Study Of Electromagnetic Scattering From Ocean Random Rough Surfaces

Being the essential part of remote sensing instrument design, ocean parameter inversion prob-lems, composite model scattering prediction, etc., calculation of electromagnetic scattering from ocean random rough surface has been paid plenty of attention during the past decades. This dis-sertation focused on high accurate and efficient1D full range ocean random rough surface electro-magnetic scattering problems. Based on the GMRES-RP combined with advanced SA technology, the contribution of different scales of ocean random surface was analyzed. And also the accuracy and applicability of analytical models were verified by numerical calculations.First of all, the original SA of GMRES-RP was modified and advanced to fit the high effi-ciency requirement of ocean rough surface with extremely large rms height. Then GMRES-RP was applied to a systematic analysis of the scattering properties with varies sensor parameters and seacondition. More refined structures were found at the incidence angle of20°than suggested in the literature. Also the contribution of intermediate-scale waves at transient incidence was vali-dated by changing the degree of intermediate and large scale waves included in the simulation. Further the necessity of advancing multi-scale models beyond the conventional two-scale model was indicated by a comparison of the two-scale model and three-scale model against numerical results where the two-scale model shows appreciable discrepancy in the forward scattering angles whereas the three scale model shows very good agreement with MoM. This study also implies the need for numerical studies to use adequately large surface length, at least to cover the intermediate waves, even for below intermediate incidence cases.Secondly, a three-scale model with fully determined analytical form was proposed and the va-lidity of two-scale model and this three-scale model was systematically studied based on GMRES-RP in a wide range sensor parameters and seacondition. It was found that the accuracy of two-scale model with numerical integrated KA performed better on bistatic scattering prediction than that with GO, nevertheless it failed at certain case anyhow, while the three-scale model demonstrated a wider range of application. Thirdly, the PEC assumption, considered to be reasonable in active remote sensing for ocean scattering in literature was found inappropriate for VV polarization scattering prediction. Also the accuracy of IBC was evaluated referring to the results of strict single dense grid two layer numerical simulation.Lastly, WCA model was incorporated into the newly proposed OMC method as alternative initial value, which further improved the efficiency of HH polarization calculation remarkably.