An algorithm for the extraction of ocean wave parameters from wide beam HF radar (CODAR) backscatter

Gill, Eric William (1990) An algorithm for the extraction of ocean wave parameters from wide beam HF radar (CODAR) backscatter. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (3MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

The remote monitoring of the coastal ocean has been a topic receiving much attention from both the scientific and industrial communities in recent years. Among the many devices which have come to the forefront in providing comprehensive information on ocean surface paramenters is the HF radar operating in the ground wave mode. In particular, a four-element square array known as a CODAR (Coastal Oceans Dynamics Applications Radar) has successfully produced near-shore current maps. The problem addressed in this thesis is that of molding existing theory so as to create an algorithm which would extend the capabilities of this CODAR to include the yielding of directional waveheight spectra from backscattered radiation. -- General expressions for the first- and second-order broad beam radar cross sections of the ocean surface presented by Barrick and Lipa (1979b) are applied to the four-element CODAR. Fourier coefficients of both the first- and second-order portions of the radar spectrum are developed with all but one of the various required integrations being carried out in closed form. The Fourier basis function approach allows the broad beam cross sections to be written as a system of integral equations. The second-order radar return involves a double integral whose integrand contains nonlinear combinations of the unknowns, namely the Fourier coefficients of the ocean wave directional spectrum. The first-order portion of the radar spectrum is used to linearize this integral, thus allowing the system of equations to be formulated in terms of matrices. The matrix system is solved using a singular value decomposition approach. -- The analysis is carried out in its entirety for simulated data only. However, Appendix D outlines the procedure for calculating the four-element square array cross sections from measured data. These may be used in the algorithms developed here to extract directional waveheight information from the backscatter of high frequency radiation from the ocean surface.

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