Skip to main content

Advertisement

SpringerLink
Log in

Wind-speed inversion from HF radar first-order backscatter signal

  • Published:
Ocean Dynamics Aims and scope Submit manuscript

Abstract

Land-based high-frequency (HF) radars have the unique capability of continuously monitoring ocean surface environments at ranges up to 200 km off the coast. They provide reliable data on ocean surface currents and under slightly stricter conditions can also give information on ocean waves. Although extraction of wind direction is possible, estimation of wind speed poses a challenge. Existing methods estimate wind speed indirectly from the radar derived ocean wave spectrum, which is estimated from the second-order sidebands of the radar Doppler spectrum. The latter is extracted at shorter ranges compared with the first-order signal, thus limiting the method to short distances. Given this limitation, we explore the possibility of deriving wind speed from radar first-order backscatter signal. Two new methods are developed and presented that explore the relationship between wind speed and wave generation at the Bragg frequency matching that of the radar. One of the methods utilizes the absolute energy level of the radar first-order peaks while the second method uses the directional spreading of the wind generated waves at the Bragg frequency. For both methods, artificial neural network analysis is performed to derive the interdependence of the relevant parameters with wind speed. The first method is suitable for application only at single locations where in situ data are available and the network has been trained for while the second method can also be used outside of the training location on any point within the radar coverage area. Both methods require two or more radar sites and information on the radio beam direction. The methods are verified with data collected in Fedje, Norway, and the Ligurian Sea, Italy using beam forming HF WEllen RAdar (WERA) systems operated at 27.68 and 12.5 MHz, respectively. The results show that application of either method requires wind speeds above a minimum value (lower limit). This limit is radar frequency dependent and is 2.5 and 4.0 m/s for 27.68 and 12.5 MHz, respectively. In addition, an upper limit is identified which is caused by wave energy saturation at the Bragg wave frequency. Estimation of this limit took place through an evaluation of a year long database of ocean spectra generated by a numerical model (third generation WAM). It was found to be at 9.0 and 11.0 m/s for 27.68 and 12.5 MHz, respectively. Above this saturation limit, conventional second-order methods have to be applied, which at this range of wind speed no longer suffer from low signal-to-noise ratios. For use in operational systems, a hybrid of first- and second-order methods is recommended.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15

Similar content being viewed by others

References

  • Apel J (1994) An improved model of the ocean surface wave vector spectrum and its effects on radar backscatter. J Geophys Res 99(C8):16269–16291. doi:10.1029/94JC00846

    Article  Google Scholar 

  • Banner M (1990) Equilibrium spectra of wind waves. J Phys Oceanogr 20:966–985

    Article  Google Scholar 

  • Banner M, Jones I, Trinder J (1989) Wavenumber spectra of short gravity waves. J Fluid Mech 198:321–344. doi:10.1017/S0022112089000157

    Article  Google Scholar 

  • Barrick D (1971a) Theory of HF and VHF propagation across the Rough Sea, part I: the effective surface impedance for a slightly rough highly conducting medium at grazing incidence. Radio Sci 6(5):517–526. doi:10.1029/RS006i005p00517

    Article  Google Scholar 

  • Barrick D (1971b) Theory of HF and VHF propagation across the Rough Sea, part II: application to HF and VHF propagation above the sea. Radio Sci 6(5):527–533. doi:10.1029/RS006i005p00527

    Article  Google Scholar 

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

    Article  Google Scholar 

  • Barrick D (1972b) Remote sensing of sea state by radar. In: Derr VE (ed) Remote sensing of the troposphere. US Government Printing Office, Washington

    Google Scholar 

  • Barrick D (1977a) Extraction of wave parameters from measured HF radar sea-echo Doppler spectra. Radio Sci 12(3):415–424

    Article  Google Scholar 

  • Barrick D (1977b) Ocean surface current mapped by radar. Science 198:138–144

    Article  Google Scholar 

  • Barrick D (1977c) The ocean waveheight nondirectional spectrum from inversion of the HF sea-echo Doppler spectrum. Remote Sens Environ 6:201–227. doi:10.1016/0034-4257(77)90004-9

