Modelling of the Ebro River plume. Validation with field observation

Abstract

The spreading of the plume induced by the freshwater discharge from the Ebro River into northwestern Mediterranean coastal waters was modelled using two numerical codes. The coastal current field was obtained with a finite difference hydrodynamic model based on a steady-state version of the shallow-water equations, whereas the freshwater dispersion was calculated with a Lagrangian code that solves the 3D convection-diffusion equation and reproduces turbulent diffusion using a "random-walk" algorithm. The agreement obtained between numerical results, satellite observations and field measurements allows an analysis of the more relevant physical mechanisms and the corresponding "tuning" of the two models. The results show that local hydrodynamics near the river mouth, and consequently the spreading of the river plume, are highly dependent on the driving river discharge and wind field characteristics.