Investigation of Cloud Nucleation Activity of Regional Dust Samples using Adsorption Activation Theory and CCN Measurements
In this work, we present improvements in current understanding of mineral dusts interactions with clouds by coupling laboratory CCN activation measurements of regional dust samples with advancements in numerical parameterizations to describe dust-cloud interactions in global aerosol climate models. The mineral dusts investigated include samples from Northern America, African, and East Asian soils. To assess the role of the mineralogy on dust CCN activity, we also perform measurements with the most abundant individual minerals (clays and carbonates). The results obtained from these measurements are used to constrain a new droplet formation parameterization that explicitly accounts for "adsorption activation" using the multilayer Frenkel-Halsey-Hill (FHH) adsorption isotherm model modified to account for particle curvature (Kumar et al., 2009). A comparison of different aerosol-water vapor interaction mechanisms (traditional Köhler theory vs adsorption activation theory) is then carried out focusing on the potential differences in CCN number, parcel maximum supersaturation and cloud droplet number.