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Ice iron/sodium film as cause for high noctilucent cloud radar reflectivity

Bellan, P. M. (2008) Ice iron/sodium film as cause for high noctilucent cloud radar reflectivity. Journal of Geophysical Research D, 113 . Art. No. D16215. ISSN 0148-0227. doi:10.1029/2008JD009927.

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Noctilucent clouds, tiny cold electrically charged ice grains located at about 85 km altitude, exhibit anomalously high radar reflectivity. It is shown that this observed high radar reflectivity can be explained by assuming the ice grains are coated by a thin metal film; substantial evidence exists indicating that such a film exists and is caused by the deposition of iron and sodium atoms on the ice grain from iron and sodium layers located immediately above the noctilucent cloud layer. The number of conduction electrons in the thin metal film coating an ice grain is very large. When averaged over the volume occupied by a large number of ice grains, the quivering of these metal film electrons provides a much larger contribution to radar reflectivity than does the much smaller number of dusty plasma electrons or electron holes. Using observations indicating that noctilucent clouds are the dominant sink for the summer-time iron and sodium layers, it is shown that a sufficiently thick metal layer should form on a typical ice grain in a few hours to a few days.

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Bellan, P. M.0000-0002-0886-8782
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Additional Information:Copyright 2008 by the American Geophysical Union. Received 6 February 2008; revised 30 April 2008; accepted 12 June 2008; published 26 August 2008.
Subject Keywords:Noctilucent cloud, PMSE, sodium/iron layer
Record Number:CaltechAUTHORS:BELjgrd08
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Official Citation:Bellan, P. M. (2008), Ice iron/sodium film as cause for high noctilucent cloud radar reflectivity, J. Geophys. Res., 113, D16215, doi:10.1029/2008JD009927.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11738
Deposited By: Archive Administrator
Deposited On:22 Sep 2008 19:45
Last Modified:08 Nov 2021 22:02

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