An Empirical Method to Derive Ocean Waves From Second-Order Bragg Scattering: Prospects and Limitations

Gurgel, Klaus-Werner; Essen, H.‐H.; Schlick, T.

doi:10.1109/joe.2006.886225

Cited by 68 publications

(62 citation statements)

References 8 publications

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“…Barrick and Weber (1977) provided a solution to this scattering problem which can be written in the form of a non-linear integral equation (Lipa and Barrick, 1986;Holden and Wyatt, 1992). Wave measurements are made either by inverting this equation (Barrick, 1977;Lipa, 1977;Wyatt, 1990;Hisaki, 1996;Hashimoto and Tokuda, 1999;Green and Wyatt, 2006) or by empirical methods obtained by relating the amplitude, or integrated amplitude, of the second order spectrum (or moments thereof) to wave buoy measurements (Maresca and Georges, 1980;Wyatt, 2002;Gurgel et al, 2006;Wang et al, 2016). Note that this latter approach is sensitive to water depth and users have found it necessary to recalibrate in different situations.…”

Section: Basic Principles Of Hfr Operation and Data Specificationsmentioning

confidence: 99%

HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network

et al. 2017

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High Frequency Radar (HFR) is a land-based remote sensing instrument offering a unique insight to coastal ocean variability, by providing synoptic, high frequency and high resolution data at the ocean atmosphere interface. HFRs have become invaluable tools in the field of operational oceanography for measuring surface currents, waves and winds, with direct applications in different sectors and an unprecedented potential for the integrated management of the coastal zone. In Europe, the number of HFR networks has been showing a significant growth over the past 10 years, with over 50 HFRs currently deployed and a number in the planning stage. There is also a growing literature concerning the use of this technology in research and operational oceanography. A big effort is made in Europe toward a coordinated development of coastal HFR technology and its products within the framework of different European and international initiatives. One recent initiative has been to make an up-to-date inventory of the existing HFR operational systems in Europe, describing the characteristics of the systems, their operational products and applications. This paper offers a comprehensive review on the present status of European HFR network, and discusses the next steps toward the integration of HFR platforms as operational components of the European Ocean Observing System, designed to align and integrate Europe's ocean observing capacity for a truly integrated end-to-end observing system for the European coasts.

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Section: Basic Principles Of Hfr Operation and Data Specificationsmentioning

confidence: 99%

HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network

et al. 2017

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“…The model chosen here to approximate the azimuthal variation in wave energy around the wind direction, as represented by Shen et al (2012) and Gurgel et al (2006), is…”

Section: Description Of Best-fit Modelmentioning

confidence: 99%

Remote Sensing of the Surface Wind Field over the Coastal Ocean via Direct Calibration of HF Radar Backscatter Power

Kirincich

2016

Journal of Atmospheric and Oceanic Technology

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The calibration and validation of a novel approach to remotely sense surface winds using land-based highfrequency (HF) radar systems are described. Potentially available on time scales of tens of minutes and spatial scales of 2-3 km for wide swaths of the coastal ocean, HF radar-based surface wind observations would greatly aid coastal ocean planners, researchers, and operational stakeholders by providing detailed real-time estimates and climatologies of coastal winds, as well as enabling higher-quality short-term forecasts of the spatially dependent wind field. Such observations are particularly critical for the developing offshore wind energy community. An autonomous surface vehicle was deployed within the Massachusetts Wind Energy Area, located south of Martha's Vineyard, Massachusetts, for one month, collecting wind observations that were used to test models of wind-wave spreading and HF radar energy loss, thereby empirically relating radarmeasured power to surface winds. HF radar-based extractions of the remote wind speed had accuracies of 1.4 m s 21 for winds less than 7 m s 21, within the optimal range of the radar frequency used. Accuracies degraded at higher winds due to low signal-to-noise ratios in the returned power and poor resolution of the model. Pairing radar systems with a range of transmit frequencies with adjustments of the extraction model for additional power and environmental factors would resolve many of the errors observed.

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“…Furthermore, a fetchx close to 10 5 indicates that the JONSWAP and P-M spectra are nearly identical and γ ≈ 1.0. According to the relationship between significant wave height and wind speed examined by the buoys data collected at Taiwan Strait, we find that the resulted fetchx is around 10 4 . Figure 1 shows the JONSWAP wave spectra under different wind speeds withx = 10 4 .…”

Section: Relationship Between First-order Echo Power and Wave Heightmentioning

confidence: 95%

“…Whereas, the situation is not so good for wave and wind parameters estimation due to the relative low robustness and accuracy. Wave information extraction has always been conducted using the second-order continuum of radar echo, with the classic integral inversion method by Barrick [2] or other algorithms by Lipa [3], Gurgel [4], Wyatt [5,6] and Hisaki [7] etc. The second-order scattering based methods significantly rely on the echo quality which varies with sea state [8].…”

Section: Introductionmentioning

confidence: 99%

Wave Height Estimation from First-Order Backscatter of a Dual-Frequency High Frequency Radar

et al. 2017

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Second-order scattering based wave height measurement with high-frequency (HF) radar has always been subjected to problems such as distance limitation and external interference especially under low or moderate sea state. The performance is further exacerbated for a compact system with small antennas. First-order Bragg scattering has been investigated to relate wave height to the stronger Bragg backscatter, but calibrating the echo power along distance and direction is challenging. In this paper, a new method is presented to deal with the calibration and improve the Bragg scattering based wave height estimation from dual-frequency radar data. The relative difference of propagation attenuation and directional spreading between two operating frequencies has been found to be identifiable along range and almost independent of direction, and it is employed to effectively reduce the fitting requirements of in situ wave buoys. A 20-day experiment was performed over the Taiwan Strait of China to validate this method. Comparison of wave height measured by radar and buoys at distance of 15 km and 70 km shows that the root-mean-square errors are 0.34 m and 0.56 m, respectively, with correlation coefficient of 0.82 and 0.84.

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An Empirical Method to Derive Ocean Waves From Second-Order Bragg Scattering: Prospects and Limitations

Cited by 68 publications

References 8 publications

HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network

HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network

Remote Sensing of the Surface Wind Field over the Coastal Ocean via Direct Calibration of HF Radar Backscatter Power

Wave Height Estimation from First-Order Backscatter of a Dual-Frequency High Frequency Radar

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