ayoub nadia

Coastal Ocean Continuum in surface Topography Observations (COCTO)
PIs: Nadia Ayoub and Pierre De Mey, LEGOS, Toulouse, France
Project participants
Methodology
PIs: Nadia Ayoub & Pierre De Mey (LEGOS)
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Co-Is:
Guillaume Charria (IFREMER/LOPS, Brest)
Marine Herrmann (IRD/LEGOS, Hanoi)
Florent Lyard (CNRS/LEGOS)
Patrick Marsaleix (CNRS/LA)
Other participants:
Sylvain Ouillon (IRD/LEGOS)
Florence Toublanc (LEGOS post-doc)
Damien Allain (LEGOS engineer)
Thomas Duhaut (LA engineer)
Ozge Yelecki (LOPS PhD student)
Sébatien Theetten (LOPS engineer)
Frédéric Vandermeirsch (IFREMER/LOPS)
Two target coastal regions
Interested? Contacts:
2D and 3D fine-scale numerical modelling
Ensemble stochastic modelling
Satellite and in situ data, SWOT ocean simulator
Data assimilation by Ensemble Kalman filtering
Pierre De Mey [email protected]
Nadia Ayoub [email protected]
Topic 2: Estuary to shelf transition
Identification of coastal structures linked to plumecirculation interactions (SYMPHONIE circulation model)
Calculation of the associated geostrophic currents
Bay of Biscay
Evaluation of the observability of
these structures with the SWOTocean simulator (Gautier and
Ubelmann, 2015)
30 km
5 cm
Daily mean sea surface elevation (m)
August 2012
Science
Science drivers:
• The estuary-shelf-coastal ocean continuum,
and in particular its small scales
• Cross-shelf exchanges
• Fine-scale dynamics on the shelf under the
influence of rivers, tides, the atmosphere and
larger-scale dynamics
• Signature of fine-scale processes in seasurface height
• Potential impact of SWOT measurements via
data Assimilation, along with other data
Project structure:
• Topic 1. Lower estuary dynamics :
• accuracy and realism assessment of 3D modelling
of river flow, barotropic tides, storm surges and
surface waves in lower estuaries
• 2D vs. 3D surface signature (sea level) of estuarine
dynamical processes
• impact of extreme events (flooding, storms)
• salinity and influence of mixing (plus possibly mud
flow effects) on the stratification
• Hydrological modelling and T-UGOm comparisons
to be made in collaboration with B. Laignel and L.
Chevalier (Univ. of Rouen) within their own SWOT
project.
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Topic 2. Estuary to shelf transition
Topic 3. Small-scale processes on the shelf
Topic 4. Shelf break processes
Topic 5. Multiscale estimation approaches
The Gulf of Tonkin case study
Possible applications in the Red River delta and CZ
2 SYMPHONIE grids currently used : one for the South
China Sea (SCS), one for the Gulf of Tonkin (GoT)
Results from the SWOT simulator (m)
Daily mean sea surface salinity (psu)
Geostrophic currents calculated
from the ssh gradient (m/s)
Bathymetry
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1000
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Goals: fluxes and fate of dissolved and particulate matter
at the continent-ocean interface for the benefit of
science (chemical cycles), health (contamination),
management (sustainable development).
F. Toublanc et al., 2016
Water Quality
• Fate of dissolved and particulate matter during floods
• Contamination in case of accidental chemical release
Topic 3: Small-scale processes on the shelf
• What will SWOT data
bring to the
description and
understanding of the
mid-shelf seasonal
fronts in Sea Surface
Height ?
• Intensity of mesoscale
activity over the shelf
(including the outer
part) ?
• Other active
processes with a
potential signature on
SSH (as internal waves
for example) ?
Singularity exponents
(28/03/2012 MODIS – Chl. conc.)
SCS grid, resolution
1 to 6 km
GoT grid, resolution
0.5 to 5 km
We intend to use the fast-sampling phase to
evaluate the realism of the model and the
observability of small scale structures in the GoT
and SCS in SWOT data.
Lagrangian studies
• Sedimentation
in the Ha Long bay
• Release of particles by
the Red River and from
the northern basin with
cement factories
& mining activities
Extreme events
• Storm surges, setup,
coastal erosion.
Illustration of small-scale patterns in the Bay of Biscay
Yelecki et al., LOPS, 2016
M. Herrmann and S. Ouillon, 2016