[University home]

Centre for Atmospheric Science

The Manchester Aerosol Chamber - Modelling Tools for Chamber Data Interpretation

Thermodynamics: A model of multicomponent inorganic and organic aerosol thermodynamics, ADDEM, has recently been reported (Topping et al., 2005 a, b). Accounting for the effects of particle curvature on composition, the equilibrium phase state of all involatile and semi-volatile components can be predicted at any given gaseous partial pressure of the components. For example, the model can be used to calculate the equilibrium size of multicomponent aerosol at a given relative humidity (as well as the cloud activation properties of the particle). A framework of significantly reduced complexity has been constructed for incorporation of the thermodynamics in large-scale models (Topping et al., 2008 a, b).

Aerosol Microphysics: A coupled model of photochemistry and aerosol microphysics has been introduced (Topping et al., 2008) and is available to investigate the evolution of condensed material under chamber conditions of varying temperature and humidity. The gaseous photochemical schemes available range from simple inorganic plus methane and lumped VOC oxidation to a more complex scheme derived from the MCM. The latter scheme is coupled to one of two aerosol thermodynamics codes, representing the organic components with different degrees of complexity. An additional version of the model exists describing the reactive cycling of halogens through sea salt aerosol particles. This version includes pH-dependent aqueous halogen chemistry.

Specialised coupled models: There are a number of detailed process models which can be used to address various coupled systems. One of particular interest to the chamber studies is the coupled model of aerosol formation and evolution in the photochemical iodine oxide system.