Abstract for presentation at 14th IUAPPA World Congress

Fine Particulate Matter from Biomass Burning in the Top End of Australia: Estimating Emissions and Air Quality

  • Ashok Luhar, CSIRO Marine and Atmospheric Research, Australia
  • Dr Mick Meyer, CSIRO Marine and Atmospheric Research, Australia
  • Dr Ross Mitchell, CSIRO Marine and Atmospheric Research, Australia
  • Susan Campbell, CSIRO Marine and Atmospheric Research, Australia
  • Dr John Gras, CSIRO Marine and Atmospheric Research, Australia

    • We investigate the emission and transport of biomass burning aerosol across the Top End of Australia. We use a fuel load distribution map coupled with satellite-derived imagery of fire scars and hot spots and a diurnal variation of fire potential to estimate hourly emission rates of PM2.5 for the dry season April – November 2004 at a resolution of 1 km x 1 km. These emissions are then used in a three-dimensional meteorological and air pollution model called TAPM, and the model results on PM2.5 concentration and aerosol optical depth are compared with satellite and ground-based measurements. This exercise also seeks to fine-tune and validate the emission calculation methodology. Overall, the model is able to describe the measurements satisfactorily, considering the issues associated with the model resolution, emission uncertainty, and modelled meteorology. The modelled concentrations show that there are exceedences of the Air NEPM for PM2.5 in virtually all locations over land, including Darwin. Estimated top of atmosphere radiative forcing due to aerosol shows a seasonal mean of – 1.8 W/m2, with a region of strong enhancement over the western portion of the Top End. The directional distribution of aerosol leaving the Top End varies from north-westerly during the early months of the dry season, to mainly south westerly towards the end of the dry season, with implication for aerosol impacts elsewhere. The paper demonstrates that integration of modelling with data from various streams is a powerful tool for both air quality and climate applications related to biomass burning aerosols.

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