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| Titel |
Mass Influx of Cosmic Dust Estimated From Vertical Transport of Meteoric Metals |
| VerfasserIn |
Alan Z. Liu, Yafang Guo, Chester S. Gardner |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123031
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| Publikation (Nr.) |
 EGU/EGU2016-2200.pdf |
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| Zusammenfassung |
| The mesospheric metal layers are formed by the vaporization of high-speed cosmic dust
particles in the lower thermosphere and upper mesosphere. The vaporized atoms and ions are
transported downward by waves and turbulence to chemical sinks below 85 km, where
they form stable compounds. These compounds condense onto meteoric smoke
particles and are then transported to the winter pole where they eventually settle
onto the surface. The downward fluxes of the metal atoms are directly related to
their meteoric influxes and chemical loss rates. In this paper we use Doppler lidar
measurements of Na and Fe fluxes made by the University of Illinois and University of
Colorado groups, and a chemical ablation model (CABMOD) developed at the
University of Leeds, to constrain the velocity/mass distribution of the meteoroids
entering the atmosphere and to derive an improved estimate for the global influx of
cosmic dust. We find that the particles responsible for injecting a large fraction of the
ablated material into the Earth’s upper atmosphere, enter at relatively slow speeds and
originate primarily from the Jupiter Family of Comets. The global mean Na influx is
21,500±1,100 atoms/cm2/s, which equals 372±18 kg/d for the global input of Na vapor
and 186±24 t/d for the global influx of cosmic dust. The global mean Fe influx is
131,000±36,000 atoms/cm2/s, which equals 5.5±1.5 t/d for the global input of Na
vapor. |
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