Radar Measurement of Ocean Waves

2011 ◽  
Author(s):  
W. Rob Story ◽  
Thomas C. Fu ◽  
Erin E. Hackett
Keyword(s):  
Ocean Waves ◽  
Lessons Learned ◽  
Sea Surface ◽  
Naval Research ◽  
Sea Clutter ◽  
Analysis Techniques ◽  
Radar Images ◽  
Sea Surface Topography ◽  
Radar Systems ◽  
Wave Radar

Over the past two decades a number of advances have been made in the use of radar systems for the measurement of ocean waves, building on early work at universities and the Naval Research Lab (NRL) to investigate the potential for extracting wave field measurements from the sea clutter seen in shipboard radar images. This early work was the foundation for modern wave radar systems, with hardware systems ranging from commercial off the shelf (COTS) incoherent navigation radar to specially developed, calibrated, coherent instrumentation radar and phased-array systems. Software algorithms and image analysis techniques have also been in constant development, which have evolved from 2D analysis of digitized images into modern techniques performing real-time 3D transformation of high resolution images. Most of these systems are being utilized to measure the directional wave spectra, with some systems also providing wave height estimates and sea surface elevation maps. More recently, the Naval Surface Warfare Center, Carderock Division (NSWCCD) and others have begun to utilize these techniques for shipboard measurement of open ocean waves. All these efforts have led to higher fidelity data, as well as data that were previously unobtainable. In this paper we provide an overview and history of the development of COTS incoherent wave radar systems, analysis techniques, and capabilities, from early characterization of sea clutter return to the latest developments in image inversion and sea surface topography. This review and summary provides a foundation on which to develop analysis techniques for the higher fidelity data, using lessons learned to improve future analysis. While not intending to be exhaustive, this paper seeks to highlight the insights gained from both historical and recent applications of these techniques, as well as the difficulties and issues associated with shipboard measurements such as ship motion, logistical constraints, and environmental factors.

X-Band Radar as a Tool to Determine Spectral and Single Wave Properties

2006 ◽  
Author(s):  
Konstanze Reichert ◽  
Katrin Hessner ◽  
Jens Dannenberg ◽  
Ina Traenkmann
Keyword(s):  
Real Time ◽  
Ocean Waves ◽  
Sea Surface ◽  
Surface Elevation ◽  
Radar Signal ◽  
Sea State ◽  
Single Wave ◽  
Radar Images ◽  
X Band ◽  
Wave Properties

The Wave Monitoring System WaMoS II was developed for real time measurements of directional ocean waves spectra to monitor the sea state from fixed platforms in deep water or coastal areas as well as from moving vessels. The system is based on a standard marine X-Band radar used for navigation and ship traffic control. WaMoS II digitises the analogous radar signal and analyses the sea clutter information to obtain directional wave spectra from the sea surface in real time even under harsh weather conditions and during night. Spectral sea state parameters such as significant wave height, peak wave period and peak wave direction both for wind sea and swell are derived. Within the EU funded project ‘MaxWave’ and the German project ‘SinSee’ new algorithms were developed to determine sea surface elevation maps from radar images which are used to investigate the spatial and temporal evolution of single waves simultaneously. In this paper a short overview describes the calculation of surface elevation maps and the detection of individual waves. Considering two case studies, the results of spatial single wave detection and corresponding temporal single wave properties are compared and discussed. Individual wave parameters derived from radar images are compared to individual waves measured by a buoy. An application of the method to characterise extreme sea states is discussed.

Shipboard Measurement of Ocean Waves

2011 ◽  
Author(s):  
Thomas C. Fu ◽  
Anne M. Fullerton ◽  
Erin E. Hackett ◽  
Craig Merrill
Keyword(s):  
Field Tests ◽  
Ocean Waves ◽  
Naval Research ◽  
Wave Spectra ◽  
Individual Measurement ◽  
Office Of Naval Research ◽  
Wave Radar ◽  
New Instrumentation ◽  
Directional Wave ◽  
Commercial Off The Shelf

Over the past several years a number of techniques have been utilized for the measurement of ocean waves from shipboard platforms. These systems have ranged from commercial off the shelf (COTS) navigation radar and Light Detection and Ranging (LIDAR) systems to specially developed in-house instrumentation systems. Most of these systems have been utilized to measure the directional wave spectra around the ship. More recently, the Naval Surface Warfare Center, Carderock Division (NSWCCD) and others have begun to utilize these techniques for shipboard measurement of individual ship generated waves as well as open ocean waves. NSWCCD has used a number of these methods on various Office of Naval Research (ONR) and Naval Sea Systems (NAVSEA) sponsored field tests. These field tests were performed on a variety of naval platforms over a range of sizes, including some fixed platforms, for various sea states. While each of these tests has had individual measurement goals and objectives, the series of tests has also provided an environment for testing and developing new instrumentation and exploring their capabilities. As a result of these efforts, instrumentation has grown in sophistication from qualitative video-based observations of the wave field around an underway vessel to laser and radar based imaging and ranging measurements of free surface dynamics. This work has led to higher fidelity data, as well as data that were previously unobtainable. In this paper we provide an overview of these systems and techniques and summarize the basic capabilities of each method by providing measurement examples/applications. These systems include a shipboard array of ultrasonic distance sensors for measuring directional wave spectra, a COTS wave radar system, and a COTS scanning LIDAR system. While not intending to be exhaustive, this paper seeks to highlight the insights gained from the recent applications of these techniques, as well as the difficulties and issues associated with shipboard measurements such as ship motion and logistical constraints.

