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

摘要

This study reports on the potential of MERISrnmeasurements for estimating the aerosol layer altitudernover ocean. Characteristics of the MERIS instrumentrnonboard ENVISAT allow aerosol altitude retrievalsrnusing a two-band ratio method in the oxygen absorptionrnA-band. An algorithm is presented for aerosol altitudernretrievals using MERIS data. This altitude retrievalrnmodule is a part of the ALAMO algorithm, developedrnby HYGEOS for the characterization of aerosols overrnocean using MERIS. For this task, data have beenrnprocessed by the ICARE Data and Services Centre.rnResults and accuracy are discussed as a function of thernaerosol optical thickness, especially for aerosol plumesrnover Atlantic Ocean or polluted areas. Comparisonsrnbetween MERIS retrievals and altitudes derived fromrnthe Cloud-Aerosol Lidar CALIOP (A-train) arernpresented for quasi-simultaneous observations and showrnagreements at local and global scales.