The GO4 Model in Near-Nadir Microwave Scattering From the Sea Surface

The GO4 Model in Near-Nadir Microwave Scattering From the Sea Surface

We introduce a practical and accurate model, referred to as "GO4," to describe near-nadir microwave scattering from the sea surface, and at the same time, we address the issue of the filtered mean square slope (mss) conventionally used in the geometrical optics model. GO4 is a simple corre...

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Bibliographic Details
Published in:IEEE transactions on geoscience and remote sensing Vol. 53; no. 11; pp. 5889 - 5900
Main Authors: Boisot, Olivier, Nouguier, Fredric, Chapron, Bertrand, Guerin, Charles-Antoine
Format: Journal Article
Language:English
Published: IEEE 01-11-2015
Institute of Electrical and Electronics Engineers
Subjects:
Approximation methods
Curvature
General Physics
geometrical optics
near-nadir
ocean radar sensing
Optical surface waves
Physics
Radar
Scattering
Sea surface
slope
Surface waves
Wind speed
near-nadir
geometrical optics
slope
Curvature
ocean radar sensing
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Summary:We introduce a practical and accurate model, referred to as "GO4," to describe near-nadir microwave scattering from the sea surface, and at the same time, we address the issue of the filtered mean square slope (mss) conventionally used in the geometrical optics model. GO4 is a simple correction of this last model, taking into account the diffraction correction induced by the rough surface through what we call an effective mean square curvature (msc). We evaluate the effective msc as a function of the surface wavenumber spectrum and the radar frequency and show that GO4 reaches the same accuracy as the physical optics model in a wide range of incidence and frequency bands with the sole knowledge of the mss and msc parameters. The key point is that the mss entering in GO4 is not the filtered but the total slope. We provide estimation of the effective msc on the basis of classical sea spectrum models. We also evaluate the effective msc from near-nadir satellite data in various bands and show that it is consistent with model predictions. Non-Gaussian effects are discussed and shown to be incorporated in the effective msc. We give some applications of the method, namely, the estimation of the total sea surface mss and the recalibration of relative radar cross sections.
ISSN:0196-2892
1558-0644
DOI:10.1109/TGRS.2015.2424714