Variability of Fresnel surface emissivity of Persian Gulf water in a nadir-viewing direction at C- band

The knowledge of the sea surface emissivity can be used to design passive and active microwave sensors for ocean remote sensing applications. In this study, the variability of vertical and horizontal polarizations of Fresnel emissivity over the Persian Gulf water at 5 GHz in a nadir-viewing direction are investigated by using Fresnel's equations. Data sets used to compute Fresnel reflection coefficients were provided from our previous studies on hydrodynamic and electromagnetic properties of Persian Gulf water. The calculations indicated that spatial variability of Fresnel emissivity for both vertical and horizontal polarizations were relatively large compared to its temporal variability. The annual domain-averaged mean for vertical emissivity at the C- band was 0.3914, whereas for the horizontal polarization of the emissivity, it was 0.3645 in a nadir-viewing direction.