A new convective cloud field model based on principles of self-organisation

[摘要] A new cumulus convection parameterisation is presented in this paper.The parameterisation uses an explicit spectral approach and determines,unlike other convection schemes, for each convection event a new clouddistribution function regarding to the given vertical temperature andhumidity profiles.This is done by using a one dimensional cloud model to createa spectrum of different clouds. The interaction between all non convectivephysical processes in the AGCM and all different clouds is takeninto account to calculate a selfconsistent cloud spectrum.The model has been implemented in the ECHAM5 AGCM and tested againsta large eddy simulation model.The representation of a shallow cumulus cloud field by the AGCMcould be much improved. Diurnal cycle, cloud cover, liquid waterpath and the vertical structure of the mass flux, determined by thenew convection scheme are close to the large eddy simulation,whereas the standard convection scheme failed in simulatingthis convection episode.

[学科分类] 大气科学