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Filipot J.-F.,Service Hydrographique et Oceanographique de la Marine | Ardhuin F.,Service Hydrographique et Oceanographique de la Marine | Babanin A.V.,Swinburne University of Technology
Journal of Geophysical Research: Oceans | Year: 2010

Breaking probabilities and breaking wave height distributions (BWHDs) in deep, intermediate, and shallow water depth are compared, and a generic parameterization is proposed to represent the observed variability of breaking parameters as a function of the nondimensional water depth. In intermediate and deep water, where waves of different scales may have markedly different breaking probabilities, a BWHD as a function of wave frequency is proposed and validated with intermediate-depth and deep water observational data. The current study focuses on waves with frequencies between 0.55 and 3.45 times the peak frequency fp. For the dominant frequency, the integration of the frequency-dependent BWHD provides a breaking probability that reproduces the known threshold-type behavior of the breaking probability for dominant waves. In shallow water, the present breaking statistics parameterization is consistent with other independent formulations validated by shallow water-breaking observations.© 2010 by the American Geophysical Union.


Grant
Agency: European Commission | Branch: H2020 | Program: RIA | Phase: INFRAIA-01-2016-2017 | Award Amount: 10.00M | Year: 2016

The SeaDataNet pan-European infrastructure has been developed by NODCs and major research institutes from 34 countries. Over 100 marine data centres are connected and provide discovery and access to data resources for all European researchers. Moreover, SeaDataNet is a key infrastructure driving several portals of the European Marine Observation and Data network (EMODnet), initiated by EU DG-MARE for Marine Knowledge, MSFD, and Blue Growth. SeaDataNet complements the Copernicus Marine Environmental Monitoring Service (CMEMS), coordinated by EU DG-GROW. However, more effective and convenient access is needed to better support European researchers. The standards, tools and services developed must be reviewed and upgraded to keep pace with demand, such as developments of new sensors, and international and IT standards. Also EMODnet and Copernicus pose extra challenges to boost performance and foster INSPIRE compliance. More data from more data providers must be made available, from European and international research projects and observing programmes. SeaDataCloud aims at considerably advancing SeaDataNet services and increasing their usage, adopting cloud and HPC technology for better performance. More users will be engaged and for longer sessions by including advanced services in a Virtual Research Environment. Researchers will be empowered with a collection of services and tools, tailored to their specific needs, supporting marine research and enabling generation of added-value products. Data concern the wide range of in situ observations and remote sensing data. To have access to the latest cloud technology and facilities, SeaDataNet will cooperate with EUDAT, a network of computing infrastructures that develop and operate a common framework for managing scientific data across Europe. SeaDataCloud will improve services to users and data providers, optimise connecting data centres and streams, and interoperate with other European and international networks.


Grant
Agency: European Commission | Branch: FP7 | Program: CPCSA | Phase: INFRA-2008-1.2.2 | Award Amount: 6.76M | Year: 2009

The overall objective of the Geo-Seas project is to effect a major and significant improvement in the overview and access to marine geological and geophysical data and data-products from national geological surveys and research institutes in Europe by upgrading and interconnecting their present infrastructures.The Geo-Seas partnership has taken a strategic decision to adopt the SeaDataNet interoperability principles, architecture and components wherever possible. This approach allows the Geo-Seas upgrading to gain instant traction and momentum whilst avoiding wasteful duplicative effort. It is envisaged that the SeaDataNet infrastructure will provide a core platform that will be adaptively tuned in order to cater for the specific requirements of the geological and geophysical domains. A range of additional activities for developing and providing new products and services is also undertaken in order to fulfill the diverse needs of end-user communities.


Grant
Agency: European Commission | Branch: FP7 | Program: CP | Phase: SPA.2009.1.1.01 | Award Amount: 4.23M | Year: 2010

Coastal-zone oceanographic predictions seldom appraise the land discharge as a boundary condition. River fluxes are sometimes considered, but neglecting their 3D character, while the distributed continental run-off is not taken into consideration. Moreover, many coastal scale processes, particularly those relevant in geographically restricted domains (coasts with harbours or river mouth areas), are not well parameterized in present simulations. Because of this situation, local predictions still present significant errors and are not robust enough, even being locally wrong for sharp gradient events, such as flash flood discharges into the Mediterranean sea. This hampers decision-making in coastal zones. The FIELD_AC project aims at providing an improved operational service for coastal areas and to generate added value for shelf and regional scale predictions from GMES Marine Core Services. Local assimilation will be analysed together with advanced error metrics to provide a reliable service that can be transferred to public and private parties, using the spin-off company that will result from the project. This will be achieved by the introduction of more comprehensive land boundary conditions, improved local parameterizations and new coupling terms/strategies for the studied field cases. They cover a representative range of meteo-oceanographic drivers for four geometrically restricted domains (Catalan coast, Venice Gulf, Liverpool Bay and the Wadden Sea). FIELD_AC will bridge the gap from shelf predictions to local (river mouth or harbour/beach scales) simulations required at the coastal zone. This will result in a wider demand for operational services and an enhanced use of in-situ and remote observations. Such improvements (services and expertise) will require the advancement of the present state of the art.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-CSA-Infra | Phase: INFRA-2007-2.2-01 | Award Amount: 4.21M | Year: 2008

