Modeling the Effect of the Mineralogical Composition of Dust on the Heterogeneous Uptake of SO2 and HNO3 on Dust Particles in NASA GISS ESM ModelE

As a major aerosol in Earth's atmosphere, mineral dust plays an important role in biogeochemical cycles and weather and climate variability. During transport from the dust sources to remote regions, dust particles can react with trace gases in the atmosphere, changing the physical and chemical properties of the particles ("aging" of dust), e.g., by making the dust more soluble. The efficiency of the uptake of trace gases on the dust surfaces depends on the mineralogical composition of the dust particles, and it can differ by orders of magnitude between the different minerals. However, owing to the large computational burden that comes with taking into account individual mineral species, most global models distinguish different dust sizes, but otherwise assume globally uniform physical and chemical properties of dust. The National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies (GISS) Earth system model ModelE is one of the few global models where the mineralogical composition of dust is being simulated as an optional physics version. The dust module distinguishes eight mineral species (illite, kaolinite, smectite calcite, quartz, feldspar, hematite, and gypsum) as well as internal mixtures of hematite with the other minerals. The dust minerals can be simulated together with other prognostic aerosol types, and the model also includes heterogeneous chemistry, a thermodynamic equilibrium model, and photolysis code. In this update to previous work, preliminary results are presented from simulations with the model, for which mineral dependent coefficients for the uptake of SO₂ and HNO₃ on the dust surface are taken into account. Three cases of simulations are compared, a case without heterogeneous uptake, a case where the uptake coefficients are the same for all mineral types, and a case where the uptake coefficients depend on the mineral type. It is being evaluated whether the results depend on the degree of complexity taken into consideration.