PUMAS microphysics

The Parameterization of Unified Microphysics Across Scales (PUMAS) is the continued evolution of the MG microphysics scheme, since MG is more than just Morrison and Gettelman who have contributed. The current version in CAM (MG3) contains a rimed ice hydrometeor (graupel or hail) so is a 2 moment (Mass, Number) and 5 class (Liquid, Ice, Rain, Snow, Graupel) bulk microphysics scheme. PUMAS now has its own github repository and is being pulled into CAM as an external. Development will move to a version compatible with the CCPP. Additionally we are trying to unify the Ice and Snow phase into a single class, to remove artificial boundaries between suspended and falling ice. This 'unified ice' version is in development.

Versions of PUMAS (As MG2 or 3) are currently in use in E3SMv1 and GISS Model-E.

Gettelman et al. (2020) Evolution of CESM Cloud Microphysics: Parameterization of Unified Microphysics Across Scales (PUMAS). 2020 CESM workshop. View presentation PDF

Figure: Southern Ocean Cloud Studies (SOCRATES)

Code Repository

For updated code status visit:

Project Contact

• Andrew Gettleman [ andrew@ucar.edu ]