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Evaluation And Improvement Of Methods For Estimating Sea Surface Wave Parameters From X Band Marine Radar Data
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Book Synopsis Evaluation and Improvement of Methods for Estimating Sea Surface Wave Parameters from X-band Marine Radar Data by : Zhiding Yang
Download or read book Evaluation and Improvement of Methods for Estimating Sea Surface Wave Parameters from X-band Marine Radar Data written by Zhiding Yang and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enhanced Methods of Ocean Wave Spectra and Sea State Parameter Estimation from X-band Marine Radar Data by : Al-Abbass Y. Al-Habashneh
Download or read book Enhanced Methods of Ocean Wave Spectra and Sea State Parameter Estimation from X-band Marine Radar Data written by Al-Abbass Y. Al-Habashneh and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the ocean's importance in human lives, researchers have been studying the ocean and developing systems to estimate its state since the 19th century. During the last three decades, remote sensing of the ocean surface using X-band marine radars has emerged as a reliable tool to estimate ocean wave spectra and sea state parameters such as mean wave period and direction and significant wave height. The purpose of this thesis is to develop methods that produce accurate and reliable estimates of ocean wave spectra using X-band marine radar data. The approach taken in this thesis is to determine the sources of ocean wave spectra estimation error in existing methods and then to develop new methods that minimize those errors. In this thesis, four sources of error are addressed: the dependency of spectra estimation on the orientation of the analysis windows; the effect of the radar sampling process; the effect of the scan conversion process; and the accuracy of surface current estimation. The azimuthal location of the X-band radar data analysis window affects the estimation of ocean wave spectra. it has been reported in the literature, and supported by our results, that using the up-wave directions for analysis windows produces higher signal to noise ratios and hence more accurate ocean wave spectra estimates. In order to minimize error due to dependency on the orientation of the analysis windows, a new method referred to as the Adaptive Recursive Positioning Method (ARPM) is proposed. The ARPM is a recursive approach that dynamically determines the optimal number of analysis windows and their corresponding orientation toward the up-wave directions. Second, in this thesis, it has been demonstrated that the sampling process of the ocean surface by X-band marine radar during data collection significantly affects the estimation of ocean save spectra from X-band marine radar data. Therefore, a method referred to as the Inverse Sampling Averaging Filter (ISAF) is proposed to mitigate the effect of the radar sampling process of the ocean surface on the ocean wave spectra estimation using X-band marine radars. ISAF was designed based on a novel understanding of the radar sampling process to involve an averaging process or low pass filtering of the ocean wave spectra. Third, in this thesis, a method referred to as the Polar Fourier Transform (PFT) is proposed to eliminate the distortion presented by the scan conversion process to the estimated wave spectra. Unlike the existing methods which use the Cartesian Fourier Transform (CFT) to acquire the ocean wave spectra, the PFT method is designed to apply a Fourier-type transformation on the radar data in its native format, which is sampled in the polar coordinates, without the need for the intermediate stage of scan conversion used to map the data into Cartesian coordinates. The performance of the proposed methods, the ARPM,ISAF and PFT, are individually validated by comparing their ocean wave spectra estimates to those acquired using the existing methods with respect to ground truth wave spectra acquired using a wave rider buoy. Furthermore, the proposed methods were also combined together to seek further enhancement. The wave spectra estimation results from different combinations of the proposed methods were validated in comparison to the ground truth data. Finally, a new method to estimate surface current using X-band marine radar is proposed. This method is referred to as the Hybrid Least Squares (HLS) method. The HLS combines two existing approaches: the Iterative Least Squares (ILS) method and the Normalized Scalar Product (NSP). The HLS is designed to inherit the short computational time of ILS and the high reliability of NSP. To validate its accuracy and reliability, the proposed HLS method was applied on a number of simulated X-band marine radar image sets and the results were compared to the estimates acquired using the ILS and the NSP.