    Article  Google Scholar 

  • Barrick D, Headrick J, Bogle R, Crombie D (1974) Sea backscatter at HF: interpretation and utilization of the echo. In: Proc. IEEE, vol 62(6)

  • Crombie D (1955) Doppler spectrum of sea echo at 13.56 Mc./s. Nature 4459:681–682. doi:10.1038/175681a0

    Article  Google Scholar 

  • Demuth H, Beale M, Hagan M (2009) Neural network toolbox 6—user’s guide. Mathworks Inc, Natick

  • Dexter P, Theodorides S (1982) Surface wind speed extraction from HF sky-wave radar Doppler spectra. Radio Sci 17(3):643–652

    Article  Google Scholar 

  • Donelan M, Pierson W Jr (1987) Radar scattering and equilibrium ranges in wind-generated waves with application to scatterometry. J Geophys Res 92(C5):4971–5029. doi:10.1029/JC092iC05p04971

    Article  Google Scholar 

  • Donelan M, Hamilton J, Hui W (1985) Directional spectra of wind-generated waves. Philos Trans R Soc Lond Ser A Math Phys Sci 315:509–562

    Article  Google Scholar 

  • Elfouhaily T, Chapron B, Katsaros K, Vandemark D (1997) A unified directional spectrum for long and short wind-driven waves. J Geophys Res 102(C7):15,781–15,796. doi:10.1029/97JC00467

    Article  Google Scholar 

  • Fisher C, Young G, Winstead N, Haqq-Misra J (2008) Comparison of synthetic aperture radar-derived wind speeds with buoy wind speeds along the mountainous Alaskan Coast. J Appl Meterol Climatol 47:1365–1376. doi:10.1175/2007JAMC1716.1

    Article  Google Scholar 

  • Forget P, Broche P, de Maistre J (1982) Attenuation with distance and wind speed of HF surface waves over the ocean. Radio Sci 17(3):599–610. doi:10.1029/RS017i003p00599

    Article  Google Scholar 

  • Gagnaire E, Benoit M, Forget P (2010) Ocean wave spectrum properties as derived from quasi-exact computations of nonlinear wave-wave interactions. J Geophys Res 115(C12058):1–24. doi:10.1029/2009JC005665

    Google Scholar 

  • Gill E, Walsh J (2001) High-frequency bistatic cross sections of ocean surface. Radio Sci 36(6):1459–1475

    Article  Google Scholar 

  • Green D, Gill E, Huang W (2009) An inversion method for extraction of wind speed from high-frequency ground-wave radar oceanic backscatter. IEEE Trans Geosci Remote Sens 47(10):3338–3346

    Article  Google Scholar 

  • Günther H, Gurgel KW, Evensen G, Wyatt L, Guddal J, Borge JN, Reichert K, Rosenthal W (1998) EuroROSE—European radar ocean sensing. In: Proceedings of the COST conference provision and engineering/operational application of wave spectra. Paris, France, 21–25 September 1998

  • Gurgel KW, Antonischki G, Essen HH, Schlick T (1999a) Wellen radar (WERA): a new ground-wave HF radar for ocean remote sensing. Coast Eng 37:219–234

    Article  Google Scholar 

  • Gurgel KW, Essen HH, Kingsley S (1999b) HF radars: physical limitation and recent developments. Coast Eng 37:201–218

    Article  Google Scholar 

  • Gurgel KW, Essen HH, Schlick T (2006) An empirical method to derive ocean waves from second-order Bragg scattering: prospects and limitations. IEEE J Oceanic Eng 31(4):804–811

    Article  Google Scholar 

  • Gurgel KW, Schlick T, Voulgaris G, Seemann J, Ziemer F (2011) HF radar observations in the German bight: measurements and quality control. In: Proceedings of the tenth IEEE/OES current, waves and turbulence measurement workshop (CWTM), Monterey, California, USA, 20–23 March 2011

