Nesting Of ROMS For Climate Change Studies In The Gulf Of Lion

William Cabos, Maria Jose Ortiz Bevia, Irene Perez
Physics Department, Alcala University, Spain


The global coupled climate simulations used for the IPCC reports give us an insight about the impacts of Climate Change in a global scale, but their relatively coarse resolution do not allow to study in detail the local impacts. Regional Climate Models at higher resolution can be used to solve this problem and to resolve better such features as the precipitation, orography and coastal phenomena. The data from the Global simulations can supply the global patterns of the Atmospheric and Oceanic circulation. It is useful to analyze the impact of the model resolution and boundary conditions in the regional characteristics of the circulation. In this work we compare the results from three simulations carried out with the ROMS model for the ocean circulation in Gulf of Lion region forced with boundary conditions and forcings from the HADCM3 coupled model. The model domain of the first simulation covers the Atlantic basin and the Mediterranean sea with a 1/6 degree resolution. This domain includes all the Iberian Peninsula coasts. In this simulation we use the Agrif (Adaptive Grid Refinement In Fortran) package in order to attain a resolution of 1/18 degree in the Gulf of Lion region. For this simulation we use the Orlanski open boundary conditions. For the second simulation we use the Agrif package in the same domain, but the open boundary conditions for the more extended domain are specified from the global model. Finaly, the last simulation covers only the Gulf o Lion region, with specified boundary conditions from the global model.