This is the slide version of the poster with the same title I presented at the European Geosciences Union in Vienna last month (EGU'07) under the Operational Oceanography session

1. Assessing the quality of a pre-operational model for the
Portuguese coast
Riflet G.1, P.C. Leitão2, A.R. Trancoso3, A. Canas1, R. Fernandes1, L. Fernandes1, A.C.
Garcia1, R.J. Neves1
1 – MARETEC, DEMecanica, Instituto Superior Técnico, 1049-001 Lisbon,
Portugal (guillaume.maretec@ist.utl.pt)
2 – HIDROMOD, Av Manuel da Maia 36 3-e, 1000-201 Lisbon, Portugal
(hidromod@hidromod.com)
3 – METEO-IST, Secção Energia e Ambiente, DEMecanica, Instituto Superior
Técnico, 1049-001 Lisbon, Portugal (ana.rosa.maretec@ist.utl.pt)
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 1

2. Introduction
• Does the downscaling of large-scale oceanic forecasting solutions allow a reliable way
for forcing operational regional and local models? Does it improves the local solutions
results? If so, how can we quantify it? These are the fundamental questions that this work tries
to tackle partially.
• A pre-operational system was implemented at MARETEC that performs weekly
hydrodynamic forecasts of the Portuguese coast and of the Estremadura region. It
downscales the Mercator-Océan PSY2V2R1 1/15º solution to a 0.06º and 0.02º domains
using the MOHID water modeling system. Tide forced from the FES2004 tidal atlases was
added, and atmospheric forcing from a regional scale forecasting system was provided by
Meteo-IST for surface forcing. Also, a freshwater discharge was estimated based on a 2006
flow time series from Instituto da Água for simulating the Tagus estuary input.
•The results are analyzed against published evidences, and against tidal station data and SST
remote sensing imagery.
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 2

3. Models Setup
•Three domains are modeled: a 2D barotropic model of the west
Iberia region bounded by [13.7 5.3] ºW x [33.5 46.1] ºN; a 3D
baroclinic model of the west Iberia region, nested to the latter,
bounded by [12.6 5.5] ºW ; and a 3D baroclinic model of the
Estremadura region bounded by [11.2 8.8] ºW x [40.3 37.5] ºN
and nested to the latter.
•Each domain radiates the water level using a Flather radiation
scheme, except for the 2D barotropic model that radiates the level
using a Blumberg radiation scheme.
•The 3D models initial S and T are directly interpolated from the
Mercator-Océan solution.
•Atmospheric forcing is imposed with latent and sensible heat
fluxes, solar radiation, infrared radiation, atmospheric pressure,
evaporation and precipitation coming from the MM5 results from the
Meteo-IST model.
•The 2D barotropic model has the level forced at the open
boundaries by the FES2004 tidal atlas solution. The nested models On the left panel, the Western Iberia coast
baroclinic model bathymetry. Bounded by [12.6
are forced at the open boundaries with S, T, u, v and η from the father
5.5] ºW x [34.4 45.0] ºN. 0.06º spatial resolution,
model and/or the Mercator-Océan solution.
labeled P. On the right panel, Portugal continental
•A sponge layer is applied near the open boundaries where a Flow central regional coastal model bathymetry.
Relaxation Scheme is employed and a higher horizontal turbulent Bounded by [11.2 8.8] ºW x [40.3 37.5] ºN. 0.02º
viscosity is applied. spatial resolution, labeled C. Baseline data from
ETOPO 2’.
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 3

4. Results
The application is run weekly and provides 5 day forecast for
the three-dimensional hydrodynamic circulation off the coast
of Portugal. Results since November 2006 are available at
http://data.mohid.com served by an Opendap server and a
Live Access Server (LAS).
The results shown are either instantaneous values, either a
statistical average performed over the available set of weekly
runs.
Instantaneous results seem to evidence that the finer-scale
model is more prone to generate internal waves.
To the left, the interpolated temperature fields of the Mercator
solution. To the right, the super-position of the temperature fields
of the C model over the P model. The temperature scale's interval
is [14.5 20.0] ºC at the surface (top) and [12.0 14.7] ºC at 250 m
(bottom). The graphical tool is Mohid GIS.
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 4

5. Results
The Mediterranean Waters (MW) spreading pathway are
evidenced in currents at intermediate depth and with the
salinity distribution at 1000 m. The models averaged results
seem realistic when compared with observations reported in
the literature.
Color map and contours of salinity
distribution ensemble average at 1000
m depth ranging in
interval [35.6 36.2] showing the
spreading pathway of the MO off
western Iberia. Contour lines are
valued
[35.6; 35.78; 35.84; 35.9; 35.96;
36.02; 36.08; 36.14; 36.2]
Horizontal distribution of velocity
ensemble average at 2 m depth for the
top panel and 645 m
depth for the bottom panel. Tw o main
branches of the MW spreading
pathw ays are w ell pronounced in
the bottom panel. the polew ard slope
current branch, and the cyclonic
recirculation f low ing southw ard.
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 5

