The Empirical Study Of The Impact On Aerosol Optical Depth From Urban Pattern Evolution

The expanding scope of construction land in large cities has led to a deterioration in air quality.Controlling of the urban spatial pattern and landscape pattern from the perspective of the city-level of overall urban design is particularly critical to the improvement of urban air quality.In this study,the relationship between construction land cover,construction land use related indicators,vegetation coverage and landscape ecological index in the evolution of spatial pattern is explored to explore the relationship between urban pattern construction and air quality.Using remote sensing data as the basic data analysis object,Wuhan,Nanjing and Chongqing were used as examples to analyze the urban spatial pattern and landscape pattern related indicators of Landsat data through software Envi.Urban aerosol concentration distribution is characterized by aerosol optical thickness(AOD)remote sensing data that has been proven by other scholars to effectively reflect pollutant concentrations.And inversion of MODIS aerosol data was proccessed by software of Envi,combined with Arcgis for spatial data matching and extraction analysis.According to the research purpose of this study,the urban spatial pattern mainly discusses the construction land coverage(CON_cov),the average patch shape index(SHAPE_mn),aggregation index(AI)and maximum plaque index(LPI)in the construction form indicators.In the landscape pattern,the vegetation coverage(VEG_cov),the landscape shape index(LSI),the contagion index(CONTAG),and the Shannon diversity index(SHDI)in the landscape ecological index are mainly discussed.First,the urban pattern indicators and AOD bivariate analysis are used to obtain the correlation coefficient between each index and AOD.The correlation coefficient of density index is the largest,followed by the index of dominance,shape and structure.The average correlation coefficient of the spatial pattern is higher than the landscape pattern.Secondly,in order to avoid the information overlap and interference between the indicators,it need to coped with the principal component analysis of the indicators,and then the multiple regression of AOD,the AOD contribution rate of each index is obtained.The contribution rate of CON_cov in the density index increases year by year,while the contribution rate of VEG_cov decreases year by year.The contribution rate of shape indicators has been decreasing year by year,but the overall contribution rate is higher.Structural indicators maintain a stable and low level of contribution.The dominance index has a higher contribution rate,second only to the density index.The analysis of the contribution rate of the impact factors of the comprehensive average three-city pattern indicators,CON_cov,VEG_cov,LPI,SHAPE_mn,AI,LSI,SHDI,CONTAG AOD urban pattern contribution rate distribution ratio is 23.2%,16.4%,15.8%,12.6%,10.1%,9.6%,7.3%,5.0%.Thirdly,by analyzing the Moran'I variation of local spatial correlation and obtaining spatial heterogeneity based on geographically weighted regression,it can be found that the urban AOD distribution tends to be homogenized,and the contribution of the construction land in the main urban area to the marginal area in aerosol particles is The value is larger and the trend is more pronounced.for the maximum contribution rate of CON_cov,VEG_cov,according to the administrative division analysis of the impact of changes in construction land and vegetation area on AOD,it is found that most of the obvious changes in area occur in the urban marginal administrative area,and the impact on AOD is obvious,and the area of the central city does not change.Obviously,but AOD is still rising,which is related to changes in the nature of land use.Finally,the eight indicators are selected to calculate the higher and lower areas on the distribution map.Compared with the AOD results,the index calculation results,and the plaque characteristics,it is found that the shape fragmentation of the construction land patches and the landscape patches will increase the AOD.The high ductility and high integrity of construction land patches will reduce AOD,and the high ductility and high diversity of landscape patches will increase AOD.The research results can provide relevant theoretical research methods,construction opinions and data support for spatial morphological structure,public space system and landscape structure in overall urban design,and make some suggestions for urban design in air quality management.