Entrainment and Mixing Processes and Their Effects on Cloud Microphysical Relationships in Stratocumulus Clouds Measured during the ACE-ENA Campaign

The entrainment and mixing of clear and cloudy air has been considered as one of the important processes that may explain the gap between theoretical and observational droplet spectral broadness. However, it is difficult to identify what the dominant mixing mechanism is and what the controlling factors of such mechanism are because what we observe are results of complex interactions of thermodynamical, cloud microphysical, and dynamical processes. Our recent studies on stratocumulus clouds showed that cloud microphysical relationships suggest homogeneous mixing (HM) trait of positive correlation between liquid water content and mean volume diameter (i.e., droplets are smaller in diluted portion of cloud). We speculated that this is due to vertical circulation mixing of entrainment affected cloud parcels near cloud top that may have changed the cloud microphysical relationships to suggest HM. To confirm this speculation, it is necessary to analyze the relationships between cloud microphysical, dynamic, and thermodynamic variables at various altitudes, from cloud base to top. Here we try to make investigation on marine stratocumulus clouds observed in the Aerosol and Cloud Experiments in Eastern North Atlantic (ACE-ENA) campaign. We focus on highlighting the characteristics of cloud microphysical relationships and the effects of entrainment and mixing processes at various altitudes. Our aim is to reveal the implication on entrainment and mixing processes and vertical circulation mixing in these clouds. More detail will be presented at the conference.