Aerosols and Chemistry
Aerosols
CCAM supports both prescribed aerosol and prognostic aerosol models. Prescribed aerosols was typically used for CMIP3 experiments, whereas prognostic aerosols are used for CMIP5 experiments. A description of the parameterisation can be found at rotstayn2002_aerosols.pdf and rotstayn2011_aerosols.pdf. Note that the model now also supports a prognostic sea-salt parameterisation.
The (single moment) prognostic aerosols (iaero = 2 or -2) is based on the CSIRO Mk3.6 aerosol scheme, but modified to couple to the CCAM physical parameterisations. The model includes direct effects when coupled to the SEA-ESF radiation scheme and indirect effects when coupled to the LDR cloud microphysics. The main aerosol species are
- sulphur cycle – DMS, SO2, SO4
- Carbonaceous aerosols – Hydrophobic organic carbon, hydrophilic organic carbon, hydrophobic black carbon and hydrophilic black carbon
- Dust – For bins of dust corresponding to different particle sizes
- Sea salt – jet and film modes
Carbon cycle
CCAM supports a terrestrial carbon cycle model CASA-CNP. This model requires the CABLE land-surface model to function. When activated, CASA-CNP can be used to predict the model Leaf Area Index (LAI) based on the carbon cycle.