Journal ArticleDOI
Derivation of directional ocean‐wave spectra by integral inversion of second‐order radar echoes
TLDR
In this paper, the inversion of a two-dimensional nonlinear integral equation is used to obtain the second-order radar cross-section in terms of the ocean-wave spectrum.Abstract:
The derivation of sea-state from a single decameter radio wave-scatter observation requires the inversion of a two-dimensional nonlinear integral equation which gives the second-order radar cross section in terms of the ocean-wave spectrum. The second-order structure is sensitive to the directional properties of waves moving slower than the wind and the total nondirectional energy spectrum. We show how these properties, together with the rms waveheight and the wind direction, may be obtained by inverting the integral equation. The inversion method depends on recognition of physical properties of the wave-wave interactions which allow linearization of the equation, followed by application of standard inversion methods. This method is tested by application to simulated Doppler spectra corresponding to known ocean wave spectra. For typical examples (radar frequency 30 MHz, Doppler resolution 0.01 Hz, with 20 range and 10 time cells averaged) the directional ocean-wave spectrum was reproduced to within 10%, the true wind direction obtained to within 5 deg, and the rms waveheight predicted to within 5%.read more
Citations
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Journal ArticleDOI
Extraction of wave parameters from measured HF radar sea-echo Doppler spectra
TL;DR: In this paper, a closed-form inversion model for wave height and dominant wave period extraction from radar sea-echo Doppler spectra has been proposed and compared with the actual values input to the original equations for scatter.
Journal ArticleDOI
A relaxation method for integral inversion applied to HF radar measurement of the ocean wave directional spectrum
TL;DR: In this article, the Chahine-Twomey relaxation method for inversion of the atmospheric radiative transfer equation is extended to provide an inverse solution to Barrick's equation describing second order scatter of high frequency (HF) radio waves from the ocean surface.
Journal ArticleDOI
Operational Wave, Current, and Wind Measurements With the Pisces HF Radar
TL;DR: In this paper, the authors present results of a trial of a Pisces HF radar system aimed at assessing its use as a component of a wave-monitoring network being installed around the coasts of England and Wales.
Journal ArticleDOI
The ocean waveheight nondirectional spectrum from inversion of the HF sea-echo Doppler spectrum
TL;DR: In this paper, a simple inversion technique for obtaining the wave height non-directional spectrum is presented, independent of the wave directionality factor, the radar look direction, or the stage of development of wave height spectrum.
Journal ArticleDOI
Ship detection with high-resolution HF skywave radar
TL;DR: In this paper, the authors present an overview of ship detection by high-frequency (HF) skywave backscatter over-the-horizon radar (OTHR) that uses sufficient resolution in the radar spatial and Doppler frequency domains.
References
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Journal ArticleDOI
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Proceedings ArticleDOI
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TL;DR: In this paper, the authors present several radar techniques which allow the remote measurement of certain parameters important in the description of sea state, such as the ocean wave height spectrum with several frequencies via firstorder Bragg scatter.