| Several theories and computatign methods for the rough surface scattering ofelectromagnetic wave are introduced and analyzed in this thesis. Then the abnormal radarechoes phenomena -polar mesosphere summer echoes (PMSEs) in polar regionmesopanse is studied based on the random rough surface scattering model. The maincontent of this thesis includes: (1) The major analytic theories which include Kirchhoffapproximation (KA), small perturbation method (SPM) and improved Monte Carloperturbation theory based on SPM are analyzed. (2) The numerical method -Moment ofmethod (MOM) for random rough surface scattering is also analyzed. A method ofintegral by parts is proposed to transfer the singular integral to nonsingular functionintegral in the calculation of rough surface scattering by MOM, it has improved theaccuracy of computation results. (3) The experiment of rough surface scattering when theelectromagnetic wave illuminates on the rough surface is implemented. And a model ofrough paraffin surface is practically made based on the generation method of randomrough surface, Then the scattering characteristic of the model is tested. (4) The abnormalradar echoes phenomena-polar mesosphere summer echoes (PMSEs) in polar region isstudied based on the rough surface scattering. A model of two-layered rough surfacescattering is investigated to simulate the mechanism of PMSEs. It is analyzed that howthe parameters of the background of PMSEs in dust plasma and the observation radarsystem affect the observation of PMSEs and radar scattering cross section. |
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