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Smoke and Dust Particles of Meteoric Origin in the Mesosphere and Stratosphere
626
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1980
Year
EngineeringEarth ScienceGeophysicsHigh Temperature AerosolAblated MassAtmospheric ScienceMicrometeorologyMeteoric OriginMeteoriticsMeteorologyAerosol FormationAtmospheric InteractionHeight ProfileRadiation MeasurementDust ParticlesDust ScienceSpace WeatherAtmospheric RadiationSurface AreaAtmospheric Process
The ablated mass profile from meteors peaks at 84 km. The study proposes that meteoric smoke particles may nucleate sulfate particles, influence noctilucent clouds, scavenge metallic ions, and affect other aeronomical processes. The authors calculate a height profile of ablated meteoric mass using a 10⁻¹⁶ g cm⁻² s⁻¹ flux and the Southworth–Sekanina velocity distribution, compute micrometeorite fluxes, model coagulation of evaporated silicates into smoke particles with a stratospheric sulfate layer framework, and perform numerous sensitivity tests. The model predicts a sharp cutoff of smoke particles above 90 km, a nearly constant surface area of 10⁻⁹ cm² cm⁻³ from 30 to 85 km, negligible optical scattering, and indicates that only processes with ~day collision times are affected, with some support from balloon measurements.
A height profile of ablated mass from meteors is calculated, assuming an incoming mass of 10−16 g cm−2 s−1 (44 metric tons per day) and the velocity distribution of Southworth and Sekanina, which has a mean of 14.5 km s−1. The profile peaks at 84 km. The fluxes of micrometeorites and residual meteoroids are also calculated. The coagulation of the evaporated silicates into “smoke” particles is then followed by means of a model adapted from a previous study of the stratospheric sulfate layer. Numerous sensitivity tests are made. Features of the results are a sharp cutoff of the particle distribution above 90 km, and a surface area close to 10−9 cm2 cm−3 all the way from 30 to 85 km. Some confirmation is obtained from balloon studies of condensation nuclei, although the various measurements differ greatly. The optical scattering and extinction am shown to be undetectable. Several potential applications are suggested: nucleation of sulfate particles and noctilucent clouds, scavenging of metallic ions and atoms, and perhaps other aeronomical effects. The latter are limited to processes that can be influenced by a collision time of the order of a day.