Wave-Height Mapping From Second-Order Harmonic Peaks of Wide-Beam HF Radar Backscatter Spectra

Abstract. The EISCAT high power heating facility at Tromsø, northern Norway, has been utilised to generate artificial radar backscatter in the fields of view of the CUTLASS HF radars. It has been demonstrated that this technique offers a means of making very accurate and high resolution observations of naturally occurring ULF waves. During such experiments, the usually narrow radar spectral widths associated with artificial irregularities increase at times when small scale-sized (high m-number) ULF waves are observed. Possible mechanisms by which these particle-driven high-m waves may modify the observed spectral widths have been investigated. The results are found to be consistent with Pc1 (ion-cyclotron) wave activity, causing aliasing of the radar spectra, in agreement with previous modelling work. The observations also support recent suggestions that Pc1 waves may be modulated by the action of longer period ULF standing waves, which are simultaneously detected on the magnetospheric field lines. Drifting ring current protons with energies of ∼ 10keV are indicated as a common plasma source population for both wave types. Key words. Magnetospheric physics (MHD waves and instabilities) – Space plasma physics (wave-particle interactions) – Ionosphere (active experiments)

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The Scattering Coefficient for Shore-to-Air Bistatic High Frequency (HF) Radar Configurations as Applied to Ocean Observations

Remote Sensing ◽

10.3390/rs11242978 ◽

2019 ◽

Vol 11 (24) ◽

pp. 2978 ◽

Cited By ~ 2

Author(s):

Zezong Chen ◽

Jian Li ◽

Chen Zhao ◽

Fan Ding ◽

Xi Chen

Keyword(s):

Electromagnetic Scattering ◽

High Frequency ◽

Doppler Frequency ◽

Second Order ◽

Hf Radar ◽

Scattering Coefficient ◽

Sea State ◽

Scattering Coefficients ◽

Wind Speeds ◽

Ocean Observations

To extend the scope of high frequency (HF) radio oceanography, a new HF radar model, named shore-to-air bistatic HF radar, has been proposed for ocean observations. To explore this model, the first-order scattering coefficient and the second-order electromagnetic scattering coefficient for shore-to-air bistatic HF radar are derived using the perturbation method. In conjunction with the contribution of the hydrodynamic component, the second-order scattering coefficient is derived. Based on the derived scattering coefficients, we analyzed the simulated echo Doppler spectra for various scattering angles and azimuthal angles, operation frequencies, wind speeds, and directions of wind, which may provide the guideline on the extraction of sea state information for shore-to-air bistatic HF radar. The singularities in the simulated echo Doppler spectra are discussed using the normalized constant Doppler frequency contours. In addition, the scattering coefficients of shore-to-air bistatic HF radar are compared with that of monostatic HF radar and land-based bistatic HF radar. The results verify the correctness of the proposed scattering coefficients. The model of shore-to-air bistatic HF radar is effective for ocean observations.

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A comparison of satellite scintillation measurements with HF radar backscatter characteristics

Annales Geophysicae ◽

10.5194/angeo-23-3451-2005 ◽

2005 ◽

Vol 23 (11) ◽

pp. 3451-3455 ◽

Cited By ~ 8

Author(s):

S. E. Milan ◽

S. Basu ◽

T. K. Yeoman ◽

R. E. Sheehan

Keyword(s):

Broad Spectrum ◽

High Latitude ◽

Auroral Zone ◽

Intersection Point ◽

Density Fluctuations ◽

Hf Radar ◽

Ionospheric Scintillation ◽

Radar Backscatter ◽

Density Perturbations ◽

Coherent Radar

Abstract. We examine the correspondence between high latitude ionospheric scintillation measurements made at 250MHz with the occurrence of 10MHz HF coherent radar backscatter, on 13 and 14 December 2002. We demonstrate that when the ionospheric intersection point of the scintillation measurements is co-located with significant HF radar backscatter, the observed scintillation, quantified by the S4 index, is elevated. Conversely, when the radar indicates that backscatter is observed away from the intersection point due to movements of the auroral zone, the observed scintillation is low. This suggests that scintillation is highly location-dependent, being enhanced in the auroral zone and being lower at sub-auroral latitudes. The coexistence of scintillation and HF radar backscatter, produced by ionospheric density perturbations with scale sizes of 100s of metres and ~15 m, respectively, suggests that a broad spectrum of density fluctuations is found in the auroral zone.

