An efficient and accurate solution for the extraction of non-directional ocean wave spectra from second-order high-frequency radar Doppler spectra

2017 ◽  
Author(s):  
Reza Shahidi ◽  
Eric W. Gill
Keyword(s):  
High Frequency ◽  
Accurate Solution ◽  
Second Order ◽  
Ocean Wave ◽  
Wave Spectra ◽  
High Frequency Radar

scholarly journals Wind Speed and Direction Estimation from Wave Spectra using Deep Learning

2021 ◽  
Author(s):  
Haoyu Jiang
Keyword(s):  
Wind Speed ◽  
High Frequency ◽  
Deep Neural Networks ◽  
Fourier Coefficients ◽  
Ocean Wave ◽  
Wave Spectra ◽  
Strongly Coupled ◽  
Wave Measurements ◽  
Short Period ◽  
Wind Measurements

Abstract. High-frequency parts of ocean wave spectra are strongly coupled to the local wind. Measurements of ocean wave spectra can be used to estimate sea surface winds. In this study, two deep neural networks (DNNs) were used to estimate the wind speed and direction from the first five Fourier coefficients from buoys. The DNNs were trained by wind and wave measurements from more than 100 meteorological buoys during 2014–2018. It is found that the wave measurements can best represent the wind information ~1 h ago, because the wave spectra contain wind information a short period before. The overall root-mean-square error (RMSE) of estimated wind speed is ~1.1 m/s, and the RMSE of wind direction is ~14° when wind speed is 7~25 m/s. This model can not only be used for the wind estimation for compact wave buoys but also for the quality control of wind and wave measurements from meteorological buoys.

scholarly journals Bistatic High Frequency Radar Ocean Surface Cross Section for an FMCW Source with an Antenna on a Floating Platform

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Yue Ma ◽  
Weimin Huang ◽  
Eric W. Gill
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
High Frequency ◽  
Continuous Wave ◽  
Ocean Surface ◽  
Radar Cross Section ◽  
Second Order ◽  
Floating Platform ◽  
High Frequency Radar ◽  
Radar Cross Sections

The first- and second-order bistatic high frequency radar cross sections of the ocean surface with an antenna on a floating platform are derived for a frequency-modulated continuous wave (FMCW) source. Based on previous work, the derivation begins with the general bistatic electric field in the frequency domain for the case of a floating antenna. Demodulation and range transformation are used to obtain the range information, distinguishing the process from that used for a pulsed radar. After Fourier-transforming the autocorrelation and comparing the result with the radar range equation, the radar cross sections are derived. The new first- and second-order antenna-motion-incorporated bistatic radar cross section models for an FMCW source are simulated and compared with those for a pulsed source. Results show that, for the same radar operating parameters, the first-order radar cross section for the FMCW waveform is a little lower than that for a pulsed source. The second-order radar cross section for the FMCW waveform reduces to that for the pulsed waveform when the scattering patch limit approaches infinity. The effect of platform motion on the radar cross sections for an FMCW waveform is investigated for a variety of sea states and operating frequencies and, in general, is found to be similar to that for a pulsed waveform.

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