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| Titel |
Medium-scale 4-D ionospheric tomography using a dense GPS network |
| VerfasserIn |
M. M. J. L. Kamp |
| 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. 1 ; Nr. 31, no. 1 (2013-01-10), S.75-89 |
| Datensatznummer |
250017739
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| Publikation (Nr.) |
 copernicus.org/angeo-31-75-2013.pdf |
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| Zusammenfassung |
The ionosphere above Scandinavia in December 2006 is successfully imaged by
4-dimensional tomography using the software package MIDAS from the
University of Bath. The method concentrates on medium-scale structures:
between 100 km and 2000 km in horizontal size. The input consists of TEC
measurements from the dense GPS network Geotrim in Finland. In order to
ensure sufficient vertical resolution of the result, EISCAT incoherent
scatter radar data from Tromsø are used as additional input to provide
the vertical profile information.
The TEC offset of the measurements is unknown, but the inversion procedure is
able to determine this automatically. This auto-calibration is shown to work
well.
Comparisons with EISCAT radar results and with occultation results show that
the inversion using EISCAT data for profile information is much better able
to resolve vertical profiles of irregular structures than the inversion
using built-in profiles. Still, with either method the intensities of
irregular structures of sizes near the resolution (about 100 km horizontal size) can be underestimated. Also, the accuracy of
the inversion worsens above areas where no receivers are available.
The ionosphere over Scandinavia in December 2006 often showed a dense
E-layer in early morning hours, which generally disappeared during midday
when a dense F-layer was present. On 14 December, a strong coronal mass
ejection occurred, and many intense irregularities appeared in the
ionosphere, which extended to high altitudes. |
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