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The effect of stratification on tidal current profiles in a region of fresh-water influence

Publication Type :
Publication
Publication date :
1994
Language :
English
Author(s) :
Visser Aw, Souza Aj, Hessner K, Simpson Jh
Affiliation(s) :
UNIV COLL N WALES,SCH MARINE SCI,MENAI BRIDGE LL59 5EY,GWYNEDD,WALES
UNIV HAMBURG,INST MEERESKUNDE,D-22529 HAMBURG,GERMANY
Source :
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1994 , Vol. 17 , N. 4 , P. 369-381
WOS© Times Cited :
51
Abstract :
Observations of the semi-diurnal tidal current ellipses within the Rhine ROFI are reported. The vertical structure of these tidal ellipses are observed to be significantly different for stratified and well mixed conditions. in particular, during well mixed conditions, tidal currents are essentially rectilinear and directed parallel to the coast. With the onset of stratification, significant cross-shore components, reaching 40% of the magnitude of the along-shore components appear. These components are 180 degrees out of phase from near surface to near-bottom with surface currents rotating anticyclonically, and bottom currents cyclonically. It is proposed that this phenomenon may be explained by a decoupling of the upper and lower portions of the water column during stratified periods due to reduced viscosity within the pycnocline. A two layer model is used to examine this hypothesis and appears to be successful in reproducing many of the features of the observed semi-diurnal tidal ellipse variability.
How to cite this document:

Visser Aw, Souza Aj, Hessner K, Simpson Jh (1994). The effect of stratification on tidal current profiles in a region of fresh-water influence. Oceanologica Acta, 17(4), 369-381. Open Access version : http://archimer.ifremer.fr/doc/00098/20898/