Operational oceanography reached a new level with the publication of the first global forecast bulletin by the French group MERCATOR in October 2005. Since then, global ocean fields are available in real time not only for scientific studies but also for commercial or military applications. At a regional scale, the knowledge of the coastal dynamics takes part in key challenges for our society among others the response of the coastal ocean to the global climate changes (extreme events, shore erosion, eutrophication...), marine pollution management or marine security monitoring. However, as for the deep ocean, coastal hydrodynamics models still remain limited in precision due to uncertainties in the atmospheric forcing fields, in the bathymetry solutions or in the boundary conditions prescription for instance. In this framework, data assimilation appears to be a solid and efficient technique to improve the quality of model solutions and the range of forecasts.

Satellites observing systems provide a dense and repetitive network of observations needed for ocean modelling. However, such remote-sensed systems are costly and it is then essential to examine the merits of the available observing configurations in order to find the best compromises between the needs of the scientific community and of socio-economic partners. This poster presents a first prototype of an "End-to- End" Mission Simulator for altimetry. Based on a simplified version of the recently published Ensemble Twin Experiments methodology (Mourre et al., 2006), the simulator aims at quantifying the potential of analtimetry observing system by estimating its ability to reduce the statistical error of a storm surge model of the Bay of Biscay. Relative performance score helps discriminate the various observing scenarios. In the same framework, the simulator is now being adapted for taking into account the tidal signal in the analysis and discriminating process. First results of that specific version of the simulator will also be shown.

In these conditions, it is expected that this "End-to-End" Mission Simulator will constitute a powerful decision-making tool to help CNES in the definition of the future altimetry observing systems.

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Number 117 - Session 4

USING ADVANCED DATA ASSIMILATION FOR ASSESSING THE
CAPABILITIES AND LIMITS OF USING THE GOCE GEOID TO IMPROVE

THE SHELF AND COASTAL OCEAN LOW-FREQUENCY CIRCULATIONS

J. Lamouroux1, P. De Mey2, G. Moreaux1, G. Balmino3, M. Le Hénaff2, M. Lux1, R. Haagmans4,

C. Bouzinac4

1 NOVELTIS, Toulouse, France

2 POC, Toulouse, France

3 GRGS/CNES, Toulouse, France

4 ESA-ESTEC, Nordwijck, The Netherlands

Corresponding author: Julien Lamouroux, julien.lamouroux@noveltis.fr

Abstract

Realistic ocean modelling is part of the new challenges that has arisen in the past decade in order to access precise and accurate knowledge of the ocean circulation, especially at regional and coastal scales. An efficient ocean modelling system is now built both on both a hydrodynamic model and a data assimilation technique. Altimetric data plays a central role because of their relative abundance, coverage and repetitive sampling. At the large scales, using a geostrophic balance equation, the upper-layer ocean circulation could be approximately retrieved from the ocean surface topography, assuming that the ocean surface reference level, given by the geoid, is known with sufficient accuracy. However the geoid solutions do not contain the smaller scales characterizing coastal dynamics. More generally, the lack of control over the permanent circulations is a serious limitation for the regional ocean modelling and forecasting.

The need for better ocean geoids has then been identified for a long time, and the recent gravimetric satellite missions are a first step to solve the problem. The GOCE satellite, developed at ESA and scheduled for liftoff in September 2008, will operate between two and two and a half years. Its main objective is to further improve our knowledge of the geopotential in providing a higher resolution static model for a variety of applications, especially in oceanography. The scientific community expects that the improved geoid model from GOCE will significantly advance our skill at modelling the mean ocean circulation, by using (1) precise geocentric sea surface elevations obtained from global altimetric measurements, (2) a mean geoid model with an accuracy of the order of one centimeter on spatial scales down to the width of boundary currents, (3) additional oceanographic data sets required to constrain ocean circulation models with data assimilation.

