Most aerosol-cloud-climate assessment studies assume that aerosol with a substantial fraction of soluble material are the sole source of Cloud Condensation Nuclei (CCN). However, insoluble species can also act as good CCN, even if they lack appreciable amounts of soluble material. The source of hygroscopicity in these particles is the adsorption of water vapor onto the surface of the particle. Moreover, during atmospheric transport, fresh dust undergoes aging which results in a coating of soluble material on its surface that augments its CCN activity. Given that dust may affect precipitation in climate-sensitive areas, the ability to capture the complex impact of mineral dust on cloud droplet formation is an important issue for global and regional models. The “unified dust activation framework” of Kumar et al. (2011) can be used to calculate the CCN activity of both fresh and aged dust. In this study, simulations of droplet number are carried out with the GMI chemical transport model. GMI simulates global atmospheric composition which is used to drive the droplet number calculations of Kumar et al. (2011) parameterization. This new framework is a comprehensive treatment of the inherent hydrophilicity from adsorption and acquired hygroscopicity from soluble salts in dust particles and is used to assess the impact of dust and adsorption activation on the predicted global droplet number concentration.
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We would like to acknowledge support from NASA-ACMAP, CONOCO-Phillips, and NOAA.
Considine DB, Bergmann DJ, Liu H (2005) Sensitivity of Global Modeling Initiative chemistry and transport model simulations of radon-222 and lead-210 to input meteorological data. Atmos Chem Phys 5:3389–3406. doi:10.5194/acp-5-3389-2005CrossRefGoogle Scholar
Kumar P, Sokolik IN, Nenes A (2009b) Parameterization of cloud droplet formation for global and regional models: including adsorption activation from insoluble CCN. Atmos Chem Phys 9(7):2517–2532. doi:10.5194/acp-9-2517-2009CrossRefGoogle Scholar
Kumar P, Sokolik IN, Nenes A (2011) Measurements of cloud condensation nuclei activity and droplet activation kinetics of wet processed regional dust samples and minerals. Atmos Chem Phys 11(4):8661–8676. doi:10.5194/acp-11-8661-2011CrossRefGoogle Scholar
Levin Z, Teller A, Ganor E, Yin Y (2005) On the interactions of mineral dust, sea-salt particles, and clouds: a measurement and modeling study from the Mediterranean Israeli Dust Experiment campaign. J Geophys Res 110(D20):D20202. doi:10.1029/2005JD005810CrossRefGoogle Scholar
Liu XH, Penner JE, Herzog M (2005) Global modeling of aerosol dynamics: model description, evaluation, and interactions between sulfate and nonsulfate aerosols. J Geophys Res 110(D18):D18206. doi:10.1029/2004JD005674CrossRefGoogle Scholar
Pringle KJ, Tost H, Pozzer A, Poschl U, Lelieveld J (2010) Global distribution of the effective aerosol hygroscopicity parameter for CCN activation. Atmos Chem Phys 10(12):5241–5255. doi:10.5194/acp-10-5241-2010CrossRefGoogle Scholar