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| Titel |
Exploring the role of ionospheric drivers during the extreme solar minimum of 2008 |
| VerfasserIn |
J. Klenzing, A. G. Burrell, R. A. Heelis, J. D. Huba, R. Pfaff, F. Simões |
| 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 ; 31, no. 12 ; Nr. 31, no. 12 (2013-12-04), S.2147-2156 |
| Datensatznummer |
250086157
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| Publikation (Nr.) |
 copernicus.org/angeo-31-2147-2013.pdf |
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| Zusammenfassung |
| During the recent solar minimum, solar activity reached the lowest levels
observed during the space age, resulting in a contracted atmosphere. This
extremely low solar activity provides an unprecedented opportunity to
understand the variability of the Earth's ambient ionosphere. The average
E × B drifts measured by the Vector Electric Field
Instrument (VEFI) on the Communications/Navigation Outage Forecasting System
(C/NOFS) satellite during this period are found to have several differences
from the expected climatology based on previous solar minima, including
downward drifts in the early afternoon and a weak to non-existent
pre-reversal enhancement. Using SAMI2 (Sami2 is Another Model of the
Ionosphere) as a computational engine, we investigate the effects of these
electrodynamical changes as well as the contraction of the thermosphere and
reduced EUV ionization on the ionosphere. The sensitivity of the simulations
to wind models is also discussed. These modeled ionospheres are compared to
the C/NOFS average topside ion density and composition and Formosa
Satellite-3/Constellation Observing System for Meteorology, Ionosphere, and
Climate average NmF2 and hmF2. In all cases, incorporating
the VEFI drift data significantly improves the model results when compared to
both the C/NOFS density data and the F3/C GOX data. Changing the MSIS and
EUVAC models produced changes in magnitude, but not morphology with respect
to local time. The choice of wind model modulates the resulting topside
density and composition, but only the use of the VEFI E × B drifts produces the observed post-sunset drop in the F peak. |
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