Information content of measurements in the O2A- and O2B-bands for monitoring of aerosols from space

摘要

Abstract: The information content of radiance measurements in the O$-2$/A- and O$-2$/B-bands over the oceans for aerosol monitoring from space is discussed. A simple model of radiation transfer in the system atmosphere/ocean shall be used for estimation of optical thicknesses of different aerosol layers and ocean reflection. There are 3 nonredundant spectrometer channels in the O$-2$/A- band around 762 nm and 2 nonredundant channels in the O$-2$/B- band around 687 nm. High measurement accuracy of about 1% is more important for the measurements than a halfwidth $Delta$lambda$- FWHM$/ of spectrometer channels smaller than 1 nm. A sensitivity analysis shows that the optical thickness of stratospheric aerosols can be estimated from measurements in the O$-2$/A- and O$-2$/B-bands. From these results the chance to use combined measurements in both bands for distinction between volcanic and background-stratospheric aerosols exists. There also is a chance to use measurements in the O$-2$/A-band for estimation of the optical thickness of aerosols in the free troposphere. The estimation of the optical thickness of aerosols within the maritime boundary layer can be expected from measurements in the O$-2$/A-band, if ocean reflection is known. To estimate optical thicknesses of different aerosol layers is not only useful for aerosol studies, but also for better atmospheric correction of satellite images of the ocean surface. !18