Unstructured Finite Volume Solver for the Computation of the Residence Time in the Nador Lagoon, Morocco

Using the concepts of the Constituent-oriented Age and Residence time Theory (CART, https://www.climate.be/cart ), we compute timescales related to the water renewal in semi-enclosed domains. The modeling system is based on an Eulerian approach and consists of two coupled model components: (i) the shallow-water equations for the hydrodynamical model and (ii) a transport equation for the passive tracer. The full system is incorporated into a high order finite volume solver for unstructured meshes. Advection is approximated by a Non-Homogeneous Riemann Solver (SRNH) which can handle topographic variations. Our objective is to study recirculation problems in the Nador lagoon (Morocco) and, in particular, measure the residence time of water inside the lagoon. An adequate numerical study would determine the necessity and indeed the eventual location of other passes between the lagoon and the Mediterranean, permitting the residence time of a given tracer to be reduced.