Modeling the Tide-Induced Modulation of Wave Height in the Outer Seine Estuary

Abstract

GUILLOU, N. and CHAPALAIN, G., 2012. Modeling the tide-induced modulation of wave height in the outer Seine estuary. During the last decades, numerous models have been implemented to investigate the effects of tide on wind-generated surface-gravity waves. The present study analyzes the influences of the tide-induced time-varying water depths and currents on the wave height in the outer Seine estuary (France, English Channel). Two modeling systems based on the coupling of circulation and wave propagation modules are applied at the scales of (i) the English Channel and the North Sea and (ii) the Bay of Seine and the harbor of Le Havre, respectively. Numerical results are compared with field data collected with two current meters and two wave buoys in the access channel to Port 2000 (Le Havre). Predictions exhibit a local increase of 30% of the wave height induced by current refraction at slack tide. On the basis of this local comparison of numerical results with measurements, three mappings of the wave height modified by the (i) tide, (ii) water levels alone, and (iii) currents alone are established at the scale of the outer Seine estuary. The currents have a major influence on the wave height modulating at a tidal frequency the direction of incident waves through refraction. This effect is exhibited along the southern breakwater of the harbor of Le Havre and the vicinity of coastal topographic features of the outer Seine estuary.