MERCATOR French Ocean SystemEntry ID: MERCATOR
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Abstract: The Mercator mission was defined in 1996 by six partner organizations (Cnes,
CNRS, Ifremer, IRD, Meteo France, and Shom). Mercator Ocean is based in
Toulouse, France, which acts as the focal point for development work. Today,
the team numbers 30 engineers and researchers from the six partner
organizations, supported by ... subsidiaries CERFACS and CLS, and occasionally by
external computer services and engineering companies. The group is developing
several operational systems at a time. Only one system is used within the
Mersea strand1 context and is described below.
Mercator has been providing weekly analysis and real-time nowcast (T0), and
forecast (T0+7 days and T0 +14 days) bulletins of the three-dimensional ocean
in the North and tropical Atlantic up to 20 degrees S since January 17th 2001.
The medium-resolution bulletin (1/3 degree; one point computed every 35 km at
the equator) gives conditions from the surface right down to the bottom. This
resolution is suitable for monitoring ocean circulation on a large scale. The
first high-resolution bulletin (1/15 degree; one point computed every 5 to 7 km
throughout the region of interest) was published on January 8th 2003 and is
eddy-resolving. It covered the North Atlantic between 9 degrees N and 70
degrees N and the whole of the Mediterranean Sea. A low resolution global ocean
model (2 degrees; one point computed every 220 km at the equator) with
altimetry data assimilation is also available since May 2004. A high
resolution global operational circulation model (1/4 degrees) assimilating
satellite and in situ data is planned for the 2005 year. For more information
see Mercator Configurations Summary at
Additional information about the Model:
The four ocean model configurations retained by the Mercator project are all
based on the OPA z-coordinates ocean circulation model (Madec et al., 1998).
OPA is an incompressible Navier-Stokes primitive-equation model using
Boussinesq rigid-lid approximation that describes the temporal evolution of
velocity, temperature and salinity in three dimensions. Mixed layer dynamic is
ruled by TKE turbulent closure equations (1.5 closure scheme) (Blanke et al.
1993). The first model configuration is the "Maquette Atlantique Nord" (MNATL)
between 20 degrees S and 70 degrees N. The second one is the "Prototype
Atlantique Mediterranee" (PAM) between 9 degrees N and 70 degrees N. The
horizontal resolution is 1/3 degree for MNATL, 1/15 degrees for PAM and 43
levels are used on the vertical for both of them. The bathymetry is processed
from the Smith and Sandwell (1997) data base and ETOPO5. Momentum and heat
forcings are daily ECMWF forcing. Surface temperature is restored from Reynolds
analyses (Reynolds & Smith, 1994), which include satellite and in-situ
observations. Surface salinity is restored from climatology. The model is
initialized using Reynaud (Reynaud et al. 1998) seasonal climatology. At last,
two Ocean Global Prototypes, POG (1/4 degrees, 43 levels) and ORCA (2 degrees,
31 levels) are being implemented.
The data assimilation method (SAM; Systeme d'Assimilation Mercator) used is the
reduced-order optimal interpolation (OI) scheme SOFA (Sub Optimal Filtering of
Altimetry) (De Mey and Benkiran, 2002) coupled with the PALM software coupler
(PALM group, 2000). The baroclinic component is corrected applying a
lifting-lowering method similar to Cooper and Haines method (1996). Data
assimilation is stopped along isobaths 500m towards the coast. Sea level
anomaly (SLA) from Jason1/ERS2-Envisat/GFO is assimilated along track, once a
week. The mean sea surface height (MSSH) used during the assimilation process
is the one from Rio et al. (2003) diagnosed from in-situ observations in the
Atlantic ocean. In the Mediterranean basin, MSSH is made out of several
numerical simulations. Version 1 products assimilates altimetry data (SLA)
only, while version 2 products assimilates altimetry and in situ data (SLA,
Sea Surface Temperature (SST), Sea Surface Salinity (SSS) and In situ
Mercator bulletins contain a range of parameters selected to depict ocean
conditions and dynamics. These include: salinity, temperature, surface
currents, zonal, meridian and vertical velocities, transport, sea surface
height, mixed layer depth, barotropic height, baroclinic height. "Model:
analysis and forecasting" 3D ocean products and "observed ocean" 3D products
can be accessed on-line through Mercator Web Products (full domain and zonal
animations, whole maps, zonal maps, sections and moorings graphs). The
"observed ocean" system is based on altimetry and in situ data measurements.
