Linking Dust Mineralogy and Ice Nucleation in Mixed-Phase Clouds in EC-Earth4

Aerosols play a central role in regulating cloud microphysical processes and climate through their ability to act as ice-nucleating particles (INPs). Mineral dust is a dominant global INP source, with laboratory and field studies demonstrating that specific mineral phases—most notably K-feldspar and quartz—control ice formation in mixed-phase clouds. This motivates their explicit representation in Earth system models seeking to reduce uncertainties in aerosol–cloud interactions.

Building on the fundamental aerosol–cloud interaction framework implemented in EC-Earth3, we present recent advances in the representation of mineral dust emissions and heterogeneous ice nucleation in the OpenIFS 48r1 atmospheric model, as part of the development pathway towards EC-Earth4. We introduce a new mineral dust emission scheme that explicitly resolves dust mineralogy using global mineralogical atlases. The scheme calculates the atmospheric abundance of individual dust minerals and incorporates key land surface controls—vegetation, soil type, and potential sources—allowing more realistic dust simulations and hence potentially improving projections of future climate impacts.

The model allows flexible selection among state-of-the-art mineralogical datasets, including the new NASA EMIT mineral map, which enables sensitivity studies of mineral-specific INP activity. Model performance is evaluated and calibrated against long-term dust surface concentration measurements from global and regional observational networks, while simulated aerosol optical depth is compared with observations from dust-dominated ground-based stations to constrain dust loading and transport.

INP concentrations are further evaluated by applying mineral-specific laboratory-based ice-nucleation parameterizations to the simulated mineral dust fields over a range of temperatures. This enables direct assessment of how different mineral phases contribute to INP concentrations and provides a benchmark for future fully coupled aerosol–cloud simulations.

Together, these developments establish a more physically consistent and mineralogy-aware representation of dust–cloud interactions in EC-Earth4, supporting improved quantification of aerosol-driven uncertainties in cloud feedbacks and climate sensitivity.