Book Synopsis Ocean Wind and Wave Parameter Estimation from Ship-borne X-band Marine Radar Data by : Xinlong Liu
Download or read book Ocean Wind and Wave Parameter Estimation from Ship-borne X-band Marine Radar Data written by Xinlong Liu and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ocean wind and wave parameters are important for the study of oceanography, on- and off-shore activities, and the safety of ship navigation. Conventionally, such parameters have been measured by in-situ sensors such as anemometers and buoys. During the last three decades, sea surface observation using X-band marine radar has drawn wide attention since marine radars can image both temporal and spatial variations of the sea surface. In this thesis, novel algorithms for wind and wave parameter retrieval from X-band marine radar data are developed and tested using radar, anemometer, and buoy data collected in a sea trial off the east coast of Canada in the North Atlantic Ocean. Rain affects radar backscatter and leads to less reliable wind parameters measurements. In this thesis, algorithms are developed to enable reliable wind parameters measurements under rain conditions. Firstly, wind directions are extracted from raincontaminated radar data using either a 1D or 2D ensemble empirical mode decomposition (EEMD) technique and are seen to compare favourably with an anemometer reference. Secondly, an algorithm based on EEMD and amplitude modulation (AM) analysis to retrieve wind direction and speed from both rain-free and rain-contaminated X-band marine radar images is developed and is shown to be an improvement over an earlier 1D spectral analysis-based method. For wave parameter measurements, an empirical modulation transfer function (MTF) is required for traditional spectral analysis-based techniques. Moreover, the widely used signal-to-noise ratio (SNR)-based method for significant wave height (HS) estimation may not always work well for a ship-borne X-band radar, and it requires external sensors for calibration. In this thesis, two methods are first presented for HS estimation from X-band marine radar data. One is an EEMD-based method, which enables satisfactory HS measurements obtained from a ship-borne radar. The other is a modified shadowingbased method, which enables HS measurements without the inclusion of external sensors. Furthermore, neither method requires the MTF. Finally, an algorithm based on the Radon transform is proposed to estimate wave direction and periods from X-band marine radar images with satisfactory results.
Book Synopsis Signal Processing Methods to Improve Ocean Surface Wave Estimation from a High Frequency Surface Wave Radar by :
Download or read book Signal Processing Methods to Improve Ocean Surface Wave Estimation from a High Frequency Surface Wave Radar written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Sea Surface Wave Reconstruction from Marine Radar Images by : Yusheng Qi (S.M.)
Download or read book Sea Surface Wave Reconstruction from Marine Radar Images written by Yusheng Qi (S.M.) and published by . This book was released on 2012 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: The X-band marine radar is one type of remote sensing technology which is being increasingly used to measure sea surface waves nowadays. In this thesis, how to reconstruct sea surface wave elevation maps from X-band marine radar images and do wave field prediction over short term in real time are discussed. The key idea of reconstruction is using dispersion relation based on the linear wave theory to separate the wave-related signal from non-wave signal in radar images. The reconstruction process involves three-dimensional Fourier analysis and some radar imaging mechanism. In this thesis, an improved shadowing simulation model combined with wave field simulation models for the study of the correction function in the reconstruction process and an improved wave scale estimation model using non-coherent radar data are proposed, which are of great importance in the reconstruction process. A radar image calibration method based on wave field simulation is put forward in order to improve the quality of reconstructed sea surface wave. Besides, a theoretical wave scale estimation model using Doppler spectra of the coherent radar is put forward, which is proposed to be a good alternative to the current wave scale estimation model. The reconstructed sea surface wave can be used for wave field simulation in order to predict the wave field, which is not only an application of this reconstruction process, but also a parameter optimizing tool for the reconstruction process.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Sea Surface Roughness Observed by High Resolution Radar by : Atsushi Fujimura
Download or read book Sea Surface Roughness Observed by High Resolution Radar written by Atsushi Fujimura and published by MDPI. This book was released on 2019-10-25 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Changes in sea surface roughness are usually associated with a change in the sea surface wind field. This interaction has been exploited to measure sea surface wind speed by scatterometry. A number of features on the sea surface associated with changes in roughness can be observed by synthetic aperture radar (SAR) because of the change in Bragg backscatter of the radar signal by damping of the resonant ocean capillary waves. With various radar frequencies, resolutions, and modes of polarization, sea surface features have been analyzed in numerous campaigns, bringing various datasets together, thus allowing for new insights into small-scale processes at a larger areal coverage. This Special Issue aims at investigating sea surface features detected by high spatial resolution radar systems, such as SAR.
Download or read book Earth Resources written by and published by . This book was released on 1983 with total page 758 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Advanced Technology Related to Radar Signal, Imaging, and Radar Cross-Section Measurement by : Hirokazu Kobayashi
Download or read book Advanced Technology Related to Radar Signal, Imaging, and Radar Cross-Section Measurement written by Hirokazu Kobayashi and published by MDPI. This book was released on 2020-06-16 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radar-related technology is mainly processed within the time and frequency domains but, at the same time, is a multi-dimensional integrated system including a spatial domain for transmitting and receiving electromagnetic waves. As a result of the enormous technological advancements of the pioneers actively discussed in this book, research and development in multi-dimensional undeveloped areas is expected to continue. This book contains state-of-the-art work that should guide your research.
