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Title: Modelling and characterisation of radar sea clutter
Author: Walker, Dominic
ISNI:       0000 0001 3553 1061
Awarding Body: University of London
Current Institution: University College London (University of London)
Date of Award: 2002
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This thesis uses the analysis of radar data recorded in the controlled environment of a laboratory wave tank to develop ideas on the nature of the dominant mechanisms in microwave scattering from the sea surface. These ideas are then extended to the case of radar sea clutter recorded in coastal waters, and the individual mechanisms identified are investigated and reproduced using theoretical and numerical electromagnetic scattering calculations. In this way the stepping stone of the laboratory wave tank provides a link between the scattering calculations, necessarily performed for idealised surfaces, and radar clutter measurements made in operationally relevant and realistic environments. Experimental observations made in the wave tank lead to the formulation of a Doppler model for radar backscatter from a water surface consisting of small scale ripples and larger, breaking waves. This model succinctly captures the polarisation and Doppler characteristics of the three scattering mechanisms found to be dominant, and can provide information on the relative strengths of two distinct types of scattering associated with steep and breaking waves. This ability to deconstruct the Doppler spectra into physically motivated basis components is shown to shed new light on the mechanisms which lead to the visibility in radar imagery of sea surface features caused by the modulation of surface waves by currents. Using a powerful numerical scattering code running on a muti-processor computer, backscatter intensity and Doppler characteristics of the components which make up the model are reproduced. The results are found to compare well with both data recorded in the wave tank, and to established, perturbation model results.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Microwave scattering