A numerical convective cloud model with detailed microphysics which
includes the equations of motion, thermodynamic and an equation for the raindrop spectra
is presented. The model considers the variation of the spectra by activation,
condensation, coalescence, breakup, deposition and advection. Numerical simulations in
order to show the variation of the spectra by condensation and by coalescence are
presented, which demonstrate the importance of the coalescence in the formation of
precipitation. Finally the raindrop spectra are compared with the experimentally obtained
Marhall-Palmer type distributions. A good correspondence between the observed and the
simulated case is observed.
