Development of a 3-D cloud model with detailed microphysics
Abstract
In order to better understand the formation of intense precipitation which often cause flooding, a three-dimensional warm cloud model with detailed microphysics is under development. This cloud model will be coupled with the non-hydrostatic mesoscale dynamical model of Clark (1973). Currently, this model, with a detailed representation of both aerosols and droplets spectra, does only exist in a two dimensional version (DESCAM (DEtailed SCAvenging Model) developed by Flossmann et al. (1985)) and includes the processes of nucleation, condensation/evaporation, coalescence, break-up, sedimentation and scavenging of the aerosols particles by cloud droplets. Some new numerical methods for the advection scheme and for the coalescence process, and the reduction of the variables number allows us to reduce the integration time to enable the use of this model. In the future this 3D cloud model will be used to simulate two different cases of cloud formation. First, we will simulate the formation of a stratocumulus during the ACE2 campaign and then, the formation and the evolution of a convective cloud over the Cévennes mountains in France. Results will be compared with the observations (in particular aerosols and droplets concentrations for ACE2 and precipitation rate and location for the Cévennes case). In the second case, we will show the impact of the aerosol concentration on the precipitation rate. Such a model will be very useful to test and improve the parameterisations of warm microphysics in bulk models and to show the role of the nucleation of cloud droplets on an aerosol spectrum for the formation of intense precipitation.
- Publication:
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EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....3682L