  • Harlan J, Georges T (1994) An empirical relation between ocean-surface wind direction and the Bragg line ratio of HF radar sea echo spectra. J Geophys Res 99(C4):7971–7978

    Article  Google Scholar 

  • Hasselman K, Barnett T, Bouws E, Carlson H, Cartwright D, Enke K, Ewing J, Gienapp H, Hasselmann D, Kruseman P, Meerburg A, Müller P, Olbers D, Richter K, Sell W, Walden H (1973) Measurements of wind-wave growth and swell decay during the joint north sea wave project (JONSWAP). Ergänzungsheft zur Deutschen Hydrographischen Zeitschrift 8(12):95

    Google Scholar 

  • Hasselmann K (1971) Determination of ocean wave spectra from Doppler radio return from the sea surface. Nat Phys Sci 229:16–17. doi:10.1038/physci229016a0

    Google Scholar 

  • Hasselmann D, Dunckel M, Ewing J (1980) Directional wave spectra observed during JONSWAP 1973. J Phys Oceanogr 10:1264–1280

    Article  Google Scholar 

  • Hasselmann S, Hasselmann K, Bauer E, Janssen P, Komen G, Bertotti L, Lionello P, Guillaume A, Cardone V, Greenwood J, Reistad M, Zambresky L, Ewing J (1988) The WAM model—a third generation ocean waves prediction model. J Phys Oceanogr 18:1775–1810

    Article  Google Scholar 

  • Haus B, Work P, Voulgaris G, Shay N, Ramos R, Martinez J (2010) Wind speed dependence of single site wave height retrievals from phased-array HF radars. J Geophys Res 27:1381–1394. doi:10.1175/2010JTECHO730.1

    Google Scholar 

  • Heron M, Rose R (1986) On the application of HF ocean radar to the observation of temporal and spatial changes in wind direction. IEEE J Oceanic Eng OE-11(2):210–218

    Article  Google Scholar 

  • Heron M, Prytz A (2002) Wave height and wind direction from the HF coastal ocean surface radar. Can J Remote Sens 28(3):385–393

    Article  Google Scholar 

  • Kaastra I, Boyd M (1996) Designing a neural network for forecasting financial and economic time series. Neurocomputing 10:215–236

    Article  Google Scholar 

  • Kudryavtsev V, Akimov D, Johannessen J, Chapron B (2005) On radar imaging of current features: 1. Model and comparison with observations. J Geophys Res 110(C07016):1–27. doi:10.1029/2004JC002505

    Google Scholar 

  • Lavrenov I (2003) Wind-waves in oceans: dynamics and numerial simulations. Springer, Berlin

    Google Scholar 

  • Marquardt D (1963) An algorithm for least-squares estimation of nonlinear parameters. J Soc Ind Appl Math 11(2):431–441

    Article  Google Scholar 

  • Monaldo F, Thompson D, Beal R, Pichel W, Clemente-Colon P (2001) Comparison of SAR-derived wind speed with model predictions and ocean buoy measurements. IEEE Trans Geosci Remote Sens 39(12):2587–2600. doi:10.1109/36.974994

    Article  Google Scholar 

  • Parks A, Shay L, Johns W, Martinez-Pedraja J, Gurgel KW (2009) HF radar observations of small-scale surface current variability in the straits of Florida. J Geophys Res 114:C08,002, 1–17. doi:10.1029/2008JC005025

    Article  Google Scholar 

  • Pierson W, Moskowitz L (1964) A proposed spectral form of fully developed wind seas based on similarity theory of S.A. Kitaigorodskii. J Geophys Res C,69:5191–5204

    Article  Google Scholar 

  • Rojas R (1996) Neural networks: a systematic introduction. Springer, Berlin

    Google Scholar 

  • Rumelhart D, Hinton G, Williams R (1986) Learning representations by back-propagating errors. Nature 323:533–536. doi:10.1038/323533a0/

