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| Titel |
Absolute density measurements in the middle atmosphere |
| VerfasserIn |
M. Rapp, J. Gumbel, F.-J. Lübken |
| 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 ; 19, no. 5 ; Nr. 19, no. 5, S.571-580 |
| Datensatznummer |
250014255
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| Publikation (Nr.) |
 copernicus.org/angeo-19-571-2001.pdf |
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| Zusammenfassung |
In the last ten years a
total of 25 sounding rockets employing ionization gauges have been launched at
high latitudes ( ~ 70° N) to measure total atmospheric density and its small
scale fluctuations in an altitude range between 70 and 110 km. While the
determination of small scale fluctuations is unambiguous, the total density
analysis has been complicated in the past by aerodynamical disturbances leading
to densities inside the sensor which are enhanced compared to atmospheric
values. Here, we present the results of both Monte Carlo simulations and wind
tunnel measurements to quantify this aerodynamical effect. The comparison of
the resulting ‘ram-factor’ profiles with empirically determined density
ratios of ionization gauge measurements and falling sphere measurements
provides excellent agreement. This demonstrates both the need, but also the
possibility, to correct aerodynamical influences on measurements from sounding
rockets. We have determined a total of 20 density profiles of the
mesosphere-lower-thermosphere (MLT) region. Grouping these profiles according
to season, a listing of mean density profiles is included in the paper. A
comparison with density profiles taken from the reference atmospheres CIRA86
and MSIS90 results in differences of up to 40%. This reflects that current
reference atmospheres are a significant potential error source for the
determination of mixing ratios of, for example, trace gas constituents in the
MLT region.
Key words. Middle atmosphere
(composition and chemistry; pressure, density, and temperature; instruments and
techniques) |
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