Processes Controlling the Evolution of Orographic Shallow Clouds during CACTI

Despite decades of active research, a comprehensive understanding of the many internal and external processes that control convective cloud evolution in complex terrain remains elusive. Data collected during the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign provide the unique opportunity to extend previous analyses to a region of the world where convective clouds of all scales have a high frequency of occurrence. In this work we examine the effects of topographically-influenced boundary layer and lower free tropospheric circulations on the evolution of cloud properties and precipitation formation in cumulus and stratocumulus clouds. These clouds were often observed by a variety of in situ and remote sensing instrumentation deployed during CACTI. Observations collected by the multi-frequency radar network consisting of the Ka-band ARM Zenith Radar (KAZR), the Ka-/X- band Scanning ARM Cloud Radar (Ka/X-SACR), and the C-band Scanning ARM Precipitation Radar Version 2 (C-SAPR2), coupled with GOES-16 satellite retrievals are used here to analyze cloud morphology, cloud top temperature and phase, and microphysical structure. Doppler lidar, radiosonde, and radar-derived wind observations are used to characterize the evolution of local circulations. Estimations of radar-retrieved in-cloud turbulence, microwave radiometer retrieved LWP, and surface-based cloud condensation nuclei spectra from the dual-column CCN counter are used to assess the relative importance of kinematic, thermodynamic, and aerosol conditions on accretion and collision-coalescence processes that control cloud droplet growth and warm precipitation formation.