Climatic effects of biomass burning

Abstract

We have made a series of general circulation model (GCM) and chemical transport model (CTM) simulations to examine further the consequences of biomass burning. We take a three-pronged approach to this study; (1) examine only the direct short-wave forcing of the smoke clouds by imposing smoke ‘clouds’ in the model, (2) examine the indirect effect of biomass smoke by allowing the biomass smoke to modify the optical properties of existing clouds, reducing the effective (mass) droplet radius, and (3) examine the downstream effect by advecting biomass smoke using semi-Lagrangian transport in the GCM. Preliminary results from the GCM simulations suggest strong local coolings (2–4°C or more) where biomass burning occurs with somewhat reduced regional coolings. Initial results of the transport of smoke by the Australian National University CTM (ANU-CTM) show the biomass smoke to remain fairly localized with the advection of smoke extending the effects downwind.