SIMULATION OF REMOTE-SENSING OF SEA-SURFACE TEMPERATURE FROM SPACE - INFLUENCES OF CIRRUS CLOUDS AND STRATOSPHERIC AEROSOLS ON SEA-SURFACE TEMPERATURES DERIVED FROM THE VISSR-ATMOSPHERIC-SOUNDER

This simulation study demonstrates that cirrus clouds and volcanic aerosols with atmospheric gases would greatly affect the transmission functions and brightness temperatures of infrared window channels in the VISSR Atmospheric Sounder (VAS), and VAS-derived sea surface temperature (SST) determinations. The 'clear air' (CLR) retrieval equations should not be used in the presence of cirrus and high stratospheric aerosol loadings. An alternative five-window channel algorithm could be found that would work in arbitrary clear, cirrus or aerosol conditions, but the retrieval accuracy would decrease in comparison with the multi-channel SST (MCSST) algorithms for simply cirrus clouds, or aerosols only. In MCSST algorithms, channel 12 (3.94 mu m) is most important for CLR, or tenuous cirrus with any kind of aerosols, or moderate cirrus with weak aerosols, whereas for moderate cirrus combined with the strong aerosol, or dense cirrus with any kind of aerosols, channel 5 (13.34 mu m) or channel 8 (11.22 mu m) becomes the most important. In addition, the effects of variations of water vapour profile, aerosol concentration, and sea surface reflection (SSR) on SST retrievals need to be considered.