The CLOUD submodel calculates the processes usually called cloud microphysics.
Via namelist one of the implemented parametrisations can be chosen and the necessary calculations are performed automatically.
At the momentary state the schemes that are implemented are:

  • the original cloud microphysics routine from the ECHAM5 from MPI Hamburg. These routines have been modularised and adapted into the MESSy - structure, but still perform the same microphysical calculations as the original routine. A short description of the processes in the cloud scheme are documented here .
  • the two-moment cloud microphysics routines developed at the ETH Zürich in the group of Prof. U. Lohmann.
    These schemes are included in several versions including updates from both the ETH group, but also other members of the EMAC consortium, e.g. the aerosol-ice interactions have been reformulated according to Barahona and Nenes.
  • In this module the cloud cover schemes of the original ECHAM5 are also implemented (RH scheme and PDF scheme) and these calculations were performed just the same way as in the original.
    In addition to this the cloud droplet number concentration calculation has been moved into this module. This is still the original parametrisation. Furthermore, aerosol activation routines according to Abdul-Razzak & Ghan, Fountoukis & Nenes, and Karydis et al., are implemented to allow for aerosol cloud coupling with the two-moment schemes. Additionally, aerosol-ice interactions are enabled using several activation pathways and schemes.