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| Titel |
Quantitative relation between PMSE and ice mass density |
| VerfasserIn |
S. Kirkwood  , M. Hervig, E. Belova, A. Osepian |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 28, no. 6 ; Nr. 28, no. 6 (2010-06-23), S.1333-1343 |
| Datensatznummer |
250016849
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| Publikation (Nr.) |
 copernicus.org/angeo-28-1333-2010.pdf |
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| Zusammenfassung |
| Radar reflectivities associated with Polar Mesosphere Summer Echoes (PMSE)
are compared with measurements of ice mass density in the mesopause region.
The 54.5 MHz radar Moveable Atmospheric Radar for Antarctica (MARA), located
at the Wasa/Aboa station in Antarctica (73° S, 13° W) provided
PMSE measurements in December 2007 and January 2008. Ice mass density was
measured by the Solar Occultation for Ice Experiment (SOFIE). The radar
operated continuously during this period but only measurements close to local
midnight are used for comparison, to coincide with the local time of the
measurements of ice mass density. The radar location is at high geographic
latitude but low geomagnetic latitude (61°) and the measurements were
made during a period of very low solar activity. As a result, background
electron densities can be modelled based on solar illumination alone. We find
a close correlation between the time and height variations of radar
reflectivity and ice mass density, at all PMSE heights, from 80 km up to 95 km.
A quantitative expression relating radar reflectivities to ice mass
density is found, including an empirical dependence on background electron
density. Using this relation, we can use PMSE reflectivities as a proxy for
ice mass density, and estimate the daily variation of ice mass density from
the daily variation of PMSE reflectivities. According to this proxy, ice mass
density is maximum around 05:00–07:00 LT, with lower values around local noon, in
the afternoon and in the evening. This is consistent with the small number of
previously published measurements and model predictions of the daily
variation of noctilucent (mesospheric) clouds and in contrast to the daily
variation of PMSE, which has a broad daytime maximum, extending from 05:00 LT to
15:00 LT, and an evening-midnight minimum. |
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