A comparison of spectral bin and two-moment bulk mixed-phase cloud microphysics

This numerical study investigates the representation of cloud microphysical processes in cloud resolving models and the effects of different characteristics of cloud condensation nuclei (CCN) on the evolution of deep convective storms.A comparison of several simulations is presented obtained by applying a spectral bin method and a two-moment bulk microphysical scheme to a deep convective cloud and a squall line. Both modeling approaches show similar results regarding the vertical structure of the clouds, updraft velocities and surface precipitation as well as the sensitivity of these parameters to changes in CCN characteristics. The simulated isolated cell reveals a strong effect to the variation of CCN concentration on the amount of surface precipitation, while the results for the squall line system depend on the specific treatment of the nucleation process.