The study presented here aims to assess the capabilities and the limits of the use of the GOCE geoid to improve the shelf and coastal ocean low frequency circulations. The approach consists in using advanced data assimilation techniques (namely, the Ensemble Kalman Filter analysis kernel from the SEQUOIABELUGA data assimilation platform ? De Mey, 2008, pers. comm.) in a hydrodynamic model to estimate the expected benefit of using GOCE data in addition to altimetric data. We use the SYMPHONIE 3 D freesurface model (Marsaleix et al., 2008), implemented on the Bay of Biscay; the dynamics features a strong topographically-steered slope current, characterised by an associated mesoscale activity inducing strong exchanges between the shelf and the abyssal plain. In the framework of OSSEs, direct assimilation experiments of simulated altimetry and GOCE data are currently set-up with the Ensemble Kalman filter. In a first step, GOCE geoid error covariances are produced. We then look at the impact of simulated GOCE data onto the topographically-steered flow at the shelf break and its associated mesoscale and submesoscale field, and examine whether, if we assimilate GOCE data, those dynamical features and associated cross-slope transports are closer to the "truth".

 

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Number 76 - Session 3

 

TOWARD CLIMATIC HIGH RESOLUTION COASTAL AND SHELF MODELLING: IMPACT OF RESOLVING THE DIURNAL CYCLE

C. Langlsis1, B. Barnier2, P. Fraunie3

1UTAS, CSIRO, HOBART, TAS Australia

2LEGI, Grenoble, France

3LSEET, Toulon, France

Abstract

Shelf modelling is an actual important challenge. In term of ocean forecasts, shelf modelling is necessary if we want to extend the predictability of the global operational systems towards coastal and regional sub-systems. And on another hand, climatic shelf reanalysis are also crucial to understand the actual global climatic change because the exchanges at the shelf breaks are important source terms which need to be taken into account at a global scale.

The paper deals with a regional model of the continental shelf of Gulf of Lions. The model based on the NEMO code is designed to study the physical processes at the shelf edge and the exchanges between the shelf and the open ocean during a quasi-climatic period of 11 years (1990-2000). Its horizontal resolution is 1/64° and it has 130 vertical levels. Conditions at the limits of the regional model are handled by radiative open boundary conditions. The data are provided every 5 days by a global, high resolution (1/16°) ocean circulation model of the whole Mediterranean Sea driven with ERA40 [Mercator project, Béranger et al.]. The atmospheric forcing is provided hourly at 18km resolution by a dynamical downscaling of ECMWF re-analysis ERA15 with the regional atmospheric model REMO [Jacob et al., 2001], and bulk formulations are used to couple the atmosphere and the ocean.

In a shelf area like the Gulf of Lions dominated by highly variable coastal processes, the resolution in space and time of the forcing data sets is an important requirement to obtain realistic results. On the shelf, if the low frequency seasonal variability dominates the coastal hydrology, the high frequency variability is driven by the wind forcing which acts at time scales of few hours on the oscillating motions and internal waves and at a time scale of a few days on the upwelling/downwelling system. The diurnal solar cycle is also shown to introduce a diurnal variation of the temperature in the upper layers and to modify the structure of the turbulent mixed layer. In this paper we will study the impact of resolving the diurnal cycle. If it improves the realism of the simulation by introducing high frequency ocean mechanisms, it also modifies the air-sea fluxes and in particular the exchange of heat between the atmosphere and the ocean. The diurnal variations of SST modify the time-mean net heat flux which enter the ocean and then modify the heat content in the upper ocean.

 

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Number 78 - Session 3

 

C. Langlais1, 2, A. Schiller3, R. Coleman2

1CSIRO CMAR (WfO Flagship Program), Hobart, TAS Australia

2UTAS, Hobart, TAS Australia

3CSIRO CAWCR, (WfO Flagship Program), Hobart, TAS Australia

Abstract

The Bluelink Ocean ReAnalysis (BRAN) is part of a global short-range operational forecasting system (http://www.bom.gov.au/oceanography/projects/BLUElink/index.html). BRAN is a multi-year model integration and through assimilations ocean observations, it provides an integral view of the ocean dynamics in the Asian-Australian region for the period October 1992 to June 2006. The eddy-resolving system has been evaluated in the sub-domain of the South-East Asian region (Schiller et al., 2008). But the dynamics of the Southern Ocean has not yet been studied in detail.

The global eddy-resolving ocean circulation model is based on version 4.0 of the Modular Ocean Model (Griffies et al., 2004) with a 1/10° horizontal resolution around Australia (90-180°E, 16°N-75°S) decreasing until 2° in the North Atlantic Ocean and 47 vertical levels. The atmospheric forcing is provided every 6 hours by the ERA40 reanalysis of ECMWF. All available remotely sensed and in-situ observations in the region are assimilated: altimetric sea level anomaly, satellite SST, coastal tide gauges and quality-controlled in situ temperature and salinity profiles from a range of sources including field surveys and the Argo float array.

