Investigation of the Influences of Entrainment-mixing Processes on Cloud Microphysics Using a New Cloud Parcel Model and Observations

Abstract:

It has been increasingly recognized that turbulence entrainment mixing processes affect cloud properties and aerosol-cloud interactions and need to be represented in climate models; however, the details of their impacts on cloud microphysics remain largely elusive, and poorly represented in climate models. Furthermore, there is large discrepancy between numerical models and observations. This work attempts to address these issues by using a new cloud parcel model that accounts explicitly for entrainment-mixing processes and bin microphysics. The combined effects of entrainment rate, mixing mechanisms, updraft velocity and pre-cloud/entrained aerosol properties (aerosol concentration, mean radius, aerosol standard deviation, and chemical composition) on cloud microphysical properties (e.g., droplet concentration, liquid water content, effective radius, and relative dispersion) will be examined by a suite of numerical simulations considering clouds as an open system. The simulations will be compared against aircraft measurements from shallow cumulus clouds in the context of understanding the impacts of entrainment-mixing processes on clouds and their parameterization in climate models.