The Impact of biomass-burning Aerosols on the diurnal Characteristics of Convection over the Congo Basin (IAC3)

• Applicant: Professor Dr. Peter Knippertz
• Subject Area: Atmospheric Science
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576424898

Central Africa is unique worldwide in terms of thunderstorm activity (especially in the Congo Basin) and aerosol emissions from biomass burning (especially south of the Congo Basin), but the interactions between these two phenomena are complex and poorly understood. This is partly due to a lack of observations that would allow possible mechanisms to be narrowed down. The project “The Impact of biomass-burning Aerosols on the diurnal Characteristics of Convection over the Congo Basin (IAC3)” has the overarching goal of gaining a more precise understanding of the role of biomass burning aerosols during the transition from the boreal summer dry season with extensive fires to the subsequent rainy season and to decipher the associated physical processes. A particular focus is on the diurnal cycle of the boundary layer, and convective initiation and development. Three essential and fundamentally different processes will be investigated in great detail using satellite data, reanalyses, and station observations, as well as high-resolution model simulations using the ICON(-ART) model: (i) A delay in convective triggering due to aerosol-induced dimming of solar radiation at the surface on days with little cloud cover in the morning, leading to fewer but larger and longer-lived mesoscale thunderstorm clusters (direct effect). (ii) A delay in the dissipation of morning boundary layer clouds due to aerosol-induced heating in the lower free troposphere, which subsequently has similar effects on convection as in point (i) (semi-direct effect). (iii) The change in convective development due to altered cloud-condensation and ice nuclei (indirect effect). This project benefits from several current developments: (i) Direct participation in the ambitious field measurement program of the French project BACCOPA (“Biomass-burning Aerosol, Clouds, COnvection and Precipitation in Central Equatorial Africa”) with aircraft- and ground-based measurements of aerosols and other meteorological variables in the Republic of Congo in September 2026. (ii) A collection of additional, previously little-studied station data in an otherwise very data-poor region. (iii) New satellite data based on new sensors (e.g., EarthCARE, METOP-SG), which will be evaluated in close cooperation with the BACCOPA partners. (iv) High-resolution model simulations with detailed representation of cloud and aerosol processes from BACCOPA and IAC3. The results of this work should contribute to a better understanding of the long-term effects of anthropogenic aerosols on radiation and precipitation development in the region.

• DFG Programme: Research Grants
• International Connection: France
• Co-Investigator: Dr. Christian Barthlott
• Cooperation Partner: Professor Dr. Cyrille Flamant