Evaluation of the lake model FLake over a coastal lagoon during the THAUMEX field campaign

摘要

The THAUMEX measurement campaign, carried out during the summer of 2011 in Thau, a coastal lagoon insouthern France, focused on episodes of marine breezes. During the campaign, three intensive observationperiods (IOPs) were conducted and a large amount of data were collected. Subsequently, standalone modellingusing the FLake lake model was used, first to assess the surface temperature and the surface energy balance,and second to determine the energy budget of the water column at the measurement site. Surface fluxes werevalidated against in situ measurements, and it was determined that heat exchanges are dominated byevaporation. We also demonstrated that the model was sensitive to the light extinction coefficient at Thau, dueto its shallowness and clarity nature. A heat balance was calculated, and the inclusion of a radiativetemperature has improved it, especially by reducing the nocturnal evaporation. The FLake lake model wasthen evaluated in three-dimensional numerical simulations performed with the Meso-NH mesoscale model, inorder to assess the changing structure of the boundary layer above the lagoon during the IOPs more accurately.We highlighted the first time ever when Meso-NH and FLake were coupled and proved the ability of thecoupled system to forecast a complex phenomenon but also the importance of the use of the FLake model waspointed out. We demonstrated the impact of the lagoon and more precisely the Lido, a sandy strip of landbetween the lagoon and the Mediterranean Sea, on the vertical distribution of turbulent kinetic energy,evidence of the turbulence induced by the breeze. This study showed the complementarities between standaloneand coupled simulations.