Climate models generally underrepresent the warming by Central Africa biomass-burning aerosols over the Southeast Atlantic

The radiative budget, cloud properties, and precipitation over tropical Africa are influenced by solar absorption by biomass-burning aerosols (BBA) from Central Africa. Recent field campaigns, reinforced by new remote-sensing and aerosol climatology datasets, have highlighted the absorbing nature of the elevated BBA layers over the South-East Atlantic (SEA), indicating that the absorption could be stronger than previously thought. We show that most of the latest generation of general circulation models (GCMs) from the sixth phase of the Coupled Model Intercomparison Project 6 (CMIP6) underestimates the absorption of BBA over the SEA. This underlines why many (similar to 75%) CMIP6 models do not fully capture the intense positive (warming) direct radiative forcing at the top of the atmosphere observed over this region. In addition, underestimating the magnitude of the BBA-induced solar heating could lead to misrepresentations of the low-level cloud responses and fast precipitation feedbacks that are induced by BBA in tropical regions.

Automated summary

Research shows that biomass-burning aerosols from Central Africa have a significant impact on cloud properties and precipitation over tropical Africa. However, most current climate models underestimate the absorption of these aerosols over the South-East Atlantic, leading to an inaccurate representation of radiative forcing and precipitation feedbacks in the region.