For additional product information see
Mercator web products are designed for a wide audience (freely available),
while numerical products are files for professional users and are available on
a remote server. Please make an e-mail request to email@example.com
Archive bulletins are also available to identify longer-term patterns.
Mercator web products can be browsed on MERCATOR product web site:
Web products include the 3D modelled ocean (nowcasts and forecasts) Mercator
prototypes (Medium-resolution Atlantic (PSY1V2, 1/3 degrees), High-resolution
North Atlantic and Mediterranean (PSY2V1, 1/15 degrees), Global low-resolution
(Minipog/PSY2G1;2 degrees)) and 3D global observed ocean products from
satellite observation data (altimetry, surface sea temperatures) and in situ
data, data intercomparison and 3D reconstitution of oceanic fields.
In the Mersea strand1 european project context, Mercator makes available via an
DODS/Opendap server its PSY2 high-resolution prototype products since
01/06/2003. Mercator also offers access to its products via the LAS implemented
in the Mersea context. For more information see
Latitude Resolution: regional (1/3, 1/15 degrees), global (2 degrees)
Longitude Resolution: regional (1/3, 1/15 degrees), global (2 degrees)
Vertical Resolution: regional (43 vertical levels), global (31 vertical levels)
Temporal Resolution: daily, weekly
OCEANS > OCEAN CIRCULATION > DIFFUSION
OCEANS > OCEAN CIRCULATION > OCEAN CURRENTS
OCEANS > OCEAN CIRCULATION > OCEAN MIXED LAYER
OCEANS > OCEAN HEAT BUDGET > HEAT FLUX
OCEANS > OCEAN TEMPERATURE > OCEAN MIXED LAYER
OCEANS > OCEAN TEMPERATURE > SEA SURFACE TEMPERATURE
OCEANS > OCEAN TEMPERATURE > THERMOCLINE
OCEANS > OCEAN TEMPERATURE > WATER TEMPERATURE
OCEANS > OCEAN WINDS > WIND STRESS
OCEANS > SALINITY/DENSITY > HALOCLINE
OCEANS > SALINITY/DENSITY > PYCNOCLINE
OCEANS > SALINITY/DENSITY > SALINITY
OCEANS > SEA SURFACE TOPOGRAPHY > SEA SURFACE HEIGHT
Access Constraints Mercator web real time image products (GIF format) are designed for a wide
audience (freely available, except zonal maps younger than 30 days need
authorized access), while numerical products are files for professional users
and are available on a remote server with authorized access.
Please, you must justify your request to these products. E-mail request to
firstname.lastname@example.org or download the form
Data Set Progress
Distribution Media: LAS, DODS/Opendap Access (restricted access), Image Browse (public access)
Distribution Format: GIF, NetCDF, CF/COARDS
Publications related to Mercator project in specialized reviews
Davidson, F., Hernandez, F. and Rio, M.H. : Impact of a realistic Mean Dynamic
Topography on the forecast capabilities of the Mercator operational model
assimilation system of the North ... Atlantic. In prep.
Drillet, Y., Bourdalle-Badie, R., Siefridt, L., Le Provost, C., The
MEDDIES in the Mercator North Atlantic and Mediterranean Sea eddy resolving
model. Accepted in the Journal of Geophysical Research.
Guinehut, S., Larnicol, G., Le Traon, P.Y., 2002, Design of an array of
profiling floats in the North Atlantic from model simulations. Journal of
Marine Systems, 35, 1-9.
Guinehut, S., Le Traon, P.Y., Larnicol, G., Philipps, S., 2004, Combining Argo
and remote-sensing data to estimate the ocean three-dimensional temperature
fields - A first approach based on simulated observations. Journal of Marine
Systems, 46 (1-4), 85-98.
Lagarde, T., Piacentini, A. and Thual O., 2001 : A new representation of
data-assimilation methods: The PALM flow-charting approach. Q. J. R. Meteorol.
Soc., 127, 571, 189-207.
Publications in the books
De Mey, P., M. Benkiran, 2002, A multivariate reduced-order optimal
interpolation method and its application to the Mediterranean basin-scale
circulation. In : Ocean Forecasting, Conceptual basis and applications, N.
Pinardi and J.D. Woods, Eds., Springer-Verlag, Berlin Heidelberg New York,
International congress proceedings
Bahurel,P. and Toumazou, V., Mercator ocean monitoring and forecasting: a 4D
vision of the global ocean. Committee on Space Research - COSPAR 2004 Final
meeting, Paris, France, Jully 2004.
