Examination of cloud microphysical relationships and their implication on entrainment and mixing processes in stratocumulus clouds measured during the ACE-ENA Campaign

 

Authors

Jae Min Yeom — Michigan Technological University
Seong Soo Yum — Yonsei University
Jian Wang — Washington University in St. Louis
Raymond A Shaw — Michigan Technological University
Fan Mei — Pacific Northwest National Laboratory
Beat Schmid — Pacific Northwest National Laboratory
Alyssa A. Matthews — Pacific Northwest National Laboratory

Category

Microphysics (cloud, aerosol and/or precipitation)

Description

Marine boundary layer clouds such as stratus and stratocumulus clouds are known to play a critical role in the Earth’s radiation budget with their extensive coverage. Despite the simple shape of such clouds, the relationships between cloud microphysical, dynamical, and thermodynamic variables are complicated in these clouds. Especially, entrainment and mixing of entrained air from above cloud top with cloudy air is considered as one of the most important process that can modulate cloud microphysical relationships differently depending on how mixing proceeds. Our previous studies found that cloud microphysical relationships vary with altitudes speculatively due to vertical circulation of cloud parcels affected by entrainment and mixing. Here we make investigation on marine stratocumulus clouds observed during the Aerosol and Cloud Experiments in Eastern North Atlantic (ACE-ENA) Campaign by using a new approach. The cloud microphysical relationships and new diagram analysis suggest inhomogeneous mixing near cloud top but as the altitude goes down, they show the trait of homogeneous mixing. The magnitude of the slope between log L (liquid water content) and log τp (phase relaxation time scale) in the new diagram analysis decreases steadily with distance from cloud top. Such behavior in these clouds seems to be consistent with vertical circulation mixing, as speculated in our previous studies. More detail will be presented at the meeting.