    Article  Google Scholar 

  • Savidge D, Amft J, Gargett A, Archer M, Conley D, Voulgaris G, Wyatt L, Gurgel KW (2011) Assessment of WERA long-range HF-radar performance from the user’s perspective. In: Proceedings of the tenth IEEE/OES current, waves and turbulence measurement workshop (CWTM). Monterey, California, USA, 20–23 March 2011

  • Schroeder L, Schaffner P, Mitchell J, Jones W (1985) AAFE RADSCAT 13.9-GHz measurements and analysis: wind-speed signature of the ocean. IEEE J Oceanic Eng 10(4):346–357. doi:10.1109/JOE.1985.1145123

    Article  Google Scholar 

  • Shearman E (1983) Propagation and scattering in mf/hf groundwave radar. In: IEE Proceedings F, vol 130(7), pp 579–590. doi:10.1049/ip-f-1:19830092

    Google Scholar 

  • Soares CG (2008) Hindcast of dynamic processes of the ocean and coastal areas of Europe. Coast Eng 55(11):825–826. doi:10.1016/j.coastaleng.2008.02.007

    Article  Google Scholar 

  • Stewart, RH and Barnum, JR (1975) Radio measurements of oceanic winds at long ranges: an evaluation. Radio Sci 10(10):853–857. doi:10.1029/RS010i010p00853

    Article  Google Scholar 

  • Tattelman P (1975) Surface gustiness and wind speed range as a function of time interval and mean wind speed. J Appl Meteorol 14(7):1271–1276

    Article  Google Scholar 

  • Tyler G, Teague C, Stewart R, Peterson A, Munk W, Joy J (1974) Wave directional spectra from synthetic aperture observations of radio scatter. Deep Sea Res 21(12):989–1016. doi:10.1016/0011-7471(74)90063-1

    Google Scholar 

  • Vesecky J, Drake J, Laws K, Ludwig F, Teague C, Paduan J, Meadows L (2005) Using multifrequency HF radar to estimate ocean wind fields. In: Proceedings of the 25th IEEE international geoscience and remote sensing symposium (IGARSS 2005), Seoul, Korea, 25–29 July 2005

  • Wyatt L (1986) The measurement of the ocean wave directional spectrum from HF radar Doppler spectra. Radio Sci 21(3):473–485

    Article  Google Scholar 

  • Wyatt L, Green J, Middleditch A, Moorhead M, Howarth J, Holt M, Keogh S (2006) Operational wave, current, and wind measurements with the pisces HF radar. IEEE J Oceanic Eng 31(4):819–834. doi:10.1109/JOE.2006.888378

    Article  Google Scholar 

Download references

Acknowledgments

The authors would like to thank Heinz Günther from the Helmholz–Zentrum Geesthacht (former GKSS Research Center) for providing the HIPOCAS WAM model data, the EuroROSE consortium for providing the Fedje experiment data set, and NURC for providing the Ligurian Sea experiment data set to Klaus-Werner Gurgel. The first author was supported by the China Scholarship Council while Deutscher Akademischer Austausch Dienst (DAAD) provided a research grant to George Voulgaris for his visit to the University of Hamburg. Finally, the authors would like to acknowledge the contribution of the two anonymous reviewers whose comments helped us improve this manuscript.

Author information

Authors and Affiliations

  1. Institute of Oceanography, University of Hamburg, Bundesstrasse 53, 20146, Hamburg, Germany

    Wei Shen, Klaus-Werner Gurgel, Thomas Schlick & Detlef Stammer

  2. Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC, 29208, USA

    George Voulgaris

Authors
  1. Wei Shen
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Klaus-Werner Gurgel
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. George Voulgaris
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Thomas Schlick
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Detlef Stammer
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Klaus-Werner Gurgel.

Additional information

Responsible Editor: Michel Rixen

Topical Collection on Maritime Rapid Environmental Assessment.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Shen, W., Gurgel, KW., Voulgaris, G. et al. Wind-speed inversion from HF radar first-order backscatter signal. Ocean Dynamics 62, 105–121 (2012). https://doi.org/10.1007/s10236-011-0465-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10236-011-0465-9

Keywords

Search

Navigation