scholarly journals Ocean Wave Measurement Using Short-Range K-Band Narrow Beam Continuous Wave Radar

2018 ◽  
Vol 10 (8) ◽  
pp. 1242 ◽  
Author(s):  
Jian Cui ◽  
Ralf Bachmayer ◽  
Brad deYoung ◽  
Weimin Huang
Keyword(s):  
Short Range ◽  
Continuous Wave ◽  
Ocean Waves ◽  
Sea Surface ◽  
Ocean Wave ◽  
Narrow Beam ◽  
Wave Measurement ◽  
Wave Radar ◽  
Wave Orbital Velocity ◽  
K Band

We describe a technique to measure ocean wave period, height and direction. The technique is based on the characteristics of transmission and backscattering of short-range K-band narrow beam continuous wave radar at the sea surface. The short-range K-band radar transmits and receives continuous signals close to the sea surface at a low-grazing angle. By sensing the motions of a dominant facet at the sea surface that strongly scatters signals back and is located directly in front of the radar, the wave orbital velocity can be measured from the Doppler shift of the received radar signal. The period, height and direction of ocean wave are determined from the relationships among wave orbital velocity, ocean wave characteristics and the Doppler shift. Numerical simulations were performed to validate that the dominant facet exists and ocean waves are measured by sensing its motion. Validation experiments were conducted in a wave tank to verify the feasibility of the proposed ocean wave measurement method. The results of simulations and experiments demonstrate the effectiveness of the short-range K-band narrow beam continuous wave radar for the measurement of ocean waves.

scholarly journals Sea surface topography reconstruction from X-band radar images

2008 ◽  
Vol 19 ◽  
pp. 83-86 ◽  
Author(s):  
F. Serafino ◽  
C. Lugni ◽  
F. Soldovieri
Keyword(s):  
Sea Surface ◽  
State Monitoring ◽  
Sea State ◽  
Radar Images ◽  
Sea Surface Topography ◽  
X Band ◽  
Sea Current ◽  
Global Vision ◽  
Inversion Procedure

Abstract. The paper deals with the feasibility study of the sea state monitoring starting from X-band radar images. The exploitation of radar images allows to achieve a global vision of the sea state compared to the local vision given by the usual sensors as the buoys. The processing approach is based on the formulation of problem as an inverse one where starting from the electromagnetic field backscattered by the sea surface, the information about the sea state are retrieved. The reliability of the inversion procedure is shown by processing synthetic and experimental data where particular attention is focussed to the determination of the sea current and speed of the vessel.

Analyse of Sea Clutter for HF over the Horizon Hybrid Sky-surface Wave Radar

2011 ◽  
Vol 33 (8) ◽  
pp. 1786-1791 ◽  
Author(s):  
Wei Jiang ◽  
Wei-bo Deng ◽  
Qiang Yang
Keyword(s):  
Surface Wave ◽  
Sea Clutter ◽  
Wave Radar

A Deterministic Sea-Clutter Space–Time Model Based on Physical Sea Surface

2016 ◽  
Vol 54 (11) ◽  
pp. 6659-6673 ◽  
Author(s):  
Zhihui Xin ◽  
Guisheng Liao ◽  
Zhiwei Yang ◽  
Yuhong Zhang ◽  
Hongxing Dang
Keyword(s):  
Space Time ◽  
Sea Surface ◽  
Sea Clutter ◽  
Time Model ◽  
Model Based ◽  
Space Time Model

A Fast Generation Algorithm of Radar Images for Ships on Time-evolving Sea Surface

2021 ◽  
Author(s):  
Dandan Gu ◽  
Pengcheng Gao ◽  
Zhijie Xie ◽  
Wei Gao ◽  
Yan Du ◽  
...  
Keyword(s):  
Sea Surface ◽  
Generation Algorithm ◽  
Radar Images

Towards Nonlinear Wave Reconstruction and Prediction From Synthetic Radar Images

2016 ◽  
Author(s):  
A. P. Wijaya
Keyword(s):  
Vertical Direction ◽  
Sea Surface ◽  
Sea State ◽  
Operational Effectiveness ◽  
State Reconstruction ◽  
Radar Images ◽  
First Results ◽  
Marine Radar ◽  
Offshore Activities

The use of remotely wave sensing by a marine radar is increasingly needed to provide wave information for the sake of safety and operational effectiveness in many offshore activities. Reconstruction of radar images needs to be carried out since radar images are a poor representation of the sea surface elevation: effects like shadowing and tilt determine the backscattered intensity of the images. In [1], the sea state reconstruction and wave propagation to the radar has been tackled successfully for synthetic radar images of linear seas, except for a scaling in the vertical direction. The determination of the significant wave height from the shadowed images only has been described in [2]. This paper will summarize these methods, and provides the first results for the extension to nonlinear seas.

scholarly journals Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

Ocean Science ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 311-329 ◽  
Author(s):  
R. A. Ibrayev ◽  
E. Özsoy ◽  
C. Schrum ◽  
H. İ. Sur
Keyword(s):  
Sea Level ◽  
Wind Stress ◽  
Caspian Sea ◽  
Seasonal Cycle ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Sea Surface ◽  
Coastal Currents ◽  
The Caspian Sea ◽  
Sea Surface Topography

Abstract. A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December–January; Eckman south-, south-westward drift in February–July embedded by western and eastern southward coastal currents and transition type in August–November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. The model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

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