<title>Aerosol characterization using multispectral MERIS measurements</title>

Abstract

Radiative transfer simulation of the proposed MERIS channels were made for several aerosol types and aerosol optical thicknesses above water surfaces. The Medium Resolution Imaging Spectrometer will be launched onboard the Environmental Satellite in 1998. The model used for the radiative transfer calculations is based on the Matrix-Operator-Method and describes the ocean-atmosphere-system. Atmosphere and ocean properties were varied to study their influence on the retrieval of aerosol properties. Using three different statistic and semi-statistic retrieval methods for the aerosol type and optical thickness, it is shown to which properties these algorithms are most sensitive. For the aerosol retrieval the aerosol path radiances in three channels in the red and near infrared region of the spectrum were interpreted. These channels and their proposed bandwidths are: (lambda) equals 755 nm with (Delta) (lambda) equals 7.5 nm, (lambda) equals 870 nm with (Delta) (lambda) equals 10 nm and (lambda) equals 1022.5 nm with (Delta) (lambda) equals 25 nm. The results show that a crude aerosol characterization in maritime like and continental like aerosols and mixtures of both is possible using the spectral radiances in the three proposed channels. It is also shown how these results are affected by the accuracy of the knowledge about atmospheric and oceanic properties such as surface air pressure, scattering at suspended matter in the ocean and ocean roughness.