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Statistical Analysis of a Set of Basin Waves

Volume 6: Ocean Engineering ◽

10.1115/omae2011-49974 ◽

2011 ◽

Author(s):

Jule Scharnke ◽

Janou Hennig

Keyword(s):

Statistical Analysis ◽

Wave Height ◽

Water Depth ◽

Water Waves ◽

Rayleigh Distribution ◽

Second Order ◽

Distribution Functions ◽

Wave Crest ◽

Intermediate Water ◽

Wave Measurements

In a recent paper the effect of variations in calibrated wave parameters on wave crest and height distributions was analyzed (OMAE2010-20304, [1]). Theoretical distribution functions were compared to wave measurements with a variation in water depth, wave seed (group spectrum) and location of measurement for the same initial power spectrum. The wave crest distribution of the shallow water waves exceeded both second-order and Rayleigh distribution. Whereas, in intermediate water depth the measured crests followed the second order distribution. The distributions of the measured waves showed that different wave seeds result in the same wave height and crest distributions. Measured wave heights were lower closer to the wave maker. In this paper the results of the continued statistical analysis of basin waves are presented with focus on wave steepness and their influence on wave height and wave crest distributions. Furthermore, the sampling variability of the presented cases is assessed.

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Wave Height Field Extraction From First-Order Doppler Spectra of a Dual-Frequency Wide-Beam High-Frequency Surface Wave Radar

IEEE Transactions on Geoscience and Remote Sensing ◽

10.1109/tgrs.2019.2942481 ◽

2020 ◽

Vol 58 (2) ◽

pp. 1017-1029 ◽

Cited By ~ 1

Author(s):

Yingwei Tian ◽

Zhen Tian ◽

Jiurui Zhao ◽

Biyang Wen ◽

Weimin Huang

Keyword(s):

Surface Wave ◽

Wave Height ◽

High Frequency ◽

Height Field ◽

Dual Frequency ◽

Wide Beam ◽

First Order ◽

Wave Radar

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The second-order monostatic HF radar cross section incorporating antenna barge motion

2009 Canadian Conference on Electrical and Computer Engineering ◽

10.1109/ccece.2009.5090083 ◽

2009 ◽

Cited By ~ 1

Author(s):

John Walsh ◽

Weimin Huang ◽

Eric Gill

Keyword(s):

Cross Section ◽

Radar Cross Section ◽

Second Order ◽

Hf Radar

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Nonlinear Crest, Trough, and Wave Height Distributions in Sea States With Double-Peaked Spectra

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.3160657 ◽

2009 ◽

Vol 131 (4) ◽

Cited By ~ 12

Author(s):

Felice Arena ◽

C. Guedes Soares

Keyword(s):

Monte Carlo ◽

Atlantic Ocean ◽

Monte Carlo Simulations ◽

Wave Height ◽

Deep Water ◽

Second Order ◽

Statistical Distribution ◽

Random Waves ◽

Sea Waves ◽

Two Parameters

The peak to trough distributions of nonlinear high sea waves in bimodal sea states in deep water are investigated. The statistical distribution of wave height is first analyzed by considering the Boccotti’s expression, where the parameters of the distribution are calculated for some bimodal spectra of sea states recorded in the Atlantic Ocean. The nonlinear crest and trough distributions are then obtained, particularizing for two peaked spectra the second-order Fedele and Arena expression, which depends on two parameters. The results have been finally validated by means of Monte Carlo simulations of second-order random waves with bimodal spectra.

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