Download or read book NASA SP. written by and published by . This book was released on 1962 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Extraction of Ocean Wave Information from Microwave Nautical Radar Images by : Jiaqi An
Download or read book Extraction of Ocean Wave Information from Microwave Nautical Radar Images written by Jiaqi An and published by . This book was released on 2013 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Advances in SAR Remote Sensing of Oceans by : Xiaofeng Li
Download or read book Advances in SAR Remote Sensing of Oceans written by Xiaofeng Li and published by CRC Press. This book was released on 2018-10-12 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oceans cover approximately 71% of Earth’s surface, 90% of the biosphere and contains 97% of Earth’s water. Since the first launch of SEASAT satellite in 1978, an increasing number of SAR satellites have or will become available, such as the European Space Agency’s ERS-1/-2, ENVISAT, and Sentinel-1 series; the Canadian RADARSAT-1/-2 and the upcoming RADARSAT Constellation Mission series satellites; the Italian COSMO-SkyMed satellites, the German TERRASAR-X and TANDEM-X, and the Chinese GAOFEN-3 SAR, among others. Recently, European Space Agency has launched a new generation of SAR satellites, Sentinel-1A in 2014 and Sentinel-1B in 2016. These SAR satellites provide researchers with free and open SAR images necessary to carry out their research on the global oceans. The scope of Advances in SAR Remote Sensing of Oceans is to demonstrate the types of information that can be obtained from SAR images of the oceans, and the cutting-edge methods needed for analysing SAR images. Written by leading experts in the field, and divided into four sections, the book presents the basic principles of radar backscattering from the ocean surface; introduces the recent progresses in SAR remote sensing of dynamic coastal environment and management; discusses the state-of-the-art methods to monitor parameters or phenomena related to the dynamic ocean environment; and deals specifically with new techniques and findings of marine atmospheric boundary layer observations. Advances in SAR Remote Sensing of Oceans is a very comprehensive and up-to-date reference intended for use by graduate students, researchers, practitioners, and R&D engineers working in the vibrant field of oceans, interested to understand how SAR remote sensing can support oceanography research and applications.
Book Synopsis Bulk Wave Property Measurements Using X-band Radar in a Coastal Environment by : Jonathan Andrew Andrechik
Download or read book Bulk Wave Property Measurements Using X-band Radar in a Coastal Environment written by Jonathan Andrew Andrechik and published by . This book was released on 2007 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Depth Estimation and Frontal Imaging Via X-band Marine Radar by : David Andrew Honegger
Download or read book Depth Estimation and Frontal Imaging Via X-band Marine Radar written by David Andrew Honegger and published by . This book was released on 2015 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation focuses on two core aspects of remote sensing: (a) interpretation of the remotely sensed data to identify and characterize sea surface features of interest, and (b) the quantitative analysis of previously characterized features to produce robust estimates of geophysical variables. Specifically, these aspects are addressed in the context of the nearshore coastal ocean, utilizing a land-based, imaging X-band marine radar. With regard to the latter aspect (b), a robust, phase based depth estimate algorithm is extended to marine radar imagery with the purpose of assessing both absolute and relative performance against optical video derived depths. Depth estimates at both a nearby (
Author :United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch Publisher : ISBN 13 : Total Pages :1080 pages Book Rating :4.E/5 ( download)
Book Synopsis Japanese Science and Technology, 1983-1984 by : United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch
Download or read book Japanese Science and Technology, 1983-1984 written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch and published by . This book was released on 1985 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Remote Sensing of Swell and Currents in Coastal Zone by HF Radar by : Weili Wang
Download or read book Remote Sensing of Swell and Currents in Coastal Zone by HF Radar written by Weili Wang and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nearshore marine environment contains many complex processes, but the lack of high-resolution data over a large area during a long time is often the primary obstacle to further research. High-frequency (HF) radar is a mean of remote sensing which obtains continuous near-real time sea surface information over a large area. Thus the study of inversion of marine parameters from HF radar data is very meaningful. Thisthesis makes use of a 13-month-long dataset collected by two phased array HF radar to investigate the characteristics of the sea echo signals, study the data processing and inversion methods, compute sea surface parameters and evaluate the accuracy of radarinversion of swell parameters.The thesis refers to the ground wave HF radar, whose radio waves interact with ocean by Bragg resonance scattering. The development history and applications of HF radar is introduced. The basic theory of electromagnetic wave is reviewed. The principles of inversion of sea surface current, wind direction and swell parameters are described. The