In the Southern Ocean, circumpolar density fronts constitute robust and continuous features which are associated with the jets of the Antarctic Circumpolar Current (ACC).Those fronts are very persistent and coincide with particular water mass features. The same simple phenomenological criteria can be used to locate the fronts along their circumpolar extent. However, the multiple jets of the ACC are often shown to merge and diverge and change in intensity across the Australian sector, mainly due to interactions with topography. Sokolov and Rintoul (2007) reconciled the two disparate views and showed that alignment between the multiple branches and the streamlines persist and is robust, surviving despite vigorous interactions between the mean flow, eddy field and topography. Following this description, we will evaluate the complex structure of the Southern Ocean in the BRAN reanalysis and in the spin up run (with no data assimilation).

 

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Number 155 - Session 3

 

G. Larnicol, S. Guinehut, M. H. Rio, A.-L. Dhomps, G. Nicolas

CLS, Space Oceanography Division, Ramonville, France

 

Abstract

 

Producing comprehensive information about the ocean has become a top priority to monitor and predict the ocean and climate changes. Complementary to the modelling/assimilation approach, an observed based approach based on the combination all the observations provided by the Global Ocean Observing System (altimetry, sea surface temperature, temperature and salinity profiles, drifters,?) is proposed here. It consists to produce Global Observed Ocean Products (GooP) corresponding to 3D fields of temperature, salinity and velocity from the surface down to 1500m. In practice, three kinds of products are generated. First, accurate but sparse in-situ T/S profiles data are merged with high resolution altimeter and SST data in order to reconstruct global instantaneous thermohaline fields from the surface down to 1500 m depth. Second, global instantaneous surface currents are derived from a combination of altimeter geostrophic currents, Ekman currents derived from wind-fields and in-situ surface currents derived from drifting buoys. Thirdly, the combination of the two later products allows us to the retrieve the 3D velocity field.

The first part of the poster will be dedicated to the description of the method. In the second part, Global Observed Ocean Products re-analysis that covers the recent period (1993 to 2007) will be assessed. Interannual variability of the whole ocean will be characterised in term of variation of heat content, transport, weakening or acceleration of the main features of the general circulation. Comparison with existing model re-analysis will be also presented.

 

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Number 156 - Session 4

A. Mignot, M.H. Rio, S. Guinehut, G. Nicolas, G. Larnicol

CLS, Space Oceanography Division, Ramonville, France

 

Abstract

 

Monitor and understand the 3D variability of the North Atlantic Ocean is a key issue for the climate change. In parallel to the classical modelling/assimilation approach, we have developed a method only based on observation analysis. It firstly consists to combine in-situ profiles (ARGO,?) with satellite measurements (sea level anomalies from altimetry and SST) to retrieve the 3D thermohaline fields and then the baroclinic velocity from the surface down to 1500m. Then, the total geostrophic velocity field is obtained by estimating the circulation at 1500m (corresponding to barotropic and deep baroclinic components). This circulation is obtained by combining the total surface velocity observed by altimetry with the velocity deduced from in-situ profiles.

A re-analysis of the 3D velocity field from the surface to 1500m of the North Atlantic was produced for the 1993-2007 period. It was validated thanks to comparison with in-situ velocity measurements (RAFOS) and with a model re-analysis from Mercator-Ocean (MERA-11). Finally, the variability of the North Atlantic was analysed and exhibits a clear decadal variability of the seasonal cycle of the Gulf-stream, a weaking of the subpolar gyre circulation down to 1500 m.

 

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Number 42 - Session 5

 

S. Law Chune1, Y. Drillet2, P. Daniel3 and P. De Mey4

1Mercator Ocean, Toulouse, France

2 Mercator Ocean, Toulouse, France

3Meteo France, Toulouse, France

4LEGOS- CNRS, Toulouse, France

Abstract

Metéo France uses a surface oil spill drift model to assist authorities in charge of marine pollution or search and rescue operations. This system was already successfully used for real cases such as the Erika (1999) or Prestige (2002) incidents or for experimentations in the Mediterranean Sea during Mersea project in 2007.

