PROTEVS

Ocean Forecasting, Turbidity, Flow, Waves and Sedimentology

by S. Louazel *^(a) 

^{(*) :} Corresponding author : Stéphanie Louazel, louazel@shom.fr 

^{(a) :} SHOM Brest, France

The coastal region of the Atlantic seaboard is the place of intense economic and environmental activities. These interests, combined with a wide geographical opening of the French coast on the open ocean, justify the effort of the scientific community to better understand the physical and biogeochemical ocean processes prevailing there. As such, the PROTEVS  (« PRévision Océanique, Turbidité, Ecoulements, Vagues et Sédimentologie ») project aims to improve the knowledge of the marine environment in real time as well as its possible evolution to meet the needs of the French Navy.

The PROTEVS project is build on a system of regional demonstrators for the prediction of ocean circulation and sea states, previously introduced in operational oceanography projects conducted by the SHOM. These tools are developed on the basis of numerical models of ocean observations, for the purpose of analysis and forecasting in real time.

Funded by the DGA (Direction Générale des Armées) and the French Navy, the project was launched in September 2009 and will end in December 2017. PROTEVS is mainly based on the results of other projects such as MOUTON (Modélisation océanique d’un Théâtre d’Opérations Navales), ECORS (Etude et Caractérisation opérationnelle des routes et des sols) and «Turbidité Océanique ».

Scientific Interest

Initiated in 1997 by the DGA for support forces in the fight under the sea, the SOAP project (Operating System Analysis and Prediction) has achieved its objectives to provide analysis and forecasting parameters (sea state, temperature, salinity) and their transfer to regular operational interested users. With these first oceanographic and acoustic products from SOAP, the project PROTEVS aimed to improve these tools to better understanding the oceanic and coastal processes impacting military operations.

Several processes are of interest in the Atlantic maritime coastal area, including in particular the tidal currents, tidal fronts, the currents generated by the wind, river plumes, formation of warm water masses on the continental shelf, exchanges between the coastal zone and the open sea, including the influence of the Navidad current on the continental shelf and the intrusion of Mediterranean water.

Thus, the numerical modeling of the coastal processes that are very sensitive to environmental parameters is a challenge. An integrated regional system of operational oceanography is built on, with the idea to achieve a continuous oceanic modeling ranging from offshore to coastal areas. With both analysis and forecasting configurations, all the physical processes of oceanic circulation (currents, temperature, salinity) and sea conditions (waves) are progressively coupled with biochemical parameters (suspended solids, soil instability, transparency and visibility) and sediment dynamics in order to achieve a comprehensive understanding of oceanic and coastal processes.

Coupled with numerical modeling efforts, the development of a network of marine observation is also part of the objectives of PROTEVS to ensure the collection of in-situ measurements needed to validate the numerical model outputs.

Methodology

The work plan established for PROTEVS for the development of operational tools is divided into 3 parts:

1. studies of oceanic processes and improvement of the models  : Hydrodynamic modeling tools developed by the SHOM are based on two demonstrators: the first one is HYCOM (Hybrid Coordinate Ocean Model) for current and the second one is WW3 (Wave-Watch-3) for the waves.
2. in situ observations : The validation of model outputs requires the accumulation of diagnostics to improve the global modeling and quantitative aspects of the simulations (for a direct comparison measurements / models). This validation is based on satellite data regarding surface information, and in-situ data for the information on the whole water column. The cruises are conducted for the PROTEVS project to acquire in-situ data to validate the model outputs of ocean circulation and chemistry data for the construction of a biochemistry model in the area of the Biscay English Channel. These campaigns range from 2010 to 2013 and follow campaigns for the MOUTON project carried out from 2004 to 2009. The first two legs were held in spring 2010 ; they have allowed the realization of 460 CTDs, 135 XBTs, 1100 miles of seasoar measurements and the deployment of 23 floats.
3. Development of demonstrators : the two previous steps are tested in four areas of the French Atlantic coast : the English Channel, Bay of Biscay, West Portugal and the Gulf of Cadiz. Their operational capabilities will be assessed by : 

• the realistic comparison between in situ observations and numerical modelling
• the contribution of the assimilation, which is used to correct drifts in the model from in situ and satellite measurements
• evaluate the limits of the demonstrator

The Intranet wesite of the project is updated daily, showing different maps (temperature, salinity, currents etc ...) published  to help operational decisions on the area.

Interesting links

Service Hydrographique et Océanographique de la Marine (SHOM) : http://www.shom.fr

SOAP3 : http://www.shom.fr/fileadmin/data-www/DMI/Fiche_projet/Projet_SOAP_V2_0_FR.pdf

MERCATOR :  http://www.mercator-ocean.fr

PREVIMER : http://www.previmer.org

References

• Assenbaum M., 2005 : Introduction à HYCOM. Technical report, Géosciences.
• Morel, Y., R. Baraille and A. Pichon, 2008 Time splitting and linear stability of the slow part of the barotropic component. OCEAN MODELLING, 23(3-4) :73–81. ISSN 1463-5003
• Pasquet A., 2011 : Etude des mécanismes de dispersion en zone côtière. Application aux fronts tidaux en mer d’Iroise. Thèse de doctorat, Université de Toulouse, décembre 2011, 260 pp.
• Pichon A. and S Correard : Internal tides modelling in the Bay of Biscay. Comparisons with observations. SCIENTIA MARINA, 70 :65–88, 2006.