Oceanic DMS strongly affects aerosols and clouds in the Arctic
Résumé
Arctic aerosol, cloud, and surface radiation budgets are highly sensitive to how dimethylsulfide (DMS) is represented in atmospheric models. We investigate the impact of (1) the gas-phase DMS oxidation mechanism (simple versus complex), (2) the representation of oceanic DMS (global climatology versus detailed Arctic Ocean biogeochemistry simulation), and (3) the parameterization of new particle formation (NPF) from methanesulfonic acid (MSA). We find that the more detailed approach in (1) and (2) improves agreement with observed DMS and SO2 concentrations, and that activating (3) enables the model to capture the observed summertime maximum in aerosol number concentrations. Together, these changes result in large-scale modifications to cloud microphysics and the arctic surface energy budget, with radiative impacts of ±13Wm-2 annually, reaching up to ±50Wm-2 in summertime when combining all the model updates.
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