Abstract This study comprises the analysis and interpretation of coherent noncoherent parts a coherent-on-receive microwave radar at grazing incidence conditions. The Doppler measurement is an extension standard civil marine technology. While intensity images require based on understanding underlying imaging mechanism, signal measures motion area sea surface therefore closely related to wave physics. Both measured backscatter are suitable for inversion give almost identical elevations. A...

Abstract DYPIC – Dynamic Positioning in ICE - is an international research and development project partially financed by the national agencies of Germany, Norway France. This 3-years initiative (2010–2012) focused on (DP) technology for Arctic environment. The projects' backbone was formed two extensive experimental campaigns performed 2011 2012. paper summarizes work within spotlights technical scientific findings emerged from it. Special attention payed to facets project: design devices,...

Abstract We investigate how the extreme wave statistics of a combined windsea and swell appears to be different from corresponding partitions. consider situation following long-crested in laboratory experiments simulations using high-order spectral method (HOSM). also short-crested crossing at nearly right angle, sea state when Prestige accident happened, hindcast with HOSM. For cases two systems do not interact much, system more Gaussian than partitioned systems, consistent central limit...

Extreme wave statistics of unidirectional and counter-propagating seas are investigated, for the special case long-crested irregular waves, with laboratory experiments numerical simulations using higher order spectral method. Both kurtosis surface elevation exceedance probability crest height larger in than seas. Numerical show that even a small amount energy travelling against an essentially system can significantly reduce elevation.

This study focuses on improving the accuracy of energy distribution in directional wave spectra from temporal sequences marine radar images.Wave are obtained by converting image spectrum to a employing modulation transfer function (MTF).While imaging mechanism plane beam has received much attention, e ect combination di erent positions been largely neglected.Herein, we demonstrate that any MTF can only be valid for limited azimuthal coverage.However, proposed is well suited small windows...

The work analyses the error in current retrievals from images of marine radars. study is based on simulations waves interacting with a shear current. measured dispersion related to underlying wavenumber-dependent effective highest tested radar antenna (H=45 m) vertical polarization performed best. For that case root mean square was at most 0.05 m/s above one for simulated wave field without imaging mechanism. observation time 20 minutes compared shorter windows. Depending needed accuracy,...

This work introduces the deconvolution as a technique to reconstruct missing information in data. While method was originally developed for ocean waves, it will be useful wider range of applications where gaps data may alter statistics or spikes have eliminated without removing extreme values. For application is estimated that long half peak period reconstructed well. It possible longer gaps, however, total amount points should less than 50% all and not clustered.

Abstract We propose a methodology for despiking ocean surface wave time series based on Bayesian approach to data-driven learning known as Gaussian process (GP) regression. show that GP regression can be used both robust detection of erroneous measurements and interpolation over missing values, while also obtaining measure the uncertainty associated with these operations. In comparison recent dynamical phase space–based method, our is here shown lead improved signal correlation spectral tail...

At the Helmholtz Zentrum Geesthacht (HZG), Germany an oceanic monitoring system, based on a Dopplerized microwave radar was developed. Within this paper we present capabilities of system to measure ocean surface wave properties such as significant height, peak period, lengths well other spectral parameters. In addition, is able detect breaking, shear stress wind field, near-surface currents, and bathymetry in shallow water areas. Because diversity measurement capabilities, particularly...

The present paper presents research results from the IceStruct Joint Industry Project (Det Norske Veritas, 2012), in which a simplified methodology for determining characteristic ice load effects on floating and fixed structures was developed. calibrated to of probabilistic model work presented herein describes how mooring line tension spar located an environment with drifting level ridges determined. includes description several stochastic variables (ice ridge keel depth, consolidated layer...

The study analyzes the microwave imaging of shoaling nearshore surface gravity waves during process steepening and breaking over two beaches for a wide range environmental conditions. Data are sourced from coherent X–band radars, operating under low grazing angle Using automatic wave tracking on radar images, evolution individual is followed hundreds meters. extracted backscatter intensity Doppler speed form distinct patterns that reveal non-negligible dependence Statistical representations...

An improved understanding of wave breaking is still a hot topic owing to its relevance in the coupling ocean and atmosphere. Multiple communities are focusing on numerical simulations fully coupled two-phase flow, validation such models remains challenging. Herein, we demonstrate how coherent marine radars can help shed light different wind parameters influence evolution waves towards nearshore. The interpretation results undermined by SWASH shoaling for spectra two beaches radvarimages...

This study focuses on improving the accuracy of energy distribution in directional wave spectra from temporal sequences marine radar images. Wave are obtained by converting image spectrum to a employing modulation transfer function (MTF). While imaging mechanism plane beam has received much attention, effect combination different positions been largely neglected. Herein, we demonstrate that any MTF can only be valid for limited azimuthal coverage. However, proposed is well suited small...

Observations of nearshore waves and wave breaking with two different coherent radars at X-band beaches are presented compared. These were mostly under low grazing angle conditions, a wide span wind including varying steepness, dispersion degree non-linearity, as well non-breaking waves. While some these data has been before, the present work offers unique perspective in comparing observations, which could allow an improved understanding effect environmental conditions system parameters, long...

<p>The work introduces the directional modulation transfer function (MTF) to improve estimate of direction wave spectra from radar images ocean waves. In contrast established MTF, presented MTF better captures distribution energy when spreading is high.</p>

<p>The work introduces the directional modulation transfer function (MTF) to improve estimate of direction wave spectra from radar images ocean waves. In contrast established MTF, presented MTF better captures distribution energy when spreading is high.</p>

We investigate how the extreme wave statistics of a windsea is modified by following swell, means laboratory experiments and simulations using High Order Spectral Method (HOSM) long-crested sea. The spectrum kept equal for all cases, while swell altered. Analysis combined system gives impression that mixed sea has milder than alone, especially when nonlinearities in two systems clearly differ. Upon partitioning into part found to be nearly unaffected governed essentially same irrespective...