Aerosol Optical Depth Inversion And Accuracy Evaluation Based On Multi-source Observation Data

In recent years,with the rapid development of China's economy,the air quality has drastically decreased,which has caused people's great attention.Among them,atmospheric pollutants are one of the major causes of air quality degradation.Therefore,the monitoring and analysis of atmospheric pollutants is important.Owing to ground monitoring is unable to monitor aerosols regionally,but the satellite monitoring can make up for the weakness of ground monitoring to realize the spatial continuity of aerosol observations.However,the existing single satellite data has the problem of mutual limitation of temporal and spatial resolution,and it is difficult to achieve temporal continuity for higher spatial resolution data.Therefore,in order to obtain a time series of aerosol optical depth with higher accuracy,the purpose of this thesis is to solve the problem of remote sensing data sources in inversion of aerosol optical depth,via comparing and verifying the accuracy of aerosol optical depth from single remote sensing data and multi-source observation data.On this basis,the main contents and corresponding results of this thesis are as follows:(1)Via comparing the advantages and disadvantages of each fusion algorithm,this thesis chose the CDSTARFM temporal-spatial fusion model which can truly express the surface information,then select the temporal-spatial fusion dataset as one of the data sources for aerosol optical depth inversion.(2)The construction of look-up table is an important part of inverting the aerosol optical depth,in order to ensure the accuracy of look-up table,combining the geographical characteristics of the study area and the type of underlying surface,the sensitivity of 6S model has been analyzed for each of the four study areas.Based on the analysis results,the aerosol type of the four research areas are all set as continental aerosol type.(3)Combining with the AEROENT aerosol observation data,the aerosol optical depth inversion results of MODIS and Landsat8 data have been compared and verified.The result shows that: The inversion accuracy of Landsat8 data is better than that of MODIS,and the improvement of spatial resolution is conducive to improving the inversion accuracy of aerosol optical depth in urban surface areas.(4)The aerosol optical depth inversion accuracy of temporal-spatial fusion data is evaluated based on the AERONET aerosol observation data,and the applicability of temporalspatial fusion data in inversion of aerosol optical depth is explored.The experiment result shows that under the assumptions of CDSTARFM temporal-spatial fusion model and traditional dark target algorithm,the high temporal-spatial fusion data obtained from the urban surface area with low vegetation coverage can be used for aerosol optical depth inversion,which is better than MODIS data.Otherwise,the inversion results of temporal-spatial fusion data of Beijing_CAMS stations in different seasons are compared and verified,the conclusion is that the aerosol optical depth inversion results of temporal-spatial fusion data over Spring and Autumn are better than Summer and Winter.