Impact of Wildfires on Mineral Dust Emissions in Europe. Issue 24 (16th December 2022) - Menut, Laurent
Abstract: Mineral dust emissions mainly depend on soil erodibility and near‐surface wind speeds. During biomass burning episodes, pyroconvection locally generates high surface wind speed and non‐desert surfaces (such as forest and shrubs) are partially replaced by barren soil. These effects may induce additional mineral dust emission. However, they are generally not taken into account in chemistry‐transport models since the biomass burning and mineral dust emissions are usually considered as independent processes. This may lead to an underestimation of the mineral dust emissions and therefore of the transported concentrations. In this study, this link is added in the CHIMERE chemistry‐transport model. The summer of 2021 is modeled over Europe using the coupled WRF‐CHIMERE system. Simulations with and without the link between emission processes are performed. Results are compared to observations such as surface measurements of ozone and particulate matter by EEA and aerosol optical depth by AERONET. With more emitted mineral dust, an effect is found on the whole meteorological and chemical system: wind, temperature, cloud, gas (such as ozone with a few ppb changes) and aerosol concentrations are changed. The effect does not appear to be very important but significant enough to have to be taken into account in future modeling. Plain Language Summary: Biomass burning inject pollutants into the atmosphere but also change meteorological and surface characteristics. During the fire, forced convection can drive mineral aerosols aloft. After the fire, the burned surface becomes more erodible. To account for these interactions between fire and mineral dust emissions, we have developed a new parameterization in the coupled WRF‐CHIMERE model. We quantify the impact of this interaction and show the regions in Europe where it adds erodible surfaces. Key Points: Wildfires emissions create erodible surfaces and enhanced mineral dust emissions Additional mineral dust emissions are modeled over western Europe with the WRF‐CHIMERE online regional modeling The impact of these additional emission have an impact on meteorology and other gas and aerosol concentrations via the direct and indirect aerosol effect