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| Titel |
Thermospheric winds and temperatures above Mawson, Antarctica, observed with an all-sky imaging, Fabry-Perot spectrometer |
| VerfasserIn |
C. Anderson, M. Conde, P. Dyson, T. Davies, M. J. Kosch |
| 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 ; 27, no. 5 ; Nr. 27, no. 5 (2009-05-15), S.2225-2235 |
| Datensatznummer |
250016539
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| Publikation (Nr.) |
 copernicus.org/angeo-27-2225-2009.pdf |
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| Zusammenfassung |
A new all-sky imaging Fabry-Perot spectrometer has been installed at Mawson station
(67°36' S, 62°52' E), Antarctica. This instrument is capable of recording
independent spectra from many tens of locations across the sky simultaneously. Useful operation
began in March 2007, with spectra recorded on a total of 186 nights. Initial analysis has focused
on the large-scale daily and average behavior of winds and temperatures derived from observations
of the 630.0 nm airglow line of atomic oxygen, originating from a broad layer centered around
240 km altitude, in the ionospheric F-region.
The 1993 Horizontal Wind Model (HWM93), NRLMSISE-00 atmospheric model, and the Coupled
Thermosphere/Ionosphere Plasmasphere (CTIP) model were used for comparison. During the
geomagnetically quiet period studied, observed winds and temperatures were generally well modelled,
although temperatures were consistently higher than NRLMSISE-00 predicted, by up to 100 K. CTIP
temperatures better matched our data, particularly later in the night, but predicted zonal winds
which were offset from those observed by 70–180 ms−1 westward. During periods of increased
activity both winds and temperatures showed much greater variability over time-scales of less than
an hour. For the active night presented here, a period of 45 min saw wind speeds decrease by
around 180 ms−1, and temperatures increase by approximately 100 K. Active-period winds were
poorly modelled by HWM93 and CTIP, although observed median temperatures were in better agreement
with NRLMSISE-00 during such periods.
Average behavior was found to be generally consistent with previous studies of thermospheric winds
above Mawson. The collected data set was representative of quiet geomagnetic and solar conditions.
Geographic eastward winds in the afternoon/evening generally continued until around local
midnight, when winds turned equatorward. Geographic meridional and zonal winds in the afternoon
were approximately 50 ms−1 weaker than expected from HWM93, as was the transition to
equatorward flow around midnight. There was also a negligible geographic zonal component to the
post-midnight wind where HWM93 predicted strong westward flow. Average temperatures between 19:00
and 04:00 local solar time were around 60 K higher than predicted by NRLMSISE-00. |
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