is analyzed based on different scales.The main findings are as follows:(1)From 2004 to 2020,the impervious surface in the Zhengzhou-Kaifeng area expanded rapidly and intensely,and the expansion direction was consistent with the direction of the main traffic axis.From 2004 to 2020,the growth rate of impervious surface area was 164%.In 2004,the impervious surface area was 494.75km2,and in 2020,the impervious surface area was 1309.26km2;the impervious surface coverage increased from 20.04% in 2004 to 53.04% in 2020.From 2004 to 2020,the expansion speed and expansion intensity of the Zhengzhou-Kaifeng impervious surface showed a downward trend,and a sharp decline occurred in 2015.The Zhengzhou-Kaifeng impervious surface has gone through three stages of urban inner filling,outward expansion,and inner filling to connect plaques.The impervious surface mainly expands in the east-west direction.The distribution directions of impervious surfaces in Zhengzhou and Kaifeng are the same as the main traffic axes.There is a strong link between relevant government policies,population growth,economic development,the distribution of transportation routes and the expansion of impervious surfaces.(2)From 2004 to 2020,the overall quality of the ecological environment in ZhengzhouKaifeng area was at a moderate level,and the quality of the ecological environment showed a downward trend during this period.From 2004 to 2020,the mean values of RSEI in Zhengzhou-Kaifeng area were0.64,0.46,0.54,and 0.49,respectively.Through the principal component analysis of the four indicators for constructing RSEI,it can be seen that NDVI and WET have a positive impact on RSEI,while NDBSI and LST have a positive impact on RSEI.Has a negative impact on RSEI.On the spatial scale,the ecological environment quality of Zhengzhou is poor,and the ecological environment quality of Kaifeng is better.Among the districts(counties),the ecological environment quality of Jinshui District,Zhongyuan District and Guancheng Hui District is poor,and the ecological environment quality of Shunhe Hui District is better.Urban development intensity and land use changes are important factors that affect the quality of the ecological environment.After 16 years of development in the Zhengzhou-Kaifeng area,the quality of the ecological environment has deteriorated significantly,and it is widely distributed,mainly concentrated in areas outside the third ring road of Zhengzhou,Most of the Longting District of Kaifeng City,the western part of Shunhe Hui District,the western part of Yuwangtai District,and the northern part of Zhongmu County along the Yellow River.(3)RSEI was affected by impervious surface coverage,and there was a significant negative spatial correlation between the two.Based on the 1000m×1000m grid,the street(township),and district(county)scales,the correlation analysis between the impervious surface coverage and RSEI from 2004 to2020 was carried out,and there was a significant negative relationship between the impervious surface coverage and the mean value of RSEI.Correlation relationship,which shows that with the expansion of impervious surface,the ecological environment quality in the region is continuously declining.Bivariate global spatial autocorrelation and bivariate local spatial autocorrelation analysis both showed that there was a negative spatial correlation between impervious surface coverage and RSEI,and H-L(high impervious surface coverage-low RSEI)agglomeration areas were mainly distributed in Within the Second Ring Road of Zhengzhou City and the old city of Kaifeng City.Through the analysis of the center of gravity,it can be seen that the center of gravity of the impervious surface expansion area in Zhengzhou and Kaifeng and the center of gravity of the ecological environment change are in the same area,and the moving directions are basically similar,which further proves that the expansion of the impervious surface affects the quality of the ecological environment..