The drift model, called Mothy, is based on the common work of a limited area ocean model and a hydrocarbon model. A part of the ocean modelling consists in a barotropic approximation which allows a quick execution but strongly limits performances inside non-well mixed or turbulent waters, as in the Mediterranean Sea. Operational oceanography can answer to Mothy needs, those systems represent nowadays state-of the art ocean processing and describe in a realistic way the general oceanic circulation, including the whole of non present oceanic processes in Mothy (large scales current, eddies, etc.). A solution then consists in selecting the current at the base of the oceanic mixed layer of this 3D system and adding this to the current computed by Mothy.

We want to find more satisfying solutions for the integration of Mercator Océan currents in Mothy. In this study, new horizontal current fields have been produced according to Mothy expectation: the geostrophic component of the current, the 2D mean component of the oceanic signal minus mean wind effects, and at last, a spatially and temporally variable current extraction, directly under Ekman depth. The results, in comparison with observation in the Mediterranean Sea, are however encouraging to further tests. The contribution of Mercator Ocean system confirms that the good description of the circulation, in particular the positioning of currents and meso-scale structures, plays a key role in drift applications. The operational systems available at present time have horizontal resolutions about 1/12°, which is not enough to resolves the sub meso-scale processes which have a large impact on the oil spill drift. We will show however that our degree of confidence in such oceanic forcing is better for stable current regime than in turbulent area.

 

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Number 41 - Session 4

 

Olivier Le Galloudec1, Romain Bourdallé-Badie2, Clément Bricaud1, Corinne Dreval2, Yann Drillet1, Edmée, Durand3, Gilles Garric4

1MERCATOR-OCEAN, 31520 Ramonville St Agne, France

2CERFACS, 31057 Toulouse, France

3Météo-France, 31057 Toulouse, France

4MGC 31000 Toulouse, France

Abstract

Mercator-Ocean has developed a new global ocean forecasting system at high resolution (1/12°) based on the

NEMO OGCM. An interannual experiment of 8 years (1999-2006), driven by atmospheric ECMWF analyses has been performed. Evaluation of this eddy resolving experiment through comparisons with in-situ and altimetric data is first discussed. The Gulf Stream, its separation at Cape Hateras and its penetration in the North Atlantic are particularly well simulated. The distribution of the modelled mesoscale variability is in good agreement with altimetric data (cf figure). Areas with high level of energy like in the Aghulas Current, or in the Zapiola anticyclone or in the circumpolar current compare well with satellite altimetric data. The impact of the resolution is also discussed thanks to a comparison made with a twin experiment performed with the NEMO OGCM at the eddy-permitting (1/4°) resolution.

 

 

 

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Number 79 - Session 3

 

ASSESSMENT OF OBSERVATIONAL NETWORKS WITH THE REPRESENTER MATRIX SPECTRA METHOD

- APPLICATION TO A 3D COASTAL MODEL OF THE BAY OF BISCAY

M. Le Hénaff1, P. De Mey1, P. Marsaleix2

1LEGOS,Toulouse, France

2Laboratoire d'Aérologie, Toulouse, France

Abstract

The development of coastal ocean modelling in the recent years has allowed an improved representation of the associated complex physics. Such models have become more realistic, to the point that they can now be used to design observation networks in coastal areas, with the idea that a "good" network is a network that controls model state error. To test this ability without performing data assimilation, we set up a technique called Representer Matrix Spectra (RMS) technique that combines the model state and observation error covariance matrices into a single scaled representer matrix. Examination of the spectrum and the eigenvectors of that matrix informs us on which model state error modes a network can detect, and constrain, amidst the observation error background.

We applied our technique to a 3D coastal model in the Bay of Biscay, with a focus on mesoscale activity, and tested the performance of various altimetry networks and an in situ array deployment strategy. It appears that a single nadir altimeter is not efficient enough at capturing coastal mesoscale physics, while a Wide Swath altimeter would do a much better job. Testing various local in situ array configurations confirms that adding a current-meter to a vertical temperature measurement array improves the detection of secondary variability modes, while shifting the array higher on the shelf break would obviously enhance the model constraint along the coast.

The RMS technique is easily set up and used as a "black box", but the utility of its results is maximized by previous knowledge of model state error physics. The technique provides both quantitative (eigenvalues) and qualitative (eigenvectors) tools to study and compare various network options. The qualitative approach is essential to discard possibly inconsistent modes.

