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| Titel |
Polar cap patches observed during the magnetic storm of November 2003: observations and modeling |
| VerfasserIn |
C. E. Valladares, T. Pedersen, R. Sheehan |
| 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 ; 33, no. 9 ; Nr. 33, no. 9 (2015-09-14), S.1117-1133 |
| Datensatznummer |
250121245
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| Publikation (Nr.) |
 copernicus.org/angeo-33-1117-2015.pdf |
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| Zusammenfassung |
| We present multi-instrumented measurements and multi-technique analysis of
polar cap patches observed early during the recovery phase of the major
magnetic storm of 20 November 2003 to investigate the origin of the polar
cap patches. During this event, the Qaanaaq imager observed elongated polar
cap patches, some of which containing variable brightness; the Qaanaaq
digisonde detected abrupt NmF2 fluctuations; the Sondrestrom
incoherent scatter radar (ISR) measured patches placed close to but
poleward of the auroral oval–polar cap boundary; and the DMSP-F13 satellite
intersected topside density enhancements, corroborating the presence of the
patches seen by the imager, the digisonde, and the Sondrestrom ISR. A 2-D
cross-correlation analysis was applied to series of two consecutive red-line
images, indicating that the magnitude and direction of the patch velocities
were in good agreement with the SuperDARN convection patterns. We applied a
back-tracing analysis to the patch locations and found that most of the
patches seen between 20:41 and 21:29 UT were likely transiting the throat
region near 19:41 UT. Inspection of the SuperDARN velocities at this time
indicates spatial and temporal collocation of a gap region between patches
and large (1.7 km s−1) line-of-sight velocities. The variable airglow
brightness of the patches observed between 20:33 and 20:43 UT was investigated
using the numerical Global Theoretical Ionospheric Model (GTIM) driven by
the SuperDARN convection patterns and a variable upward/downward neutral
wind. Our numerical results indicate that variations in the airglow
intensity up to 265 R can be produced by a constant 70 m s−1 downward
vertical wind. |
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