Evolution of the circulation pattern in the Ría
of La Coruna (NW Spain): residence time
in the harbor area
.
(1,2)
1,2)
Moncho Gomez Gesteira , Maite De Castro ,
Juan [oséTaboada , Ricardo Prego'
1 ^ Pedro Montero'
11 ,
Flavio Martins ’ Vicente Pérez Villar '
(1) Universidad de Santiago de Compostela, Facultad de Fîsica, Grupo de Fisica no lineal,
15706 Santiago, Espana
(2) Universidad de Vigo, Dpto Fîsica Aplicada, Campus de Ourense, Espana
(3) Instituto de Investigaciones Marinas (CSIC), Eduardo Cabello 6, 36208 Vigo, Espana
(4) Instituto Superior Técnico, Av. Rovisco Pais, 1096 Lisboa Codex, Portugal
moncho@fmmeteo.usc.es
Abstract
A comparison between pristine and present disturbed conditions has
been carried out in the Ria of La Coruña by means of a 3D baroclinic
model. In this century, the shoreline and the circulation pattern of this
area have been altered by the building of a harbctur, a breakwater and a
dam that controls the discharge of the main river (Mero) flowing into
the estuanp In particular, the residence time in the harbour area has increased by mttre than 35% during the last centurv.
Introducciôn
The Galician coast, located in the NW part of the Iberian Peninsula, is
vert' irregular, with a great number of coastal embavments, called rias.
These rias can bc divided in the so-called Rias Baixas, south of Cape Finisterre, and the Rias Altas in the northem part. The hydrodynamics of the
Rias Baixas is mainly driven by tides, while the long-term circulation has
been established to follow a two-layered residual pattern (Fraga & Margalef, 1979), with surface water leaving the ria and bottom water entering it.
In the last years, the hydrodynamics of these rias has also been studied
by means of numerical models (Gômez-Gesteira et al., 1999; Taboada et
tii, 1998; Montero et al., 1999). Thc results obtained by these authors
have confirmed the existence of a two-layered residual pattem underlying the tidal circulation. The Rias Mtas of Galicia have received
considerably less attention. One of these rias is the Ría of La Coruna,
whose hydrography has been qualitatively described bv Cabanas et al.
(1987). They found a two-layered circulatictn related to the partially
mixed estuarine nature of this ria. A 2D numerical model has been applied to this ria in order to studt’ the currents drtven by tides (Montero
et ai, 1997). This work showed two eddies appearing in the central part
of the ria, when the average over a period much longer than the tide period is considered. These eddies can be induced by the presence of a
256
of La Coruna (NW Spain): residence time
in the harbor area
.
(1,2)
1,2)
Moncho Gomez Gesteira , Maite De Castro ,
Juan [oséTaboada , Ricardo Prego'
1 ^ Pedro Montero'
11 ,
Flavio Martins ’ Vicente Pérez Villar '
(1) Universidad de Santiago de Compostela, Facultad de Fîsica, Grupo de Fisica no lineal,
15706 Santiago, Espana
(2) Universidad de Vigo, Dpto Fîsica Aplicada, Campus de Ourense, Espana
(3) Instituto de Investigaciones Marinas (CSIC), Eduardo Cabello 6, 36208 Vigo, Espana
(4) Instituto Superior Técnico, Av. Rovisco Pais, 1096 Lisboa Codex, Portugal
moncho@fmmeteo.usc.es
Abstract
A comparison between pristine and present disturbed conditions has
been carried out in the Ria of La Coruña by means of a 3D baroclinic
model. In this century, the shoreline and the circulation pattern of this
area have been altered by the building of a harbctur, a breakwater and a
dam that controls the discharge of the main river (Mero) flowing into
the estuanp In particular, the residence time in the harbour area has increased by mttre than 35% during the last centurv.
Introducciôn
The Galician coast, located in the NW part of the Iberian Peninsula, is
vert' irregular, with a great number of coastal embavments, called rias.
These rias can bc divided in the so-called Rias Baixas, south of Cape Finisterre, and the Rias Altas in the northem part. The hydrodynamics of the
Rias Baixas is mainly driven by tides, while the long-term circulation has
been established to follow a two-layered residual pattern (Fraga & Margalef, 1979), with surface water leaving the ria and bottom water entering it.
In the last years, the hydrodynamics of these rias has also been studied
by means of numerical models (Gômez-Gesteira et al., 1999; Taboada et
tii, 1998; Montero et al., 1999). Thc results obtained by these authors
have confirmed the existence of a two-layered residual pattem underlying the tidal circulation. The Rias Mtas of Galicia have received
considerably less attention. One of these rias is the Ría of La Coruna,
whose hydrography has been qualitatively described bv Cabanas et al.
(1987). They found a two-layered circulatictn related to the partially
mixed estuarine nature of this ria. A 2D numerical model has been applied to this ria in order to studt’ the currents drtven by tides (Montero
et ai, 1997). This work showed two eddies appearing in the central part
of the ria, when the average over a period much longer than the tide period is considered. These eddies can be induced by the presence of a
256