Prospects for the Characterization of the Fundamental Parameters Linked to the Energy Spectrum of the Aeolian Sea State in Benin Coastal Zone

Abstract

The Beninese coast, like most coastal regions, is subject to various hydrodynamic factors that are likely to be modified by climate change. On the coast, the coasts are constantly subject to the action of waves, currents and wind. This work, carried out near the port of Cotonou, aims to provide representative statistics on the direction of the fundamental parameters of the wind seas, their height in the area close to the coast, where the swell is not yet subject to the action of the funds. Based on in situ data measurements with mooring systems at tide gauge - meteorological stations during the hydrodynamic measurement campaign and carried out at 10-minute time steps, on a regular basis over a period of four consecutive years by NORTECKMED in collaboration with the Millenium Challenge Account (MCA-Benin) within the framework of the extension of the Autonomous Port of Cotonou, the statistical distribution of the characteristic parameters of the waves (height, direction of propagation and period) is elaborated. Thus, the significant height Hs , the peak period or the stable average wave period Tp  ≈ Tms and the most frequent direction of propagation Dp are evaluated. A frequency characterization of the period Tc , the wavelength Lc and the height Hc of short swells, generated by local winds, is obtained using the Pierson-Moskowitz frequency spectrum. In short, the four years of data made it possible to carry out statistical production and simulations of wind, tide and wave data in order to determine the significant heights Hs , the peak period  Tp, the linear energy power available and the link between Hs and  Tp according to the Beaufort scales. Likewise, we made a characterization of short swells (wind seas) based on the value of the local wind speed, the Pierson-Moskowitz frequency spectrum and a representation of the wave propagation directions.