GEAWHARI, Mohamed Ali Université Mohammed V-Agdal - Faculté des Sciences, Institut Scientifique - Département des Sciences de la Terre, Maroc , HUFF, Lloyd University of New Hampshire - Center for Coastal and Ocean Mapping, USA , MHAMMDI, Nadia Université Mohammed-V-Agdal - Institut Scientifique - Département Sciences de la Terre, Maroc , TRAKADAS, Athena University of Southampton (UK ) - Centre for Maritime Archaeology - Morocco Maritime Research Group, U.K. , AMMAR, Abdellah Université Mohammed V-Agdal - Faculté des Sciences - Département des Sciences de la Terre, Maroc

A seiche observed in the Larache port, Moroccan Atlantic coast

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An episode of seiche, with peak-to-peak amplitudes of 6 to 11 cm, was observed and recorded in the Port of Larache, Morocco, at the mouth of the Oued Loukkos, using a Sea-Bird Electronics CTD. The CTD measurements, which exhibited characteristics of seiche, were processed to remove the much larger tidal signal and preserve the lower amplitude, higher frequency signal of the seiche. Based on spectral estimates, which were performed using the time series containing both well-defined and ill-defined seiche-like water level variations, the most energetic seiche period was approximately 17.5 minutes. A less energetic seiche period of approximately 70 minutes was also detected. The seiche is possibly sustained by reflections of a propagating gravity wave at points where there are sudden changes in the hydraulic cross-section (depth and/or width) of the Oued Loukkos. The genesis of the observed episode of seiche is unknown, but a likely prospect is that it was engendered by non-linear interaction of the tidal flow with the river bed.

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Seiche , Oued Loukkos , Port of Larache , Morocco

bulletin de l’institut scientifique, section sciences de la terre

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