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Geophys Res Lett. 2015 Aug 16;42(15):6518-6525. Epub 2015 Aug 13.

On the size and velocity distribution of cosmic dust particles entering the atmosphere.

Author information

1
School of Chemistry University of Leeds Leeds UK.
2
School of ChemistryUniversity of LeedsLeedsUK; National Centre for Atmospheric ScienceUniversity of LeedsLeedsUK.
3
Department of Space Studies Southwest Research Institute Boulder Colorado USA.
4
Space Weather Laboratory GSFC/NASA Greenbelt Maryland USA.

Abstract

The size and velocity distribution of cosmic dust particles entering the Earth's atmosphere is uncertain. Here we show that the relative concentrations of metal atoms in the upper mesosphere, and the surface accretion rate of cosmic spherules, provide sensitive probes of this distribution. Three cosmic dust models are selected as case studies: two are astronomical models, the first constrained by infrared observations of the Zodiacal Dust Cloud and the second by radar observations of meteor head echoes; the third model is based on measurements made with a spaceborne dust detector. For each model, a Monte Carlo sampling method combined with a chemical ablation model is used to predict the ablation rates of Na, K, Fe, Mg, and Ca above 60 km and cosmic spherule production rate. It appears that a significant fraction of the cosmic dust consists of small (<5 µg) and slow (<15 km s-1) particles.

KEYWORDS:

comets; cosmic dust; cosmic spherules; mesospheric metals; meteor radar; meteoric ablation

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