 

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Number 147 - Session 2

 

P.Y. Le Traon1 and the Euro-Argo consortium**

1Ifremer, Centre de Brest, Plouzané, France

**BSH, Germany, KDM, Germany, NERC, United Kingdom, Met Office, United Kingdom, KNMI, Netherlands, IEO, Spain, OGS, Italy, Marine Institute ,Ireland, Institute of Marine Research, Norway, SHOM, France, FFCUL, Portugal, HCMR, ,Greece, IOPAS, Poland, University of Sofia, Bulgaria

Abstract

In November 2007, the international Argo programme reached its initial target of 3,000 profiling floats. These floats measure temperature and salinity throughout the deep global oceans, down to 2,000 metres and deliver data in real time for operational users. This is the first-ever global, in-situ ocean-observing network in the history of oceanography, providing an essential complement to satellite systems. One of Argo's most important contributions so far is a huge improvement in estimations of heat stored by the oceans - a key factor to gauge global warming and gain a better understanding of the mechanisms behind rising mean sea level. Argo has also brought remarkable advances in ocean forecasting and seasonal climate predictions and is giving new insights into hurricane activity. Maintaining the array's size and global coverage in the coming decades is the next challenge for Argo. Around 800 new floats will be required each year to maintain the 3,000 float array.

Euro-Argo will develop and progressively consolidate the European component of the global network. Specific European interests also require increased sampling in some 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. Euro-Argo must be considered in its entirety: not only the instruments, but also the logistics necessary for their preparation and deployment, field operations, the associated data streams and data centres. Euro-Argo was one of the 35 projects selected in 2006 for the European Roadmap for Research Infrastructure by ESFRI. The ESFRI roadmap identifies new Research Infrastructures of pan-European interest corresponding to the long term needs of the European research communities. As a new European research infrastructure, Euro-Argo is starting a preparatory phase funded through the EU 7th Framework Research Programme. The Euro-Argo preparatory phase is coordinated by Ifremer, France. The consortium comprises 15 organisations from 12 European countries. The main objective of the Euro-Argo preparatory phase is to undertake the work needed to ensure that by 2010 Europe will be able to provide, deploy and operate an array of 800 floats contributing to the global array and providing enhanced coverage in the European regional seas, and to provide a world-class service to the research (climate) and environment monitoring (e.g. GMES) communities. Euro-Argo has strong links with operational oceanography and with the development of the GMES Marine Core Service (MCS).

 

 

 

 

 

 

 

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Number 26 - Session 2

 

Daniel J. Lea1, Keith Haines2, Matthew J. Martin1

1Met Office, Exeter, UK

2ESSC, Reading University, UK

 

Abstract

We implement a combined online model and observation bias correction system in the UK Met Office FOAM OI Unified Model ocean data assimilation system. The observation bias scheme is designed to estimate the error in the mean dynamic topography that must be used for altimeter data assimilation. The mean dynamic topography field is added to the altimeter data supplied as sea-level anomalies giving the absolute sea surface height. The bias scheme separately estimates the remaining model bias in the model sea surface height field. The final unbiased estimate of the absolute dynamic topography is assimilated into the FOAM model by adjusting the subsurface density field using the Cooper and Haines scheme. Various diagnostics including the observation minus background statistics show that both model and observation bias correction schemes improve the assimilation results. Combining the schemes provides better results than either alone.

The FOAM system is now transitioning from the Unified Model ocean to a 0.25 degree global NEMO system using the same OI assimilation scheme. Some results will be presented using the bias correction scheme with this new system.

 

 

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Number 163 - Session 5

 

PREVIMER - COASTAL OBSERVATIONS AND FORECASTS

Fabrice LECORNU, Yann-Hervé DE ROECK, Jacques LEGRAND

Ifremer Centre of Brest, BP 70, 29280 Plouzané - France

 

Abstract

 

Since mid-2006, PREVIMER website, www.previmer.org, provides information relevant to the general public and the professionals about the coastal environment, along the French coastlines bordering the English Channel, the Atlantic Ocean, and the Mediterranean Sea. In the initial phase (2006-2007) of this pre-operational system, observation data and numerical modelling contribute to the production of 48-hour forecasts of sea states, currents, sea water levels and temperatures. Scales range from the continental shelf to the bay, with a capacity for zooming-in to specific areas. An increasing number of biological parameters is gradually completing this overview of coastal environment, and a 5-day forecast is already available on some sea state variables.