Bahurel, P., De Mey, P., Le Provost, C. and Le Traon, P.Y., 2002 : A GODAE
prototype system with applications - Example of the Mercator system. "En route
to GODAE" 2002 Proceedings, 137-142, Edited by CNES, France.
Bahurel, P. and the Mercator Project Team, 1999 : Mercator, developing an
integrated system for operational oceanography. OceanObs99 Proceedings, Saint
Bahurel, P, Dombrowsky, E.,Lellouche J.-M., and the Mercator project team,
Mercator Ocean Monitoring and Forecasting System, near-real time assimilation
of satellite and in situ data in different operational ocean models. 36th
International Liege Colloquium on Ocean Dynamics, Liege, Belgium, April 2004
Benkiran, M., Greiner, E., Dombrowsky, E., Mercator Data Assimilation Systems:
From a Simple Altimeter Data Reduced Order Optimal Interpolation to a Fully
Multivariate Multi-data Assimilation System, EGU (European Geosciences Union),
Nice, France, April 2004.
Crosnier, L., Le Provost, C. and the MERSEA Team, An ocean forecast systems
intercomparison within the Mersea project : methodology and results, EGU
(European Geosciences Union), Nice, France, April 2004.
Derval, C., Durand, E., Fleury, L., Garric, G. and Remy, E., The Mercator
global ocean model, EGU (European Geosciences Union), Nice, France, April 2004.
Drillet, Y.,Bourdalle-Badie, R., Daget, N., Last decade simulation with the
Mercator North Atlantic prototype, EGU (European Geosciences Union), Nice,
France, April 2004.
Ferry, N., Remy, E. , Brasseur, P., de Mey, P.,The Mercator global ocean
operational forecasting systems: first evaluation. 36th International Liege
Colloquium on Ocean Dynamics, Liege, Belgium, April 2004
Garric, G., Derval, C., Durand, E., Fleury, L., Le Provost, C., and Remy, E., A
preliminary study of the ECMWF analysis at high-latitudes with a coupled
ocean-sea ice model. EGU (European Geosciences Union), Nice, France, April
Garric, G. et Hodges, K.I., Impacts of sea ice on the Southern Hemisphere storm
tracks distribution with a simple GCM. EGU (European Geosciences Union), Nice,
France, April 2004.
Guinehut, S., Larnicol, G., Le Traon, P.Y., Combining satellite and in-situ T/S
profile data to better estimate the 3D thermohaline fields. 36th International
Liege Colloquium on Ocean Dynamics, Liege, Belgium, April 2004
Guinehut, S., Le Traon, P.Y. et Larnicol, G., Comparing and combining argo data
with altimeter data, EGU (European Geosciences Union), Nice, France, Avril
Etienne, H. and Benkiran, M., Forecast error study for the Mercator
assimilation system: Estimation of the Fully Multivariate Multi-data
Assimilation parameters., EGU (European Geosciences Union), Nice, France, April
Lellouche J.M., Greiner E., Drillet Y., Bourdalle-Badie R., Near-real-time
Assimilation of Satellite Data in North Atlantic and Mediterranean High
Resolution Model, EGU (European Geosciences Union), Nice, France, April 2004.
Le Provost,C., Bahurel, P. , Bell, M., Bertino, L., Blanc, F., Chassignet, E.,
Coppini, G., Crosnier, L., Dombrowsky, E. , Fratianni, C., Hurlurt, H., Le
traon, P.Y. , Lisaeter, K., Liu, C.L., Pinardi, N., Godae Atlantic and
Mediterranean Sea Prototype Project. 36th International Liege Colloquium
on Ocean Dynamics, Liege, Belgium, April 2004
Testut, C.E., Tranchant, B., Brasseur, P., De Mey, P., Recent developments of
the Mercator assimilation system (sam): towards the SEEK filter
Tranchant B., Testut C-E. , Brasseur P. and De Mey P., Recent Developments of
the Mercator Assimilation System (SAM): Towards the Seek Filter, The 2004 Joint
Assembly (CGU, AGU, SEG, EEGS), Montreal, Canada.
Toumazou, V. and the Mercator Ocean team, Data sets from the Mercator Ocean
monitoring and forecasting system.
Creation and Review Dates
DIF Creation Date: 2004-12-27
Last DIF Revision Date: 2009-04-15