Effects of meteoric debris on stratospheric aerosols and gases

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 (<0.01μm radius) and large (>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.

An aerosol chamber investigation of the heterogeneous ice nucleating potential of refractory nanoparticles

“…The inherently alkaline nature of metal oxide particles will certainly favour the uptake and condensation of sulphuric acid onto particle surfaces within the Junge layer, and thus lead to a role in the formation of PSCs (Turco et al, 1981).…”

Prognostic Value of Cardiovascular Magnetic Resonance and Single-Photon Emission Computed Tomography in Suspected Coronary Heart Disease: Long-Term Follow-up of a Prospective, Diagnostic Accuracy Cohort Study

“…Many processes in atmospheric environments are controlled by the availability of reactive 20 or catalytic surfaces which originate from outside that atmosphere (Nachbar, et al, 2016, 21 Petrie, 2004, Plane, 2012, Turco, et al, 1981. However, this extraterrestrial material is only 22 partially characterised and understood in terms of these various atmospheric processes.…”

Interactions of meteoric smoke particles with sulphuric acid in the Earth's stratosphere

“…The reasons for an approximate two orders of magnitude depletion at 45 km (compared with the peak at ∼35 km) has long been the subject of debate, with gas-phase chemistry, photolysis and heterogeneous uptake on MSPs/metal atoms being proposed as possible removal processes (Turco et al, 1981;Vaida et al, 2003). A 1-D modelling study of MSPacid interaction (Turco et al, 1981), where chemical neutralisation (resulting from metal atom-acid molecule collisions) was assumed, indicated that a downward metal atom flux of 5×10 6 cm −2 s −1 from the upper mesosphere (equivalent to a global meteoric mass influx of ∼200 tonnes per day) was required to account for the observed depletion in H 2 SO 4 at 45 km.…”

“…MSPs are thought to participate in the nucleation of waterice clouds in the mesosphere (Rapp and Thomas, 2006;Gumbel and Megner, 2009), and also impact on trace vapours such as H 2 SO 4 and HNO 3 throughout the middle atmosphere (Turco et al, 1981;Prather and Rodriguez, 1988;Mills et al, 2005). After MSPs have been transported down from the mesosphere in the winter polar vortex , they are thought to be assimilated in liquid (supercooled) H 2 SO 4 -H 2 O droplets (typically 40-75 Wt % acid composition, radius >100 nm) in the stratospheric aerosol or Junge layer which is located between 15 and 30 km in altitude (Carslaw et al, 1997;Deshler, 2008).…”