The emphasis is put on validating the maps produced, and their qualification by experts in the field, leading to the implementation and development of a coastal forecasting service, following the examples of meteorology, and more recently, of oceanic circulation.

PREVIMER already generates modelling results and displays in-situ and remote sensing data on diverse themes, through the following pilot sites:

• English Channel, Bay of Biscay and Western Mediterranean circulation model with an up to 1.2 km resolution and 30 layers, barotropic tide and high-sea boundary conditions from the oceanic global operational system Mercator,
• Circulation and sea-state in Iroise Sea, with a 300m resolution, including a daily automatic forecast bulletin,
• Sanitary quality demonstrator with restricted access for bathing water at Moulin-Blanc beach (Brest, Brittany),
• Primary Production in the Bay of Biscay, showing the fate of nutrients and the major phytoplanktonic blooms, with a special focus along the Brittany coast subjected to some local risks of eutrophication,
• Real time assessment of sediment transport and induced turbidity in the Bay of Vilaine (South Brittany),
• Circulation and coastal-lagoon exchange around Nouméa (New-Caledonia).

PREVIMER also contributes to the R&D of dedicated observation tools (buoys and autonomous sensors, some on ships of opportunity ...) and helps some experimental devices to become operational.

Mixing data and forecast will produce, for numerous marine leisure and activities, various indicators ranging from thematic comfort indices to actual warning maps. The continuous production of synoptic information and analyses builds progressively a coastal climatology, which constitutes a needed database for a rapid and secure detection of anomalies in the physical or biogeochemical environment, and to mitigate their consequences for the marine and maritime business.

PREVIMER, a partnership of public institutions, with the French Naval Hydrographic Office (SHOM), Météo-France, the research institute for the development (IRD), the European Institute of Marine Studies (IUEM) and Brest science and technology park (Technopôle Brest Iroise), is coordinated by IFREMER (the French public institute for marine research), which supplies the technologies needed to ensure this pertinent information, available daily on Internet, and stored at the Operational Coastal Oceanographic Data Centre. Local SME's are strongly contributing to the development of the system, and they are associated for the design of value-added products for various end-users, especially in the second phase of the project (2008-2013).

 

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Number 43 - Session 4

 

Ye Liu 1, 4, Jiang Zhu 2, Jun She3

1International Center for Climate and Environment Sciences(ICCES), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.

2State key Laboratory of Atmospheric Boundary Layer Phyiscs and Atmospheric Chemistry(LAPC), Chinese Academy of Sciences, Beijing, China.

3Centre for Ocean and Ice, Danish Meteorological Institute, Copenhagen, Denmark..

4Graduate University of Chinese Academy of Sciences, Beijing, China.

Abstract

 

In this paper, an anisotropic spatial recursive filter is used to modeling the background error covariance in an oceanic Three-Dimensional Variational (3DVAR) scheme. Different from traditional algorithms of background error, this 3DVAR scheme largely reduces the memory storage required in its implementation since the background error covariance is calculated in a implicate way. Furthermore, by preconditioning the control variable, there is no inversion of the background error covariance in the scheme. With the anisotropic recursive filter, the analysis increments fall off rapidly according to the background error field gradient.

The potential advantage of this new scheme is demonstrated by applying it to analyze the temperature and salinity profiles in North Sea and Baltic Sea area. The comparison with in stu observation data shows that the results produced by the flow-dependent anisotropic spatial recursive filter are significantly better than the results yielded by model directly. The results suggest that the anisotropic recursive filter is effective in the ocean data assimilation, especially in the coastal area.

 

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Number 175 - Session 4

 

Thomas Loubrieu, Mickael Treguer, Lidwine Nonnotte

IFREMER, Plouzane, France

Abstract

At European level, a great effort has been made to set up portals providing homogeneous access to the products of operational oceanography.

These tools, driven by, both, functional requirements and INSPIRE European directive for interoperability of geo-referenced datasets, enable to discover the datasets, to preview and to download them in a pan-European distributed architecture. For the achievement of these functions, developments have been made in the framework of MERSEA and ECOOP projects and will be carried on during MyOcean project (see presentations of J. Blower et al. and F. Blanc et al.).

In the meantime, at the French Marine Institute, IFREMER, the operational oceanography activities (PREVIMER for coastal operational oceanography, CORIOLIS, for in-situ observation management) require the same functions for discovery and preview and download of the products. Besides, support and monitoring for the operational production activities was required.

