Ocean surface foam modeling for passive remote sensing of ocean surface wind vectors

A method of incorporating ocean surface foam into a combined asymmetric wave geometrical optics (AWGO) ocean surface emission model using dielectric mixing theory is investigated. Dielectric mixing represents a more direct method of denying the emissivity of ocean foam within in the AWGO emission model compared with the current AWGO foam emissivity values which are based upon models derived from airborne brightness temperature measurements of ocean foam. Unfortunately, these observations may not reflect the proper sea state or other relevant conditions that are desired within the model. Using dielectric mixing, knowledge of the void fraction within a foam-covered area is used to compute the emission characteristics of a surface facet. This latter technique perhaps will allow better fidelity in ocean foam emission modeling provided that data concerning the bubble density, bubble size distributions, and foam patch locations are well known. Comparison of AWGO model brightness temperatures using the above two methods of modeling foam emissivity illustrate the sensitivity to foam in the computed azimuthal wind direction signatures.