The University of Eastern Finland, the Finnish Meteorological Institute and the University of Helsinki participated in a study where the capability of Earth System Models (ESMs) to simulate the impact of biogenic aerosols on cloud properties was analyzed. We used two long-term observational datasets from boreal and tropical forests, together with satellite data, to evaluate the simulated processes related to the BVOC-aerosol-cloud feedback. The feedback was detectable in observations on both locations, and this is the first time it was presented for tropical forests. The evaluation of four ESMs showed that the weakest modelled feedback estimates are likely too low, but compensating errors make it difficult to draw conclusions of the strongest estimates. Overall, the method of evaluating along process chains shows promise in pin-pointing sources of uncertainty and constraining modelled aerosol feedbacks.
Reference: Blichner, S.M., Yli-Juuti, T., Mielonen, T. et al. Process-evaluation of forest aerosol-cloud-climate feedback shows clear evidence from observations and large uncertainty in models. Nat Commun15, 969 (2024). https://doi.org/10.1038/s41467-024-45001-y