At European and national level, it was decided to use the same technical platforms and the same standards for doing that.

For the discovery function and monitoring and supporting tools, the same metadata-base called CAMIOON is used. It now contains the description of the products for 4 projects. These metadata are used to monitor the activities of production and are a documentation base for the operation team at IFREMER level. Thanks to the ISO19115/XML standard the metadata can be easily shared with the IFREMER overall catalogue (SEXTANT).

For the preview of the datasets, the OGC/WMS standard has been implemented for operational oceanography products (SEAGRID) at IFREMER. Similar tools are developed in the European context and efforts are carried on to make them fully compliant. Then the dynamically generated previews of datasets can be shared by European and French national systems.

At last, the download access to the datasets is provided at European level and IFREMER's level with the same tools and standards for gridded datasets : they are stored as netCDF files following the CF-convention and the download access is provided through FTP servers (for highly reliable access) or THREDDS Data Server providing OPeNDAP interfaces (for advanced subsetting function). In addition, OGC/WCS is currently under test for doing that. Giving homogeneous access to the raw observations (in-situ profiles, mooring time series, satellite swath?) is the challenge for the coming years. The CSML and UNIDATA/CDM initiatives for defining standard ocean observation feature types are a great support for doing that properly. Their implementation is planned at national level together with European projects (HUMBOLDT).

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Number 142 - Session 2

 

Carlos Lozano, Hendrik Tolman, Avichal Mehra, Hyun-Sook Kim, Robert Grumbine

and David Behringer

Environmental Modeling Center of NCEP/NWS/NOAA, Camp Springs Maryland, USA

 

Abstract

As prediction systems for the Earth are integrated in multi-model ensemble systems, it is of interest to examine the goals and the Methodologies presently used for ocean forecast systems; and examine potential integration strategies for these systems within the Earth model system. The current configuration of operational ocean forecast systems at the National Centers for Environmental Prediction (NCEP) in the United States of America includes an event driven coupled atmosphere-ocean for hurricane prediction; a real-time ocean forecast system for the Atlantic Sector, a global-regional nested grids wave forecast system for a short term prediction; and a climatology forecast system (CFS) with atmosphere, ocean and ice coupled models for a seasonal-to-interannual prediction. A specific description of each system component including data, model and assimilation, will be presented. Plans for future developments in NCEP include two different resolution global ocean models ? 2/25-degree (current NRL global model) and a 1/7-degree; and a CFSRR (Climate Forecast System global Reanalysis and seasonal Reforecast). The latter is an integrated earth system with three core components: 1) analysis system, 2) atmospheric model, and 3) ocean model. The presentation will particularly focus on this Integrated Earth System.

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Number 180 - Session 3

Validation of Global Ocean Models for CONCEPTS

Youyu Lu1, Dan Wright2, Zeliang Wang2, Frederic Dupont2, Greg Holloway2,

Jie Su3, Xu Zhang4, Jean-Marc Belanger1, Francois Roy1, Hal Ritchie1

1Environment Canada

2Fisheries and Oceans Canada

3Ocean University of China

4Nanjing University

Abstract

Ocean models based on the Nucleus for European Modelling of the Ocean (NEMO) are being used in Canada for global, basin and regional applications as contributions to the Canadian Operational Network of Coupled Environmental PredicTion Systems (CONCEPTS). Two global ocean models, with nominal horizontal resolution of 1-degree and ¼-degree in longitude/latitude, are being tested with forcing from atmospheric reanalysis. Initial validation using large-scale ocean observations reveals that the models are able to simulate many key processes and variations in the ocean. These include interannual and decadal changes in hydrography and sea level, the tropical ocean responses associated with the Madden-Julian Oscillation and the El Nino-Southern Oscillation,

Artic sea-ice changes, flow through key channels in the Canadian Arctic Archipelago, the energetics of ocean meso-scale eddies, etc. Initial tests also show that similar ocean forecasts are obtained by using the forecasting fields of the Canadian Meteorological Center and the European Centre for Medium-range Weather Forecasting. The results of the initial validation are encouraging for the development of the coupled atmosphere-ocean forecasting system in Canada. Data assimilation developments are being undertaken in basin-scale formulations. Promising DA developments will be transferred to the global system after initial validation in these reduced domains.