feasibility of the swell parameter inversion is investigated. Based on theoretical analysis and statistical studies of a large number of samples, the thesis proposes a series of methods on raw signal processing and quality control, including the determination of the noise level, data averaging in space and time, the proper identification of spectral peaks, the peak width threshold, etc. Respecting the characteristics of different physical processes, inversions of current and wind use spectra collected every 20 min; inversion of swell parameters uses one-hour averaged spectra. The statistics of qualified spectra for swell parameter calculations are presented for both stations. A set of efficient, with a reduced computational cost, automatic computing programs are developed to do the processing and derive marine parameters. Radial current velocities are derived from single radar station. Current vector fields are obtained by combination of both stations. One-year mean flow field in the Iroise Sea is shown, together with the computation of vorticity and divergence. A one-month SeaSonde radar dataset off Qingdao is studied. One-month mean flow pattern together with vorticity and divergence are presented.Relative wind direction with respect to radar look direction is measured through ratio of Bragg peaks amplitudes. Different empirical models are employed to derive radar-inverted relative wind direction. Results show reasonable agreement with model estimations. Different directional distribution models are used to measure the spreading factor for the Iroise Sea. The thesis focuses on the study of swell parameters. Results are validated by buoy and wave model (WAVEWATCH III) data. The assessments show that the accuracy of swell frequency is very good, the accuracy of swell significant waveheight is reasonable, and the accuracy of relative swell direction is low.Consistency of measurements by both radar stations is verified by comparison between the two. This also supports the use of double samples to do the inversion. Use of two radars not only further improves the accuracy but also solves the ambiguity of relative swell direction from single station and gives the absolute wave direction to a certain precision. The thesis proposes a constant relative directionmethod to derive swell significant waveheight, based on the studies of radar integral equation and the inverted results of relative swell direction. This proposal is demonstrated to improve the agreement of radar inversion and buoy/model provided significant waveheight and increases significantly the number of samples. The thesis investigates the accuracy of swell parameters obtained by HF radar. Contributions of random errors in radar observations are quantified. Comparing the differences between radar and buoy/model estimations gives assessments of the contribution of radar intrinsic uncertainty and contribution of other factors.
Book Synopsis Wave-by-Wave Forecasting Via Assimilation of Marine Radar Data by : Alexandra Joyce Simpson
Download or read book Wave-by-Wave Forecasting Via Assimilation of Marine Radar Data written by Alexandra Joyce Simpson and published by . This book was released on 2016 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wave-by-wave forecasting system is desired for optimization of wave energy conversion devices and for improving safety of vessel-based marine operations. This study outlines the first validation attempts of a recently developed forecasting system called Wavecast. The forecasting approach uses X-Band marine radar images for data assimilation, then reconstructs and propagates the ocean wave field in both space and time using the Mild Slope Equation wave model. For data assimilation, the radial component of the sea surface slope is computed from the radar imagery using the recently-derived Radar Model (Lyzenga & Walker, 2015). The Radar Model is a direct relationship between radar backscatter intensity and radial slope, without the need for external calibration. Validation attempts of the forecasting system are carried out in two phases. First, synthetic data is used. Two trials are presented: a simple monochromatic dataset, and a nonlinear simulation of a realistic sea. Results of monochromatic testing show strong spectral correlation, and time series correlation of up to 0.9 throughout the full domain. Results of nonlinear testing show up to 83% spectral correlation of significant wave height, time series correlation up to 0.9 among reconstructed waves, but some decay in correlation among predicted waves. Next a field dataset is presented, which was collected by a ship-mounted radar offshore Newport, OR with spatial and temporal overlap to a TRIAXYS wave profiling buoy. The field dataset provides several challenges. Noise in the electronic compass readings prevented rectification of the ship’s motion; however, this was overcome using a novel post-processing technique on the radar images to georeference each scan without the need for electronic compass readings. Additionally, uncertainty exists in the location of the TRIAXYS buoy; thus, a cross-correlation analysis was performed on a small region surrounding the buoy’s anticipated location to determine the location of maximum correlation between actual and model time series. Despite complexities in the field dataset, assimilation of the field data in Wavecast shows good spectral reconstruction, with issues remaining in time series correlation. The presented validation attempts provide improved understanding of the accuracy and potential of Wavecast, and give support for the validity of the Radar Model.
