of Microphysical processes in warm stratocumulus clouds and the Z - LWC relationship

1. Introduction Warm stratiform and stratocumulus clouds cover enormous areas of the Earth and play a crucial role in the radiative balance of the Earth and contribute significantly to precipitation. Microphysical properties of stratiform clouds were measured by research aircrafts in course of several national and international field experiments. Using these data, many useful statistical results, such as relationships between aerosol concentration and cloud droplet concentration, " critical " droplet size above which drizzle formation starts, relationship between cloud depth and drizzle flux were reported (e. found that the radar reflectivity (Z)-liquid water content (LWC) relationship crucially depends on the cloud regimes (e.g. drizzle vs no drizzle). At the same time physical mechanisms leading to these statistical results are not well understood. In this study we propose an approach representing a further development of trajectory ensemble models (TEM). The purpose of this study is to investigate processes of the formation and spatial variability DSD at small time and spatial scales under a given dynamical structure of the STBL typical of both non-drizzling and drizzling clouds. We are going to reproduce the classical concept of the formation of stratocumulus clouds, as a result of air mixing by eddies of different scales in the ABL. Among the questions we address in this study are: a) How does drizzle form in stratocumulus? and b) How is the Z-LWC diagram related to cloud microphysics?