Simulation of Distributions and Radiative Impacts of Biomass-burning Aerosols

摘要

Distributions and climate impacts of biomass-burning aerosols were simulated by a global aerosol climate model, SPRINTARS, which was fully coupled to a general circulation model. The model included calculations of the direct, semi-direct and indirect effects of aerosols. Seasonal variations of mass concentrations of the main biomass-burning aerosols in the atmosphere, i.e., black carbon, organic matter and sulfate, were simulated well around burned regions. The global annual mean radiative forcing by biomass-burning aerosols was thereby calculated to be - 0.07 W m~(-2) at the top of the atmosphere (TOA) and - 0.23 W m~(-2) at the surface through the direct effects. The results indicate that aerosols have sufficient effects to change regional climates through strong, negative direct radiative forcing over biomass-burning regions. The global mean radiative forcing of the indirect effects due to biomass-burning aerosols is estimated to be nearly 0 W m~(-2). This implies cancellation between the cooling effect of reducing cloud droplet size and warming effect of promoting conversion from supercooled water to ice crystals. A weekly aerosol forecasting system with SPRINTARS includes information on daily aerosol emissions from biomass burning retrieved from MODIS hotspot data.