6. Results
The Mediterranean outflow (MO) in the model shifts from a
bottom current to a buoyancy driven intermediate depth jet
current in the Gulf of Cadiz at about 8 ºW. This is a known
realistic scenario.
On the left, ensemble averages of meridional velocity
contours of 0.1 ms-1 apart and color maps in the interval [-.1
.1] ms-1 are shown. Positive velocities are equatorward and
negative velocities are poleward. On the right, ensemble
On the left panel, salinity contours of [35.5; 35.52; 35.83; 35.94; 36.05; averages of salinity contours of
36.16; 36.27; 36.38; 36.49; 36.6] and color maps in the interval [35.5 36.6].
[35.6; 35.66; 35.72; 35.78; 35.84; 35.90; 35.96; 36.02;
On the right panel, ensemble averages of zonal velocity contours of [-.15;
36.08; 36.14; 36.2] and color maps in the interval [35.6 36.2]
-.12; -.09; -.06; -.03; 0; .03; .06; .09;.12; .15] ms -1 and color maps in the
are shown. The plots are zonal sections of the Portuguese
interval [-.15 .15] ms -1. The plots are meridional sections in the Gulf of
coast at 40.95 ºN for the top panels; and 38.25ºN for the
Cadiz at longitude 7.83 ºW. The MO shifts from a bottom current to a
bottom panels. The cross sections are shown in the
buoyancy driven intermediate depth jet current. The cross sections are
bathymetries figure.
shown in the bathymetries figure.
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 6

7. Results
Quality assessment can be performed with instantaneous results 4.5
4
agains tidal stations and remote-sensing SST imagery. 3.5
3
2.5
Water level (m)
2
1.5
1
0.5
0
09-02- 11-02- 13-02- 15-02- 17-02- 19-02- 21-02- 23-02- 25-02-
2007 2007 2007 2007 2007 2007 2007 2007 2007
12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00 12:00
Time
Sines tide gauge Operational model
Water level from from a tidal station in pink
located at 37º57’ ºN and 8º55’ ºW in Sines and
illustrated in the the bathymetries figure. Water
level from the pre-operational model in forecast
mode for the same location. The correlation is
0.99 + 5e-3 and the RMSE is 0.19 + 5e-3 m.
The Mercator solution sea surface temperature daily average on the September 9th 2006, at the left. A NOAA
sea surface temperature satellite image taken during the same day, at the middle. At the right, the Mohid
instantaneous solution taken the same day at 19h00 hours. The temperature scale is set to [17ºC 22ºC]. Note
that the color palettes diverge between the satellite images and the model's fields. The graphical tool used is
Mohid GIS.
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 7

8. Conclusions Future work
• Perform calculus continuation instead of
•The MW main spreading pathways seem
weekly spin-up;
realistic when compared with observations. Two
• Calculate mass fluxes in predefined cross-
expected main branches are reproduced by our
sections;
model.
• Calculate TKE;
•The salinity spreading pattern at 1000 m depth
• Acquire SST from remote-sensing data
in our model is typical of other models findings.
(MODIS, MERIS);
•The regional model with finer resolution seems
• Gather available CTD, ADCP and RAFOS
to be internal-wave permitting.
data in order to compare with the models
•The tidal forcing with FES2004 provides an
results;
added value to the Mercator-Océan solution. • Perform further analysis of the models
•Comparison with SST imagery seems results against in-situ tidal stations data,
promising in order to assess the quality of the • Implement the data plotting of the results
operational model. operationally;
• Eventually, implement a digital filter for the
calculation of stable non-trivial initial
conditions.
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 8

9. References
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252, 2005.
• Martins, F., R. Neves, P.C. Leitão, and A. Silva, 3D modeling in the Sado estuary using a new generic coordinate approach, oceanologica Acta,
24, S51-S62, 2001.
• Flather, R.A., A tidal model of the northwest European continental shelf, Mem. Soc. R. Sci. Liege, 6 (10), 141-164, 1976.
• Blumberg, A.F. and L.H. Kantha, 1985. Open boundary condition for circulation models. J. of Hydraulic Engineering, ASCE, 111, 237-2555.
• Martinsen, E.A., and H. Engedahl., Implementation and testing of a lateral boundary scheme as an open boundary condition in a barotropic
ocean model, Coastal Engineering, 11, 603-627, 1987.
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shelf-slope region. Journal of Marine Systems, 26 53–74,
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• Coelho H. S., R. J. J. Neves, M. White, P. C. Leitão, and A. J. Santos. A model for ocean circulation on the iberian coast. Journal of Marine
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Acknowledgements
The authors w ish to thank Mercator-Océan for providing the ocean forecasts and reanalysis (http.//w w w .mercator-ocean.fr/),
Meteo-IST (in particular J. J. Delgado Domingos) for providing the atmospheric forecasts (http.//meteo.ist.utl.pt/),
Hidromod, for providing logistical support and in-situ data (http.//w w w .hidromod.pt/).
This w ork is funded by the EU in the framew ork of FP6 GMES activities according the terms of the contract SST4-CT-2005-012336 (INSEA project).
This w ork is funded by the EU in the framew ork of INTERREG III-B Espaço-Atlântico activities (EROCIPS and 207-EASY projects).
G. Riflet, A.R. Trancoso and A. Canas acknow ledge grants SFRH/BD/17631/2004, SFRH/BD/17957/2004 and SFRH/BD/14185/2003, respectively, from Fundação para a Ciência e
Tecnologia.
April 16th 2007 G. Riflet, EGU symposium Vienna 2007 9