Numerical model
The model based on the primitive equations provides a forecast computation of currents, sea surface elevation, salinity and density ftelds. It solves
theses equations with finite difference schemes using sigma coordinates
and the time splitting method. The turbulence closure model is based on
a simplified k-epsilon assumption (Luvten et al., 1996).
The model area extended from the Spanish coast to 49°N latitude and
from 8°W to the French coast in longitude (fig. 1). Grid step size was
five kilometres. The thirty sigma levels were distributed in such a way
that the mixed surface layer is alwavs described with at least fivc points,
even at depths greater than 4000 metres.
Along open boundaries, the 3D model was protided with sea surface elevation by a wider 2D barotropic model forced with constant weather
conditions (wind and pressure). Tidal components along the open
boundaries of that model are extracted from “Schwiderski Atlas”.
Observations
Thc Adour estuary is fed by many small rivers (i.e., the Adour, gave de
Pau, gave d’Oloron and Luy) which have their sources in the Pyrenees.
The annual mean flow of freshwater in the mouth of the estuaty' is
about 300 cubic metres per second. Tlae peak flow, which happens during winter or spring, may excecd 1000 m
3 /s during few days.
The French oceanographic and hydrographic service (Shom) has conducted hydrological measurements at sea over different seasons since
1997. One of these surveys, Modycot 98-3, which took place during
April 1998, clearly shows the extension of the plume northward as far as
44°N and probably, mixed with the Gironde plume, as far as 45°N
(fig. 1). The plume is driven along the coast while mixing with marine
water resulting in slightly freshwater (2 psu less).
Simulation of the year 1995
The true behaviour of the Adour plume is complex because of interactions
between various processes and the significant variabilitv of river discharges
and winds.
This application aimed to pertorm a full year’s simulation in order to describe the hwlrology ewilution on the Atlantic continental shelf. Thus, in the
future, this case should provide a basis for simulations over several years
and make it possible to compare them with existing measurements (surveys,
remote sensing).
50
The model based on the primitive equations provides a forecast computation of currents, sea surface elevation, salinity and density ftelds. It solves
theses equations with finite difference schemes using sigma coordinates
and the time splitting method. The turbulence closure model is based on
a simplified k-epsilon assumption (Luvten et al., 1996).
The model area extended from the Spanish coast to 49°N latitude and
from 8°W to the French coast in longitude (fig. 1). Grid step size was
five kilometres. The thirty sigma levels were distributed in such a way
that the mixed surface layer is alwavs described with at least fivc points,
even at depths greater than 4000 metres.
Along open boundaries, the 3D model was protided with sea surface elevation by a wider 2D barotropic model forced with constant weather
conditions (wind and pressure). Tidal components along the open
boundaries of that model are extracted from “Schwiderski Atlas”.
Observations
Thc Adour estuary is fed by many small rivers (i.e., the Adour, gave de
Pau, gave d’Oloron and Luy) which have their sources in the Pyrenees.
The annual mean flow of freshwater in the mouth of the estuaty' is
about 300 cubic metres per second. Tlae peak flow, which happens during winter or spring, may excecd 1000 m
3 /s during few days.
The French oceanographic and hydrographic service (Shom) has conducted hydrological measurements at sea over different seasons since
1997. One of these surveys, Modycot 98-3, which took place during
April 1998, clearly shows the extension of the plume northward as far as
44°N and probably, mixed with the Gironde plume, as far as 45°N
(fig. 1). The plume is driven along the coast while mixing with marine
water resulting in slightly freshwater (2 psu less).
Simulation of the year 1995
The true behaviour of the Adour plume is complex because of interactions
between various processes and the significant variabilitv of river discharges
and winds.
This application aimed to pertorm a full year’s simulation in order to describe the hwlrology ewilution on the Atlantic continental shelf. Thus, in the
future, this case should provide a basis for simulations over several years
and make it possible to compare them with existing measurements (surveys,
remote sensing).
50