Measuring Ocean Surface Waves Using HF Ground Wave Radar: Validation Against a Wave Model

Howell, R.; Khandekar, M. L.

doi:10.1080/07038992.1993.10855157

Cited by 5 publications

(2 citation statements)

References 2 publications

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“…Hence OSMAR071 is more suitable for detecting high sea state dynamics. Some authors had already studied the relationship between HF radar working frequency and detectable wave frequency band [17,18] . Other aspects are also believed to contribute to explain the biases between the radar and buoy results.…”

Section: Verification and Analysis Of The Modified Barrick Modelmentioning

confidence: 99%

Experimental determination of significant waveheight by OSMAR071: Comparison with results from buoy

Shao

et al. 2009

Wuhan Univ. J. Nat. Sci.

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OSMAR071 is the latest product of the OSMAR (ocean state monitor and analysis radar) series of high frequency surface wave radar (HFSWR), which was developed by the Radiowave Propagation Laboratory of Wuhan University. It adopts a modified Barrick waveheight inversion model. The modifications are introduced to improve the model's performances under the effect of noises and interferences and in the case of broad beam radar detection. The two unknown coefficients in the modified model are figured out by fitting the HFSWR significant waveheight results to those output from a wave buoy located in the radiating coverage of the radar site. The model is applied to inverse the waveheights from radar data for the duration from Dec. 1st, 2008 to Feb. 25th, 2009, and then the radar waveheights are compared with the buoy measurements. Results show that the rms difference between radar-derived significant waveheights and those from the buoy is 0.38 m and the correlation coefficient between the two series is 0.66. This study describes OSMAR071 observation of significant waveheight with relatively satisfactory accuracy during about three months.High frequency surface wave radar (HFSWR) operated in the HF band (3-30 MHz), as the name suggests, employs the ground wave mode of radio wave propagation, in which the radar signal is guided by a good conducting surface such as the ocean surface to follow a path that essentially matches the earth's curvature. It is capable of all-weather remote sensing of large-area ocean surface dynamics with relatively high precision [1] . After more than 40 years' development, its capability of current detection has been considered to satisfy the requirements for routine marine observations while its wind and wave outputs have not reached the matched status [2] . Currents information can be extracted from the broadening of the Bragg peaks (which are also called as the first-order peaks) in the sea echoes' Doppler spectra. The second-order continuum which contain the information of waves and winds is relatively weak (20-40 dB lower than the Bragg peaks) and susceptible to the effect of noise and interference, so the extraction of waves and winds information is difficult [3] and the corresponding inversion theory and technology are still currently under development. Much progress has been made to understand the relationship between the Doppler spectrum of the radar backscatter signals and the ocean wave spectrum [4] . In 1977 Barrick proposed an inversion model of significant waveheight [5] , which can work robustiously in practice [6,7] . It is different from several other algorithms, which relate the inversion of wave spectra to the second-order sea echoes directly. Therefore, the significant

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Section: Verification and Analysis Of The Modified Barrick Modelmentioning

confidence: 99%

Experimental determination of significant waveheight by OSMAR071: Comparison with results from buoy

Shao

et al. 2009

Wuhan Univ. J. Nat. Sci.

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show abstract

“…The system measures currents by estimating the difference in Doppler shift between the observed backscatter and that expected for the Bragg resonant waves causing the backscatter: about 22 m in wavelength in this case. It estimates the wave power spectra by inverting the second-order Doppler peaks in a limited range of Doppler frequencies (Howell and Khandekar, 1993), and by supplementing the high-frequency tails of the inverted spectra with a Pierson-Moskowitz frequency spectrum. Although the potential exists for the calculation of left-right (with respect to the radar beam) directional wave height spectra, only heave spectra have been calculated.…”

Section: Nrsl Hf Radarmentioning

confidence: 99%