Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces

Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces

Bibliographic Details
Main Author: Pan, Guangdong
Language:English
Published: The Ohio State University / OhioLINK 2008
Subjects:
Electrical Engineering
Electromagnetism
electromagnetic scattering
radar modulation transfer function
hydrodynamic modulation transfer function
third-scale effect
Doppler
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=osu1204559229
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-osu12045592292021-08-03T05:53:19Z Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces Pan, Guangdong Electrical Engineering Electromagnetism electromagnetic scattering radar modulation transfer function hydrodynamic modulation transfer function third-scale effect Doppler <p>The spatial/time spectrum of short sea waves and radar observed signals are locally modulated by the presence of longer waves or currents. There are two different modulations: tilt modulation and hydrodynamic modulation. Variations in the short sea waves spectrum are described by the "hydrodynamic modulation transfer function" (HMTF). The nonlinear interaction between short sea waves and longer waves makes such modulation. Variations of radar signals are described by the "radar modulation transfer function" (RMTF). In this study, new numerical methods based on numerical nonlinear hydrodynamics and computational electromagnetics are developed to examine modulation in sea surface scattering and to examine the accuracy of existing analytical models. </p><p>Electromagnetic scattering from sea surface at low-grazing-angles (LGA) is studied by comparing analytical scattering models. The two-scale model (TSM) is found to yield the most reasonable performance among these models. Ocean surface profile retrieval based on the TSM is also shown to have an acceptable accuracy.</p><p>Numerical methods are developed to calculate the HMTF, and RMTF by use of the fast nonlinear hydrodynamics, and by use of the fast computational electromagnetics techniques. These techniques allow us to study the scattering from a stochastic "Pierson-Moskowitz" like surface with Monte-Carlo simulation. </p><p>HMTF values obtained from the simulations are compared to those from a first order wave action solution, and found to be in reasonable agreement, although differences on the order of 10% are observed. A numerical evaluation of long wave effects on the short wave dispersion relation is also provided. </p><p>The numerical method provides a quantitative way to examine the "third-scale" effect in the two-scale model. The results demonstrate that the intermediate waves influence the RMTF and are modulated by longer waves. This effect explains the RHMTF polarization dependence. Numerical results of the "third-scale" effect match well with empirical and analytical results.</p><p>A new analytical Doppler formula is derived from the nonlinear hydrodynamics. The solution is validated by numerical solutions and supported by radar Doppler simulation. Ocean surface profile retrieval based on Doppler information is shown to have a very good accuracy.</p> 2008-03-18 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1204559229 http://rave.ohiolink.edu/etdc/view?acc_num=osu1204559229 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Electrical Engineering
Electromagnetism
electromagnetic scattering
radar modulation transfer function
hydrodynamic modulation transfer function
third-scale effect
Doppler
spellingShingle Electrical Engineering
Electromagnetism
electromagnetic scattering
radar modulation transfer function
hydrodynamic modulation transfer function
third-scale effect
Doppler
Pan, Guangdong
Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces
author Pan, Guangdong
author_facet Pan, Guangdong
author_sort Pan, Guangdong
title Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces
title_short Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces
title_full Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces
title_fullStr Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces
title_full_unstemmed Electromagnetic Backscattering Studies of Nonlinear Ocean Surfaces
title_sort electromagnetic backscattering studies of nonlinear ocean surfaces
publisher The Ohio State University / OhioLINK
publishDate 2008
url http://rave.ohiolink.edu/etdc/view?acc_num=osu1204559229
work_keys_str_mv AT panguangdong electromagneticbackscatteringstudiesofnonlinearoceansurfaces
_version_ 1719427210839851008

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