The 5S-like formulation of the signal in the O-2-A band: application to cloud detection

摘要

When clouds cannot be detected by a radiometry approach, the O-2-A absorption band, located around 762 nm, can be used under clear sky conditions to perform this task. We present in this article a 5S-like formalism for the O-2 band, based on single scattering approximation, aiming to isolate the aerosol contribution. The apparent pressure of the aerosols layer, derived from this new formalism, is used in the processing chain for the Medium Resolution Imaging Spectrometer (MERIS; on-board the ENVISAT platform) third processing to detect the presence of cirrus clouds over water. This formalism can be used as well over land to correct surface pressure, derived from the O-2-A band, from the influence of the atmosphere.