Modeling mineral dust aerosols in the Arctic with the regional model WRF-Chem 4.6.1

Abstract. Important sources of mineral dust aerosols in the high latitudes, especially in the Arctic, are neglected in most atmospheric models. Here, we create a new description of mineral dust aerosol emissions including high-latitude dust sources, and implement it in a polar version of the WRF-Chem 4.6.1 model. We also improve the representation of mineral dust aerosol deposition processes. A 1-year-long quasi-hemispheric simulation for 2012 is evaluated against observations of surface concentrations and deposition fluxes at the Arctic surface. The updated model predicts 34 Tg yr^-1 of emissions north of 60° N, and our evaluation shows dramatic improvements in model performance compared to the base model, to a state-of-the-art climate model, and to the CAMS reanalysis. We find that high latitude dust sources have significant impacts on several climate-relevant metrics in the Arctic, such as aerosol optical depth, ice nucleating particle concentrations, and especially mineral dust aerosol deposition to snow and ice, where high latitude sources are the main contributor over the Arctic sea ice pack. These results demonstrate the importance of taking high latitude dust emissions into account, provide a description of these sources reusable in other models, and open the way for future work to better estimate the climate impacts of high latitude dust sources.