Spatial And Temporal Correlation Between Urbanization And PM2.5 Based On Noctilucent Data

With the evolution of the level of urbanization,urban residents also have more urgent practical needs for the quality of urban living,education and ecological environment.It is pointed out in the report of national environmental air quality standard that PM2.5 is an important component of air pollution.Therefore,the study on the influence mechanism of the spatial and temporal distribution change of PM2.5 concentration caused by urbanization development and the characteristics of the spatial and temporal correlation between the two have gradually attracted more and more attention.With the rapid development of luminous remote sensing and geographic information system(GIS)technologies,relevant studies have gradually realized the monitoring of the urbanization development and temporal changes of patterns at different spatial scales,making the research more simple,accurate and efficient.Based on the existing research framework at home and abroad,this paper uses multi-source noctilucent images to realize the identification,dynamic monitoring of development and spatial pattern change monitoring of urban built-up areas on different spatial scales based on night light images,so as to explore the relationship between night light brightness and urbanization level.On this basis,the correlation between night light image data and PM2.5 grid data is analyzed by relevant mathematical analysis model,so as to explore and analyze the spatial-temporal correlation characteristics between urbanization and PM2.5 concentration.The main contents are as follows:(1)From the perspective of spatial region,the spatial pattern distribution and sequential change of built-up areas in cities and towns of Jiangxi province were explored.Combining DMSP/OLS,NPP/VIIRS two night lighting image data,realize the 11 cities in Jiangxi province,1995-2017 the extraction of urban area,to analyze its spatial structure and temporal variation characteristics,found in Jiangxi province town core in space presents "south dredge north close,a small" form,and urban area is present on the space "first party after,continuous expansion" in the overall spatial pattern;In addition,the built-up areas of all cities within the region show a trend of double speed growth,with significant urbanization development characteristics.(2)The DMSP/OLS and NPP/VIIRS images were accurately identified and extracted from the study areas of Jiangxi province from 1995 to 2017 by using the statistical information based dichotomy iteration method combined with relevant authoritative statistical data.By using this method,the dynamic changes of Jiangxi province and its 11 cities and towns were studied,and it was found that Jiangxi province initially formed a "point-axis" spatial pattern of provincial towns with Nanchang as the center,Nanchang-Jiujiang,Nanchang-Yichun and Nanchang-Fuzhou.(3)Using the PM2.5 grid data of long time series at the county scale of Jiangxi Province,the PM2.5 concentration levels of all counties and regions in Jiangxi province from 1998 to 2017 were monitored dynamically,compared spatio-temporal differences and predicted in the future.The study shows that the PM2.5 concentration in Jiangxi province presents a development trend of "high in the north and low in the south,rising first and then falling later".The high PM2.5 concentration is mainly found in Nanchang and Jiujiang in northern Jiangxi.The change trend shows a rapid growth trend from 1998 to 2013,and a downward trend after 2013.(4)Ordinary linear regression,geographical weighted regression and other mathematical analysis models were used to analyze multiple types of urbanization level index,the night light intensity index and the annual mean value of PM2.5,so as to study and analyze the spatio-temporal correlation characteristics between urbanization and PM2.5 in Jiangxi Province.The study shows that in terms of spatial distribution,the correlation between PM2.5 and most areas in northern Jiangxi province is positively correlated,and most areas with significant growth and change are concentrated around Jiujiang and Nanchang city;while in southern Jiangxi,the overall correlation coefficient is small,and the air quality change is relatively insignificant.