The Euro-Argo infrastructure will be a major component of the Argo global in situ ocean observatory. The Argo network is a global array of autonomous instruments measuring temperature and salinity over the upper 2000 m of the ocean. Argo is an indispensable component of the Global Ocean Observing System required to understand and monitor the role of the ocean in the Earths climate system. Argo must be considered in its ensemble: not only the instruments, but also the logistics necessary for their preparation and deployments, field operations, the associated data streams and data centres. Euro-Argo will develop and progressively consolidate the European component of the global network. Specific European interest also requires a somewhat increased sampling in regional seas. Overall, the Euro-Argo infrastructure should comprise 800 floats in operation at any given time. The maintenance of such an array would require Europe to deploy about 250 floats per year. The main objective of the Euro-Argo preparatory phase will be to undertake the preparatory work needed to ensure that by 2010 Europe will be able to deploy and operate an array of 800 floats and to provide a world-level service to the research (climate) and environment monitoring (e.g. GMES) communities. The proposal will consolidate and broaden the European participation in Argo and will develop further a leading role of Europe in global ocean observations and in ocean and climate research. The main expected outcome of the proposal is an agreement between member states and other funding agencies for long term (> 10 years) operation of Euro-Argo. To reach such an agreement, it will be necessary to work on several key technical (float technology, data management and delivery system) and organizational (logistics for deployment, coordination of national contributions) issues, to consolidate and broaden the user community and to demonstrate further the impact and utility of the infrastructure for Europe.


Pastol Y.,Service Hydrographique et Oceanographique de la Marine
Journal of Coastal Research | Year: 2011

Starting in 2005, the French Naval Hydrographic and Oceanographic Office (Service Hydrographique et Océanographique de la Marine [SHOM]) and the French National Geographic Institute (Institut Géographique National [IGN]) began conducting a series of coastal surveys using airborne light detection and ranging (LIDAR) bathymetry (ALB) and topographic LIDAR technologies. This paper describes SHOM's experience using ALB in very shallow coastal waters and under challenging hydrographic survey conditions. The performance of ALB in comparison to multibeam echosounder (MBES) and topographic LIDAR surveys is discussed. Further, a procedure is described for integrating ALB data sets from SHOM with topographic data sets from IGN. Recommendations on conducting future survey operations are provided in this paper based on the experience gained and lessons learned. Based on these experiences, SHOM and IGN have begun a national survey project on mapping the coastal areas (sea and land) of France. © 2011 Coastal Education and Research Foundation.


Delpey M.T.,Service Hydrographique et Oceanographique de la Marine | Ardhuin F.,Service Hydrographique et Oceanographique de la Marine | Collard F.,French Research Institute for Exploitation of the Sea | Chapron B.,Collecte Localisation Satellites
Journal of Geophysical Research: Oceans | Year: 2010

The space-time structure of long-period ocean swell fields is investigated, with particular attention given to features in the direction orthogonal to the propagation direction. This study combines space-borne synthetic aperture radar (SAR) data with numerical model hindcasts and time series recorded by in situ instruments. In each data set the swell field is defined by a common storm source. The correlation of swell height time series is very high along a single great circle path with a time shift given by the deep water dispersion relation of the dominant swells. This correlation is also high for locations situated on different great circles in entire ocean basins. Given the Earth radius R, we define the distance from the source R and the transversal angle β so α that and would be equal the colatitude and longitude for a storm centered on the North Pole. Outside of land influence, the swell height field at time t, Hss(β, α, t) is well approximated by a function Hss,0(t - R/Cg) (α sin (α) times another function r2 (β), where Cg is a representative group speed. Here r2 (β) derived from SAR data is very broad, with a width at half the maximum that is larger than 70, and varies significantly from storm to storm. Land shadows introduce further modifications so that in general r2 is a function of and . This separation of variables and the smoothness of the Hss field, allows the estimation of the full field of Hss from sparse measurements, such as wave mode SAR data, combined with one time series, such as that provided by a single buoy. A first crude estimation of a synthetic Hss field based on this principle already shows that swell hindcasts and forecasts can be improved by assimilating such synthetic observations. © 2010 by the American Geophysical Union.


