ESTIMATING AEROSOL ALTITUDE OVER OCEAN FROM O2 A-BAND ABSORPTION USING MERIS OBSERVATIONS

摘要

This study reports on the potential of MERIS measurements for estimating the aerosol layer altitude over ocean. Characteristics of the MERIS instrument onboard ENVISAT allow aerosol altitude retrievals using a two-band ratio method in the oxygen absorption A-band. An algorithm is presented for aerosol altitude retrievals using MERIS data. This altitude retrieval module is a part of the ALAMO algorithm, developed by HYGEOS for the characterization of aerosols over ocean using MERIS. For this task, data have been processed by the ICARE Data and Services Centre. Results and accuracy are discussed as a function of the aerosol optical thickness, especially for aerosol plumes over Atlantic Ocean or polluted areas. Comparisons between MERIS retrievals and altitudes derived from the Cloud-Aerosol Lidar CALIOP (A-train) are presented for quasi-simultaneous observations and show agreements at local and global scales.