Utilization of MERSI and MODIS data to monitor PM2.5 concentration in Beijing-Tianjin-Hebei and its surrounding areas

Abstract

Beijing-Tianjin-Hebei and its surrounding areas are some of the most PM2.5-polluted regions in China. Satellite remote sensing technology is an advanced and important means for monitoring the change in spatio-temporal distribution of large-range PM2.5. In this study, we conduct AOT retrieval and validation analysis based on the Dark Target (DT) Method by utilizing FY-3B/MERSI and AQUA/MODIS satellite data in this region. The weather and ground observation data are brought in to retrieve the regional PM2.5 concentration using the GWR model, and cross-verification assessment for remote sensing and retrieval results is conducted. Through comprehensive comparison, this study analyzes the capability of MERSI and MODIS in monitoring aerosol and PM2.5. Finally, a preliminary exploration analysis on the monthly temporal and spatial changing status of PM2.5 concentration is conducted in the first quarter of 2017 in Beijing-Tianjin-Hebei and its surrounding areas by utilizing MERSI data. Results show that the remote sensing monitoring capability of FY-3B/MERSI is slightly better than that of AQUA/MODIS. The R2 between AOT and PM2.5 dataset with a resolution of 1 km retrieved from MERSI and that from the ground station observation results are 0.76 and 0.79, respectively. The root-mean-square errors are 0.26 and 28 μg/m3, respectively, while the mean absolute errors are 0.16 and 15 μg/m3, respectively. The results can basically meet the demand of fine PM2.5 monitoring in Beijing-Tianjin-Hebei and its surrounding areas. The remote sensing monitoring results of monthly PM2.5 concentration in the first quarter of 2017 in Beijing-Tianjin-Hebei and its surrounding areas show that the spatial pattern of PM2.5 is closely related to the terrain and landscape, with the high concentration zone mainly lying along the Taihang mountains in flakes. From the view of temporal change, a decreasing trend is noted, with March seeing a plunge in concentration value compared with the first two months. The findings suggest that FY-3B/MERSI remote sensing retrieval results can provide effective reference for environmental quality monitoring and environmental management effectiveness evaluation. This study is significant for the development of domestic satellite application in atmospheric environmental remote sensing sector.