Non-linear interaction between tidal and subinertial barotropic flows in the Strait of Gibraltar

• Published in: Oceanologica acta 1998-01, Vol.21 (1), p.33-46
• Main Authors: Mañanes, Rafael, Bruno, M., Alonso, J., Fraguela, B., Tejedor, L.
• Format: Article
• Language: English
• Subjects: Coastal oceanography, estuaries. Regional oceanography; Earth, ocean, space; Exact sciences and technology; External geophysics; Marine; Physics of the oceans
• ISSN: 0399-1784
• DOI: 10.1016/S0399-1784(98)80047-9

The present work establishes clear relationships of the amplitude and phase variation of the barotropic M 2 signal in the velocity of the current with the barotropic subinertial flow in the Strait of Gibraltar. The analytical procedure is applied on data from Gibraltar Experiment in order to obtain barotropic subinertial series and the amplitude and phase variation of the M 2 signal series involves harmonic analysis, empirical orthogonal function analysis and complex demodulation. In addition, cross-spectral analysis has been applied to study these relationships, concerning which non-linear interaction between M 2 and the subinertial oscillation is proposed as the responsible physical mechanism. An analytical solution characterizing this type of non-linear interaction is offered in explanation of the experimental results. Le présent travail établit les relations entre l'amplitude et les variations de phase du signal barotrope M 2 dans le détroit de Gibraltar et le flux barotrope subinertiel. Les séries de données sont traitées par un ensemble de méthodes : analyse harmonique, analyse des fonctions orthogonales empiriques, démodulation complexe et analyse spectrale croisée. Le mécanisme physique responsable des relations entre le signal M 2 et l'oscillation subinertielle est l'interaction non linéaire. Une solution analytique de ce type d'interaction explique des résultats expérimentaux.