TY - JOUR
T1 - A three-dimensional model of tidal currents in the mouth of the Tagus estuary
AU - Fortunato, André B.
AU - Baptista, António M.
AU - Luettich, Richard A.
PY - 1997/12
Y1 - 1997/12
N2 - Three-dimensional simulations of barotropic fides are used to investigate the complex circulation at the mouth of the Tagus estuary. Comparison with field data shows that elevations are well represented in the main area of interest, but velocities are slightly over-predicted due to a simplified treatment of intertidal flats. Model results show the existence of strong velocity phase lags (up to 1.75 hours for the semi-diurnal constituents) between the shallow areas and the deep channel. These phase lags are partially responsible for the generation by advective accelerations of a strong residual velocity field (velocities reach 0.5 m s-1) with well defined eddies. The interaction between the residual and tidal velocity fields in turn generates strong chaotic stirring. Localized sigma coordinates (LSC), a recently proposed method which allows the number of nodes per vertical to vary horizontally, are used for the first time in a three-dimensional application. A previously proposed criterion for the horizontal distribution of the total number of vertical nodes is shown to be inadequate when advective accelerations are important. However, with an alternative criterion, the use of LSC reduces maximum errors by a factor of two relative to traditional sigma coordinates.
AB - Three-dimensional simulations of barotropic fides are used to investigate the complex circulation at the mouth of the Tagus estuary. Comparison with field data shows that elevations are well represented in the main area of interest, but velocities are slightly over-predicted due to a simplified treatment of intertidal flats. Model results show the existence of strong velocity phase lags (up to 1.75 hours for the semi-diurnal constituents) between the shallow areas and the deep channel. These phase lags are partially responsible for the generation by advective accelerations of a strong residual velocity field (velocities reach 0.5 m s-1) with well defined eddies. The interaction between the residual and tidal velocity fields in turn generates strong chaotic stirring. Localized sigma coordinates (LSC), a recently proposed method which allows the number of nodes per vertical to vary horizontally, are used for the first time in a three-dimensional application. A previously proposed criterion for the horizontal distribution of the total number of vertical nodes is shown to be inadequate when advective accelerations are important. However, with an alternative criterion, the use of LSC reduces maximum errors by a factor of two relative to traditional sigma coordinates.
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U2 - 10.1016/S0278-4343(97)00047-2
DO - 10.1016/S0278-4343(97)00047-2
M3 - Article
AN - SCOPUS:0344431238
SN - 0278-4343
VL - 17
SP - 1689
EP - 1714
JO - Continental Shelf Research
JF - Continental Shelf Research
IS - 14
ER -