Modelling and analysis

Modelling and analysis

Members of the Centre for Atmospheric Chemistry work with a variety of models applied to problems at local, regional and global scales. We study the emissions, atmospheric chemistry and transport pathways of atmospheric trace gases and aerosols from natural and anthropogenic origins. We are interested in understanding the atmospheric composition of Australia and the Southern Hemisphere, and use the models to interpret ground-based and satellite measurements of diverse species.

Contacts: Dr Jenny Fisher, Dr Nicholas Deutscher

GEOS-Chem

GEOS-Chem is a global, 3-D chemical transport model that now can also be run as a regional model for Australia. It is driven by meteorological fields from the NASA Goddard Earth Observing System and includes a state-of-the-science description of trace gas and bulk aerosol sources, sinks, and chemistry. Current GEOS-Chem projects include:

  • Understanding the impact of long-range pollution transport on the Australian atmosphere
  • Constraining the emissions and chemistry of biogenic volatile organic compounds in Australia
  • Interpreting shipborne measurements of trace gases from circumnavigation of Australia
  • Understanding the biogeochemical cycling of mercury in Australia and the Southern Ocean
  • Using GEOS-Chem to contribute to the development of the ACCESS Earth System Model.

Contact: Dr Jenny Fisher

STILT

STILT (Stochastic Time-Inverted Lagrangian Transport model) is a Lagrangian particle dispersion model (LPDM) for atmospheric transport. STILT derives the upstream influence regions at one or more measurement locations. Therefore, it is a fast tool to determine the sensitivity of atmospheric tracer mixing ratio measured at receptor points with respect to upstream surface fluxes. STILT is driven by meteorological fields (e.g. wind fields) from a variety of weather prediction models such as ECMWF or WRF, enabling it to be used for forecasting or for analysis of past observations.

A current application of STILT is for the understanding regional scale budgets, where STILT is used in conjunction with high resolution emission inventories and biospheric flux models. At the University of Wollongong, we use STILT to understand the regions and processes that influence our in-situ and remotely-sensed measurement data of greenhouse gases and trace gases.

STILT is actively developed by a group of researchers at Harvard University, MPI-Jena, University of Waterloo, and Atmospheric & Environmental Research (AER).

Contact: Dr Voltaire Velazco

WINDTRAX

The WindTrax model is used for interpretation of agricultural emission measurements. The measured concentrations are combined with wind statistical data to calculate emission strengths from an unknown source using a backward Lagrangian stochastic (bLs) model implemented in WindTrax software (Thunder Beach Scientific, University of Alberta, Edmonton, Alberta, Canada). The method has been successfully employed to determine emissions from dairy cows (Laubach and Kelliher, 2004, 2005, 2005a), small groups of corralled beef steers (Bai et al 2008), and feedlots (Loh et al., 2008), where animal density is high and evenly distributed over an area.

Contact: Dr Frances Phillips