Wave dynamics over Roberts Bank, British Columbia: processes and modelling (original) (raw)
Between 1 March and 26 March 2002, a wave and current measurement station was deployed on the upper delta slope of Roberts Bank in approximately 12 m of water. The field data were analyzed and used in a parabolic wave model to determine wave characteristics for fair-weather, moderate, and storm conditions. The model shows that storm waves act nonuniformly along the beach depending on the local morphology and tidal elevation. Waves propagating during high tide are characterized by smooth dissipation and progressive refraction, whereas waves propagating during low tide show intense refraction and breaking in front of or over a low-tide bar. Sediment transport divergence in the nearshore is strongly controlled by the temporal relationship between storm waves and tidal height. Résumé : Entre le 1 er et le 26 mars 2002, une station instrumentée a été déployée sur la partie supérieure de la pente deltaïque du banc Roberts, dans approximativement 12 m d'eau, afin de mesurer la houle et les courants. Les données de terrain ont été ensuite analysées et utilisées dans un modèle parabolique de houle afin de déterminer les caractéristiques des houles pendant les conditions de beau temps, modérées et de tempête. Le modèle montre que les houles de tempête agissent non uniformément le long de la plage selon la morphologie locale et le marnage. La propagation de la houle à marée haute est caractérisée par une légère dissipation et une réfraction progressive tandis que les houles se propageant à marée basse montrent une intense réfraction et déferlent sur le front ou au-dessus d'une barre de marée basse. La divergence du transport sédimentaire dans la zone littorale est fortement contrôlée par la relation temporelle entre les houles de tempête et le niveau de la marée.
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