Salinity and Temperature Effects on Top of Atmosphere Radiances for Case One Waters Using a Simple But Realistic Bio Optical Model Andr´ e Hollstein, J¨ urgen Fischer October 4, 2011 Abstract We describe our simple but realistic bio optical model which relates oceanic chloro- phyll concentration to scattering matrices and absorption coefficients for chlorophyll and colored dissolved organic matter (CDOM). The model itself, its advantages and limitations and its relation to other models is discussed in detail in section 1. In sec- tion 2 we discuss the effects of salinity and temperature to top of atmosphere radiance and water leaving radiance for the 11 OLCI channels from 412.5nm to 761.25nm. In the spectral region where the water bulk contributes to the top of atmosphere signal the effects of salinity and temperature are reduced roughly by a factor of 5. The importance of the chlorophyll concentration for top of atmosphere radiance decreases with increasing wavelength since the water bulk becomes more and more black and the rough ocean surface is dominating the salinity and temperature effects. We discuss two main effects of polarization in section 4. First the effects of neglecting polarization in the radiative transfer scheme and then the results for the top of atmosphere degree of polarization and their sensitivity to chlorophyll concentration and salinity changes. The effects of neglecting polarization depend strongly on direction and wavelength and can reach values of ±6%. The degree of polarization is also carrying information since it is sensitive to chlorophyll concentration and salinity but may also be an issue for radiance sensors showing probably unknown dependencies with respect to polar- ization. To extend the study to the complete 400nm to 1020nm wavelength regime we relied on a much simpler bio optical model which is based on a single chlorophyll absorption spectrum and a model for the concentration dependency. Using these re- sults we show results for all covered OLCI channels and discuss the polarization effects in 400nm channel in more detail. For both the top of atmosphere radiance and the water leaving radiance we discuss the error’s if only scalar radiative transfer is used. In our discussion we neglect the effects of Raman scattering but include a discussion in section 7. 1