SAPYRO: A Regional Spatio-temporal Model for Estimating Pyrogenic Emissions From Vegetation Fires in Southern Africa

The main goal of this research is to improve the reliability and accuracy of emission estimates from vegetation fires in southern Africa by developing a spatio-temporally explicit model for the 2000 fire season, SAPYRO. Accurate quantification of regional pyrogenic emissions requires the assessment of the intra-seasonal variability of several parameters, including burned area, biomass burned and emission factors. Previous regional emission calclulations have either been based upon anecdotal estimates of these parameters or on annual burned area estimates from remote sensing and late dry season field measurements, thus introducing large errors in the emission estimates. In the described modeling approach the Moderate Resolution Imaging Spectroradiometer (MODIS) burned area product is used to estimate the burned area on a monthly basis. A dynamic fuel load model that models Net Primary Productivity (NPP) and uses field-derived relationships to allocate fuel load types is also used at a monthly time scale. The seasonality of emission factors for trace gases and aerosols is modeled to account for the vegetation moisture content variations during the fire season and the resulting effects on the type and amounts of the produced emissions. In addition, for some atmospheric species, emission factors have been found to depend on the type of ecosystem where the burning takes place, grassland or woodland. Combustion factors also vary within the fire season and are related to the fuel mixture. Conclusions are made concerning which aspects of this modeling approach require further research. This study will contribute to meeting one of the main SAFARI-2000 project research objectives.