Aerosol information acquisition from MODIS sensor and accuracy assessments in the Yangtze Delta region of China in 2008

Abstract

The Moderate Resolution Imaging Spectroradiometer (MODIS) onboard EOS Terra measures global aerosol optical depth (AOD) and optical properties since 2000. MODIS aerosol products are freely available and are being used for numerous studies. However, the retrieval quality of the MODIS aerosol products in different regions is the international research hotpot. The purpose of this study is to retrieve AOD in the Yangtze Delta region and evaluate the accuracy of retrievals, furthermore analyze the dynamics of AOD in different regions. In this paper, firstly, we introduced the principle of aerosol information acquisition from MODIS sensor and retrieval algorithm. Secondly, we present a comparison of AOD retrieved from MODIS with Aerosol Robotic Network (AERONET) data for the year 2008 over four different sites of the Yangtze Delta region, a well-industrial region lying in East Coast of China. AOD retrieved from MODIS at 0.55μm wavelength has been compared with the AERONET derived AOD, within an optimum result. The accuracy of AOD retrieved from MODIS is the best in Lin'an (correlation coefficient R2 is 0.928), the lowest in Hangzhou (R2 is 0.859). The correlation coefficient R2 of Qiandaohu and Tianmu Mountain are 0.881 and 0.869. The reasons of the retrieval error in AOD are found to be the different underlying surface reflectance and aerosol models. Therefore, the aerosol models and underlying surface reflectance are the dominant factors which influence the accuracy of MODIS retrieval performance. In addition, the correction of humidity is important to improve the retrieval accuracy.