Quantifying Fire-Driven Dust Emissions Using a Global Aerosol Model

Abstract

Vegetation fires have become increasingly recognized as a potential entrainment mechanism for mineral dust. However, the global importance of this emission pathway remains largely unknown. Based on previous LES investigations, we developed a parameterization that relates the dust emission potential of wildfires to observational data of the fire radiative power and further soil-surface conditions. It was implemented into the aerosol-climate model ICON-HAM and simulations with and without the new emission pathway were conducted for the 10-year period 2004–2013. Fire-dust emissions can account for around 230 (190–255) Tg yr⁻¹, which represents around 18 (15–21) % of the total global dust emissions. These additional emissions originate largely from regions that are typically not known as significant sources of mineral dust. Locally, wildfires can enhance the presence of atmospheric dust particles and on the Southern hemisphere might even surpass other forms of dust emission. Highly dust active fire regions are identified in areas where burning grasslands create suitable emission conditions together with emissive soil types despite rather weak fires, for example, in Eastern Europe or the Central US. Fire-dust emissions are subject to a strong seasonal cycle, mainly driven by the fire activity, following the hemispheric warm and dry seasons. Multi-year comparisons with (dust) AOD observations revealed improvements due to the additional fire-dust emissions, particularly in the most fire-active regions on the Southern hemisphere. Nevertheless, further research and improvements of the parameterization are required to better classify the source areas and their variation with the changing climate and land use conditions.