Salinity, Temperature and Polarization Effects on Top of Atmosphere Radiance's for Case One Waters Using a Simple but Realistic Bio Optical Model and Full Radiative Transfer Solutions
Abstract
Salinity, temperature and polarization have non negligible effects on water leaving radiance's for pure and case one waters. The salinity and temperature of the ocean body has an impact on the refractive index, the bulk scattering coefficient and the absorption coefficient of the sea water. In addition these are specially dependent and we use the channels of the satellite ocean color instruments MERIS and the upcoming OLCI instrument to discuss the effects. The changes in top of atmosphere radiance's caused by changes in temperature and salinity are spectral dependent and depend on viewing geometry also. For the clearest waters these effects are in the order of two to six percent and can be reduced to the order of one percent by increased chlorophyll concentration. We present our new simple but realistic bio optical model used in our full polarized radiative transfer model. The model relates the oceanic chlorophyll concentration to scattering matrices and absorption coefficients for the chlorophyll and colored dissolved organic matter. We discuss the model's advantages and limitations and its relation to other models. Polarization has impact in this scheme if it is neglected in the radiative transfer and that the polarization parameters and the degree of polarization caries information about the state of the ocean. The effects of neglecting polarization depend strongly on direction and wavelength and can reach values of six percent. Hence salinity, temperature and polarization can have impacts of similar magnitude on top of atmosphere radiance's. The degree of polarization is sensitive to chlorophyll concentration and salinity but may also be an issue for radiance sensors showing probably unknown dependencies with respect to polarization. We can conclude that all three parameters can lead to non negligible effects on top of atmosphere radiance's and hence ocean color retrieval schemes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMOS34A..04H
- Keywords:
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- 4200 OCEANOGRAPHY: GENERAL;
- 4264 OCEANOGRAPHY: GENERAL / Ocean optics;
- 4271 OCEANOGRAPHY: GENERAL / Physical and chemical properties of seawater;
- 4275 OCEANOGRAPHY: GENERAL / Remote sensing and electromagnetic processes