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| Titel |
Accuracy issues of the existing thermospheric wind models: can we rely on them in seeking solutions to wind-driven problems? |
| VerfasserIn |
M. F. Larsen, C. G. Fesen |
| 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. 6 ; Nr. 27, no. 6 (2009-06-08), S.2277-2284 |
| Datensatznummer |
250016543
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| Publikation (Nr.) |
 copernicus.org/angeo-27-2277-2009.pdf |
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| Zusammenfassung |
| We address the question of the ability of empirical and general circulation
model neutral wind profiles in the lower thermosphere to reproduce the
observed characteristics of the winds in that part of the atmosphere. The
winds in that altitude range are critical for electrodynamic processes, but
evaluations of the model winds are generally difficult because of the sparse
observational data, which makes an evaluation of the wind predictions over
large areas difficult or impossible. In this paper, we use a recently
identified characteristic of the winds in the lower thermosphere, namely the
enhanced winds and strong shears between 95 and 115 km altitude, as a test of
the models, at least in a statistical sense. Our results show that the
Horizontal Wind Model (HWM) significantly underestimates the maximum winds
and shears in the lower thermosphere, although it has reasonable agreement
with the average winds. The NCAR general circulation model used in this study
also underestimates the maximum winds and shears significantly when run with
standard resolution, as well as producing an unrealistic increase of the wind
speed with height. The agreement between the model and the observations
improves significantly however, in a statistical sense, when the altitude
resolution is increased. The improved height resolution in the model appears
to produce a greater improvement in the model predictions than any of the
other factors that we examined, such as improving the geomagnetic forcing or
the forcing at the lower boundary. |
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