Filipot J.-F.,Service Hydrographique et Oceanographique de la Marine | Ardhuin F.,French Research Institute for Exploitation of the Sea
Journal of Geophysical Research: Oceans | Year: 2012

A new wave-breaking dissipation parameterization designed for phase-averaged spectral wave models is presented. It combines wave breaking basic physical quantities, namely, the breaking probability and the dissipation rate per unit area. The energy lost by waves is first explicitly calculated in physical space before being distributed over the relevant spectral components. The transition from deep to shallow water is made possible by using a dissipation rate per unit area of breaking waves that varies with the wave height, wavelength and water depth. This parameterization is implemented in the WAVEWATCH III modeling framework, which is applied to a wide range of conditions and scales, from the global ocean to the beach scale. Wave height, peak and mean periods, and spectral data are validated using in situ and remote sensing data. Model errors are comparable to those of other specialized deep or shallow water parameterizations. This work shows that it is possible to have a seamless parameterization from the deep ocean to the surf zone. © 2012 by the American Geophysical Union.


Rossi V.,CNRS Geophysical Research and Oceanographic Laboratory | Morel Y.,Service Hydrographique et Oceanographique de la Marine | Garcon V.,CNRS Geophysical Research and Oceanographic Laboratory
Ocean Modelling | Year: 2010

In this paper, the authors study the influence of the wind on the dynamics of the continental shelf and margin, in particular the formation of a secondary upwelling (or downwelling) front along the shelf break. Observations during the MOUTON2007 campaign at sea along the Portuguese coast in summer 2007 reveal the presence of several upwelling fronts, one being located near the shelf break. All upwellings are characterized by deep cold waters close to or reaching the surface and with high chlorophyll concentrations. Simplified numerical models are built in order to study a possible physical mechanism behind this observation. First, a simple shallow water model with three distinct layers is used to study the formation of secondary upwelling fronts. We show that the physical mechanism behind this process is associated with onshore transport of high potential vorticity anomalies of the shelf for upwelling favorable conditions. Sensitivity studies to bottom friction, shelf width, continental slope steepness, shelf "length" are analysed in terms of potential vorticity dynamics. In particular bottom friction is analyzed in detail and we find that, even though bottom friction limits the barotropic velocity field, it enhances the cross-shore circulation, so that no steady state is possible when stratification is taken into account. Bottom friction accelerates the onshore advection of high potential vorticity, but also drastically reduces its amplitude because of diabatic effects. The net effect of bottom friction is to reduce the secondary upwelling development. Based on similar mechanisms, previous results are then extended to downwelling favorable conditions. Finally a more realistic configuration, with bottom topography, wind forcing and stratification set up from observations, is then developed and the results confronted to the observations. Simulations overestimate the velocity amplitude but exhibit good agreement in terms of density ranges brought over the shelf and general isopycnal patterns. The application and extension of the results to more general oceanic regions is discussed and we conclude on the influence of such process on the dynamics of wind driven circulation over a shelf. © 2009 Elsevier Ltd. All rights reserved.


Le Henaff M.,University of Miami | Kourafalou V.H.,University of Miami | Morel Y.,Service Hydrographique et Oceanographique de la Marine | Morel Y.,CNRS Geophysical Research and Oceanographic Laboratory | Srinivasan A.,University of Miami
Journal of Geophysical Research: Oceans | Year: 2012

The dynamics associated with the Loop Current (LC) variability in the Gulf of Mexico (GoM) are studied using a 5-year, free-running numerical simulation with the Hybrid Coordinate Ocean Model (HYCOM). The dynamics of major GoM circulation features are represented: the extension of the LC and the associated anticyclonic, warm core Loop Current Eddies (LCEs) and cyclonic Loop Current Frontal Eddies (LCFEs). The study focuses on the dynamics of the LCFEs and their role during the LCEs shedding, which dramatically affects the GoM circulation. We analyze several characteristics of the LC frontal dynamics. Modeled LCFEs have a coherent vertical structure, which extends to the deep layers of the GoM. They may split in two separate upper and lower layer eddies. Deep and surface remnants from different frontal eddies are able to align to form new, coherent structures. LCFEs intensify along the extended LC northern edge when flowing over the deep northern GoM shelf slope that forms the Mississippi Fan, through a "promontory effect" in which the incoming cyclone aggregates positive potential vorticity anomalies in lower layers, leading to the intensification of the whole vortex structure. LCFEs may also expand further along the LC path by horizontal vortex merging, when they are blocked between the LC and the northeast corner of the continental shelf in the GoM. The intensification and merging due to topographic effects explain the enlarged frontal eddies observed on the eastern side of the Loop Current. These larger eddies further migrate along the LC front and may play a role in the shedding sequence. Copyright © 2012 by the American Geophysical Union.

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