Aerosol retrieval at South China sea by AVHRR image

Abstract

Aerosol Optical Thickness, AOT is one of the factors on determining air quality. The concentration of atmospheric aerosol is determined from radiances of image taken. On this study, we use AVHRR image which is appropriate to retrieve AOT from a wide coverage area. The methods of retrieving aerosol from visible and near-infrared radiance data were applied. The algorithm for mapping was based on dark target method using path radiance and contrast reduction method using atmospheric transmission. Besides, discussion on the level-1B of AVHRR image was also done on preprocessing for calibration and geometrical correction. Satellite and solar geometrical effects would be studied. Besides the environmental factors and distribution of aerosol particles would also be considered in the algorithm. Comparison between aerosol optical derived from each method would be compared with data from MODIS Aerosol Product available online. Regression analysis was performed to find the correlation between these two set of data Graphs of radiance measured at visible channel and AOT was generated by the algorithm to show the relationship between these variables. The look-up table could be used to retrieved the aerosol optical thickness with the sufficient input. ©2008 IEEE.