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| Titel |
Empirical regional models for the short-term forecast of M3000F2 during not quiet geomagnetic conditions over Europe |
| VerfasserIn |
M. Pietrella |
| 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. 10 ; Nr. 31, no. 10 (2013-10-07), S.1653-1671 |
| Datensatznummer |
250086118
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| Publikation (Nr.) |
 copernicus.org/angeo-31-1653-2013.pdf |
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| Zusammenfassung |
Twelve empirical local models have been developed for the long-term prediction
of the ionospheric characteristic M3000F2, and then used as starting point for the
development of a short-term forecasting empirical regional model of
M3000F2 under not quiet geomagnetic conditions. Under the assumption that the
monthly median measurements of M3000F2 are linearly correlated to the solar
activity, a set of regression coefficients were calculated over 12 months
and 24 h for each of 12 ionospheric observatories located in the
European area, and then used for the long-term prediction of M3000F2 at each
station under consideration.
Based on the 12 long-term prediction empirical local models of M3000F2, an empirical
regional model for the prediction of the monthly median field of M3000F2 over Europe
(indicated as RM_M3000F2) was developed.
Thanks to the IFELM_foF2 models, which are able to provide short-term forecasts of the
critical frequency of the F2 layer (foF2STF) up to three hours in advance,
it was possible to considerer the Brudley–Dudeney algorithm as a function of
foF2STF to correct RM_M3000F2 and thus obtain an empirical regional model
for the short-term forecasting of M3000F2 (indicated as RM_M3000F2_BD) up to three hours in
advance under not quiet geomagnetic conditions.
From the long-term predictions of M3000F2 provided by the IRI model, an empirical
regional model for the forecast of the monthly median field of M3000F2 over Europe
(indicated as IRI_RM_M3000F2) was derived.
IRI_RM_M3000F2 predictions were modified with the Bradley–Dudeney correction factor, and
another empirical regional model for the short-term forecasting of M3000F2
(indicated as IRI_RM_M3000F2_BD) up to three hours ahead under not quiet geomagnetic
conditions was obtained.
The main results achieved comparing the performance of RM_M3000F2, RM_M3000F2_BD, IRI_RM_M3000F2, and
IRI_RM_M3000F2_BD are (1) in the case of moderate geomagnetic activity, the Bradley–Dudeney
correction factor does not improve significantly the predictions; (2) under
disturbed geomagnetic conditions, the Bradley–Dudeney formula improves the
predictions of RM_M3000F2 in the entire European area; (3) in the case of very disturbed
geomagnetic conditions, the Bradley–Dudeney algorithm is very effective in
improving the performance of IRI_RM_M3000F2; (4) under moderate geomagnetic conditions,
the long-term prediction maps of M3000F2 generated by RM_M3000F2 can be considered as
short-term forecasting maps providing very satisfactory results because
quiet geomagnetic conditions are not so diverse from moderate geomagnetic
conditions; (5) the forecasting maps originated by RM_M3000F2, RM_M3000F2_BD,
and IRI_RM_M3000F2_BD show some regions
where the forecasts are not satisfactory, but also wide sectors where the
M3000F2 forecasts quite faithfully match the M3000F2 observations, and therefore
RM_M3000F2, RM_M3000F2_BD, and IRI_RM_M3000F2_BD
could be exploited to produce short-term forecasting maps of M3000F2 over
Europe up to 3 h in advance. |
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