Aerosol-radiative forcing associated with fire-driven dust emissions in a changing environment

• Applicant: Professorin Dr. Kerstin Schepanski
• Subject Area: Atmospheric Science
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 432456920

Mineral dust aerosol particles, tiny soil particles that are mobilized and eventually entrained into the atmosphere by winds from sparsely vegetated or barren soil, are a significant contributor to the global aerosol burden. Suspended in the atmosphere and dispersed by prevailing wind systems, mineral dust particles interact with radiation hence impacting the Earth radiation budget. They further stimulate cloud and precipitation formation processes which ultimately affects the atmospheric water cycle. Once removed from the atmosphere by sedimentation and deposition processes, mineral dust particles may stimulate the ecosystem’s bio-productivity eventually impacting the carbon and nutrient cycle. Besides the classical view of mineral dust entrainment by atmospheric winds (e.g., wind erosion), mineral dust particles are can be entrained by fire-driven winds and pyro-convective updrafts as they occur in wildfires and their vicinity. In the light of the global atmospheric dust burden, fire-driven dust emission represents an additional dust entrainment mechanism eventually resulting into higher atmospheric dust concentrations consequently altering the dust radiative forcing and hence the dust associated feedbacks on e.g., radiation, clouds, and ecosystems. With regard to the modulating role of wildfires for mineral dust emission, two major impacts can be observed: (i) dust entrainment during active wildfires via fire-driven dust emission processes, and (ii) dust entrainment from post fire surfaces via wind-driven dust emission processes. As both impact on the atmospheric dust concentration and hence the magnitude of dust radiative forcing, this research project aims at quantifying the role of wildfires on the atmospheric dust concentration. In order to achieve this, we propose to explicitly regard fire-associated dust emission processes (fire-driven and wind-driven) in the framework of an atmosphere-aerosol model. Being able to quantify and eventually assess the role of wildfires for the atmospheric dust concentration will ultimately improve our estimates on aerosol radiative forcing, a key parameter for understanding the past, current, and future climate.

• DFG Programme: Research Grants