A Comparison of Algorithms for Extracting Significant Wave Height from HF Radar Ocean Backscatter Spectra

S. F. Heron Physics Department, James Cook University, Townsville, Australia

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M. L. Heron Physics Department, James Cook University, Townsville, Australia

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Abstract

A comparison is made between three different but related algorithms for the extraction of rms wave heights from high frequency ocean backscatter radar spectra. All three methods are based on the ratio of second- to first-order energies as developed by Barrick, and each was scaled so that the mean values of the radar analysis results and the corresponding wave buoy data were zero. The rms difference between the radar wave heights and those from the buoy was taken as a measure of fit, and the recommended algorithm had an rms difference value of 7 cm. Barrick’s algorithm (after scaling), which uses a weighted second-order energy integral, performed marginally better than the others. The condition requiring wind directions other than close to orthogonal to the radar beam is retained in the recommended algorithm but is not evaluated because of sparsity of data. The algorithm for extraction of rms wave heights is validated against the buoy data over rms wave height ranges from about 0.2 to 0.7 m.

Corresponding author address: Prof. Mal L. Heron, Physics Department, James Cook University, Townsville 4811, Queensland, Australia.

Email: mal.heron@jcu.edu.au

Abstract

A comparison is made between three different but related algorithms for the extraction of rms wave heights from high frequency ocean backscatter radar spectra. All three methods are based on the ratio of second- to first-order energies as developed by Barrick, and each was scaled so that the mean values of the radar analysis results and the corresponding wave buoy data were zero. The rms difference between the radar wave heights and those from the buoy was taken as a measure of fit, and the recommended algorithm had an rms difference value of 7 cm. Barrick’s algorithm (after scaling), which uses a weighted second-order energy integral, performed marginally better than the others. The condition requiring wind directions other than close to orthogonal to the radar beam is retained in the recommended algorithm but is not evaluated because of sparsity of data. The algorithm for extraction of rms wave heights is validated against the buoy data over rms wave height ranges from about 0.2 to 0.7 m.

Corresponding author address: Prof. Mal L. Heron, Physics Department, James Cook University, Townsville 4811, Queensland, Australia.

Email: mal.heron@jcu.edu.au

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  • Barrick, D. E., 1972a: First-order theory and analysis of MF/HF/VHF scatter from the sea. IEEE Trans. Antennas Propag.,AP-20, 2–10.

    • Crossref
    • Export Citation
  • ——, 1972b: Remote sensing of the sea state by radar. Remote Sensing of the Troposphere, V. E. Derr, Ed., NOAA/Environmental Research Laboratories, 12-1–12-46.

  • ——, 1977: Extraction of wave parameters from measured HF radar sea-echo Doppler spectra. Radio Sci.,12, 415–424.

    • Crossref
    • Export Citation
  • Haus, B. K., H. C. Graber, L. K. Shay, and J. Martinez, 1995: Ocean surface current observations with HF Doppler radar during the DUCK94 experiment. RSMAS Tech. Rep. 95-010, University of Miami, Miami, FL, 104 pp.

  • Heron, M. L., P. E. Dexter, and B. T. McGann, 1985: Parameters of the air–sea interface by high-frequency ground–wave Doppler radar. Aust. J. Mar. Freshwater Res.,36, 655–670.

    • Crossref
    • Export Citation
  • Howell, R., and J. Walsh, 1993: Measurement of ocean wave spectra using narrow-beam HF radar. IEEE J. Oceanic Eng.,18, 295–305.

    • Crossref
    • Export Citation
  • Maresca, J. W., Jr., and T. M. Georges, 1980: Measuring rms wave height and the scalar ocean wave spectrum with HF skywave radar. J. Geophys. Res.,85, 2759–2771.

    • Crossref
    • Export Citation
  • Prandle, D., and D. K. Ryder, 1989: Comparison of observed (HF radar) and modeled nearshore velocities. Contin. Shelf Res.,9, 941–963.

    • Crossref
    • Export Citation
  • Shay, L. K., H. C. Graber, D. B. Ross, and R. D. Chapman, 1995: Mesoscale ocean surface current structure detected by high-frequency radar. J. Atmos. Oceanic Technol.,12, 881–900.

    • Crossref
    • Export Citation
  • Wyatt, L., 1986: The measurement of the ocean wave directional spectrum from HF radar Doppler spectra. Radio Sci.,21, 473–485.

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    • Export Citation
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