Estimation Of The Relationship Between Satellite AOD And PM_2.5 And Analysis Of The Distant Source Transport Trajectory Based On Aerosol Vertical Information

Ground air pollution monitoring is mainly the dispersed points monitoring.But limited stations can't reflect the distribution of aerosol particles in space.Satellite remote sensing can make up for the deficiency of the ground monitoring sites.Using the remote sensing aerosol optical depth data to retrieve the ground particle concentration,which is affected significantly by the seasonal variation of atmospheric environment and the aerosol vertical variation.This paper applicats the vertical variation of aerosol profiles information by lidar from 2013 to 2015 3 years in Wuxi area,to correct the MODIS AOD data of fine,pollution and aerosol input weather,and establish the estimation model of MODIS AOD and ground PM2.5 concentration.In addition,based to the different atmospheric environment 0.3⁰.5km,0.5¹.0km,1.0².0km and 2.0³.0km aerosol optical thickness data calculated by lidar,to analyse the fine,pollution,input and transit input weather different heights aerosol extinction changes.Combined with HYSPLIT backward trajectory model of transport route determines the main source,transmission route and the impact on local pollution of foreign input pollutants in Wuxi area.Analysis results show that:?1?The estimation model correlation and accuracy of MODIS AOD and PM2.5 corrected by extinction profiles was higher than that of the direct method and the aerosol elevation corrected model.Considering the extinction profiles vertical variation of different atmospheric,it can reduce the influence of estimation the relationship between MODIS AOD and PM2.5 by aerosol extinction vertical variation that caused by input layer and pollution weather accumulation,which has important significance for monitoring the concentration of ground particles using satellite remote sensing data.By MODIS AOD and PM2.5 data in winter sunny weather,the spring weather pollution and summer weather pollution and autumn weather pollution,does not have the correlation at 0.05 level of significance test showed that the ground air relative humidity,wind speed and other factors have an important influence on the relationship estimation between PM2.5 and AOD.?2?The different atmosphere conditions AOD0.3⁰.5km,AOD0.5¹.0km,AOD1.0².0km and AOD2.0³.0km calculated by lidar seasonal variation are given quantitatively.Comparative analysis of 500 nm band fine mode optical thickness ratio inversion by CE-318 "FineModeFraction₅00nm" and MODIS retrieved land fine mode optical thickness ratio "Optical_Depth_Ratio_Small_Land" data,combined with the extinction coefficient and depolarization ratio by lidar,display that land fine mode optical thickness ratio data by MODIS is more sensitive on the upper layer aerosol size change,and the fine mode optical thickness ratio data by CE-318 is more sensitive to the change of the near surface layer aerosol size.Comparison of the ground PM2.5 and MODIS AOD data in fine weather,the relationship between PM2.5 and MODIS AOD is affected by the seasonal variation of atmospheric stratification stability,and the seasonal variation of aerosol particle size and relative humidity is also an important factor affecting AOD value.?3?Input trajectory of high pollution layer and near the ground 500 m trajectory has significant difference.Near ground air trajectory were significantly affected by winter monsoon circulation influence,and there is a wide range of northern cold high distance input.By summer monsoon climate,the airflow mainly came from the east and south direction of the sea.Spring and summer are jointly affected by the East Asian winter monsoon circulation and the summer monsoon circulation,affected by the cold air from the north and the East sea influence.The main source of pollution contribution to the near surface of Wuxi is the short distance horizontal flow.The input trajectory of the upper layer is mainly from the northwest of China,and the direction of input air flow is more dispersed in summer.