Couplage d'un modèle de neige avec un modèle de climat

Coupling a multi-layered snow model with a GCM

¹ Centre d'Etudes de la Neige, Météo-France : CNRM
² National Institute of Meteorology and Hydrology, Bulgarian Academy of Science

Abstract

A multi-layered snow model, including most physical processes governing the evolution of snowpacks, has been coupled to a GCM to improve the represeniation of snow cover in climate simulations. The snow model, called Crocus, includes original features to simulate the evolution of snowpack layering which allows a realistic calculation of sonow albedo as a function of the type and size of the crystals of the surface layer. The coupling scheme is based on a synchronous run of the GCM and of the snow model with an exchange of the surface fluxes at every time step. It was tested in a 5 year run at a T42 resolution. The impact on the atmosphere was important over most covered regions and the sonowpacks simulated in the different regions present a layering which is realistic and very variable in connection with the climate. The simulated snow cover compares satisfactorily with the present snow climatology.