Représentation des nuages chauds dans le modèle météorologique MERCURE

A two-moment semi-spectral warm microphysical scheme has been implemented inside the meteorological model “MERCURE” of the EDF company. In particular, in this scheme, a new formulation of the buoyancy flux (<w’θv’>) is proposed, which is coherent with the corrigendum of Mellor (1977) but differs from Bougeault (1981). As for the validation the model, the non- precipitating cloud microphysics is validated by comparing the numerical simulations of fifteen cases of cooling tower plumes with data from a measurement campaign in Bugey nuclear power plant in 1980. Satisfactory results are obtained on the plumes shape, on the temperature and vertical velocity fields and on the droplets spectrums, although the liquid water contents tend to be overestimated. The precipitating cloud microphysics is tested by reproducing the academical cases of orographic precipitation of Chaumerliac et al. (1987) and Richard and Chaumerliac (1989). The precipitating cloud simulations allow to validate the model as well as the impact of the different microphysical terms on the rain intensity.