Retrieval of Atmospheric and Marine Parameters in Coastal and Inland Aquatic Environments from Geostationary Platforms: Challenges and Opportunities

Simultaneous retrieval of aerosol and surface properties by means of inverse techniques based on a coupled atmosphere-surface radiative transfer model (CRTM) and optimal estimation can yield a considerable improvement in retrieval accuracy in complex aquatic environments compared with traditional methods. Remote sensing of such environments represent specific challenges due (i) the complexity of the atmosphere and water inherent optical properties, (ii) unique bidirectional dependencies of the water-leaving radiance, and (iii) the desire to do retrievals for large solar zenith and viewing angles. We will discuss (a) how challenges related to atmospheric gaseous absorption, absorbing aerosols, and turbid waters can be addressed by using a CRTM forward model in the retrieval process, (b) how the need to correct for bidirectional effects can be accommodated in a systematic and reliable manner, and (c) how the curvature of the atmosphere can be taken into account. Special emphasis will be placed on how information from existing and future sensors deployed on geostationary platforms can be obtained in a reliable and accurate manner. Thus, the need to provide uncertainty assessments and error budget will also be discussed.