Effects of meteoric debris on stratospheric aerosols and gases

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Abstract
We consider the interactions of meteoric dust particles and metal vapors with stratospheric aerosols and gases. We utilize the detailed calculations of meteor ablation and recondensation rates made by Hunten et al. (1980) to obtain a fairly precise characterization of meteoric dust height and size distributions. We quantify the contribution of meteor residues to aerosol composition, the role of meteoric dust as condensation nuclei, and the effects of meteor debris on aerosol size distributions. We give estimates of particle surface areas, and discuss the potential importance of heterogeneous chemistry for stratospheric trace gases. We also investigate the interaction between H2SO4 vapor, which is associated with stratospheric aerosols, and meteor metal vapors, which are responsible for stratospheric metal ion composition. Our model predictions compare favorably with observational data on the elemental composition of aerosols, stratospheric particle size distributions, condensation nuclei abundances and sulfate mass mixing ratios. We conclude that meteoric particles may dominate the natural stratospheric aerosols at small (1.0 μm) sizes under normal conditions. We show that metallic meteoric elements may act to neutralize sulfuric acid vapor above 20 km, significantly reducing ambient H2SO4 abundances. We also demonstrate that model calculations which neglect particle interactions can seriously overestimate stratospheric metal vapor concentrations.