Numerical simulation of the wind influence on bottom shear stress and salinity fields in areas of Zostera noltei replanting in a Mediterranean coastal lagoon

The paper concerns the numerical simulation of the wind influence on bottom shear stress and salinity fields in a semi-enclosed coastal lagoon (Etang de Berre) which is connected to the Mediterranean through a long and narrow channel (called Caronte). Two different scenarios are considered. The first scenario (scen.#1), starting with an homogeneous salinity of S=20 PSU and without wind forcing, studies a stratification process under the influence of a periodic seawater inflow and a strong freshwater inflow from an hydropower plant (250 m3/s). Then, in the second scenario (scen.#2), we study how a strong wind of 80 km/h can destroy the haline stratification obtained at the end of scen.#1. The MARS3D numerical model is used to analyze the 3D current and salinity distribution induced by these three meteorological, oceanic and anthropogenic forcings in this lagoon and in the Caronte channel.The main goal is to determine the bottom shear stress (BSS) in the nearshore areas of Zostera noltei replanting, and to compare it with the threshold for erosion of the bottom sediments for different bottom roughness parameters.The most interesting results concern the four nearshore replanting areas; two are situated on the eastern side of EB and two on the western side. The results of scen.#2 show that all these areas are subject to a downwind coastal jet. The destratification process is very beneficial; salinity always remains greater than 12 PSU for a N-NW wind of 80 km

E. Alekseenko, Bernard Roux. Numerical simulation of the wind influence on bottom shear stress and salinity fields in areas of Zostera noltei replanting in a Mediterranean coastal lagoon . Progress in Oceanography, Elsevier, 2018, 163, pp.147-160. ⟨hal-01813850⟩

Journal: Progress in Oceanography

Date de publication: 01-04-2018

Auteurs:
  • E. Alekseenko
  • Bernard Roux

x >