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Titel |
Global variation in the long-term seasonal changes observed in ionospheric F region data |
VerfasserIn |
C. J. Scott, R. Stamper |
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. 4 ; Nr. 33, no. 4 (2015-04-08), S.449-455 |
Datensatznummer |
250121187
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Publikation (Nr.) |
copernicus.org/angeo-33-449-2015.pdf |
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Zusammenfassung |
Long-term variability has previously been observed in the relative magnitude
of annual and semi-annual variations in the critical frequency (related to
the peak electron concentration) of the ionospheric F2 layer (foF2). In this
paper we investigate the global patterns in such variability by calculating
the time varying power ratio of semi-annual to annual components seen in
ionospheric foF2 data sequences from 77 ionospheric monitoring stations
around the world. The temporal variation in power ratios observed at each
station was then correlated with the same parameter calculated from similar
epochs for the Slough/Chilton data set (for which there exists the longest
continuous sequence of ionospheric data). This technique reveals strong
regional variation in the data, which bears a striking similarity to the
regional variation observed in long-term changes to the height of the
ionospheric F2 layer. We argue that since both the height and peak density
of the ionospheric F2 region are influenced by changes to thermospheric
circulation and composition, the observed long-term and regional
variability can be explained by such changes. In the absence of long-term
measurements of thermospheric composition, detailed modelling work is
required to investigate these processes. |
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