 |
| Titel |
Ionospheric F1 layer long-term trends and the geomagnetic control concept |
| VerfasserIn |
A. V. Mikhailov |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 26, no. 12 ; Nr. 26, no. 12 (2008-11-28), S.3793-3803 |
| Datensatznummer |
250016310
|
| Publikation (Nr.) |
 copernicus.org/angeo-26-3793-2008.pdf |
|
|
|
|
|
| Zusammenfassung |
| A previous approach to the ionospheric long-term trend analysis has
been applied to the foF1 observations from Slough and Rome in order to
investigate a possible relationship between the foF1 and the long-term variation
of geomagnetic activity. A 40-year period, starting in 1962, has been used for
the analysis. According to the results obtained earlier for F2 and E-region
trends, geomagnetic control of the long-term variation has also been
revealed for the foF1. Thus, it is now possible to speak about the geomagnetic
control of the ionospheric trends in the whole ionosphere. This is not
surprising as the Earth's ionosphere is a single entity that is strongly
controlled, either directly or indirectly, by the magnetic field. As with the
F2-region, this geomagnetic control is provided via neutral composition and
temperature changes. A very long-term (centennial) increase in geomagnetic
activity in the 20th century is seen in the long-term foF1 variations
as well. After its removal, the residual foF1 trends are very small and
insignificant. In principal, this means that the observed foF1 long-term variations
have a natural origin and can be attributed to solar and
geomagnetic activity long-term variations. However, the situation in the
thermosphere has been changing since 1997 and available foF2 observations at
the two stations reveal information about the "break down" of the
geomagnetic control in the F2-region. Possible reasons of these changes are
discussed. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|