Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic storms
The global evolutions of <i>fo</i>F2 anomalies were examined for three very intense geomagnetic storms, namely the Halloween events of October-November 2003 (Event X, 29–30 October 2003, <i>D<sub>st</sub></i> –401 nT; Event Y, 20–21 November 2003, <i>D<...
| Main Author: | |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2005-10-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/23/2487/2005/angeo-23-2487-2005.pdf |
| _version_ | 1818497342657003520 |
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| author | R. P. Kane |
| author_facet | R. P. Kane |
| author_sort | R. P. Kane |
| collection | DOAJ |
| description | The global evolutions of <i>fo</i>F2 anomalies were examined for
three very intense geomagnetic storms, namely the Halloween events of
October-November 2003 (Event X, 29–30 October 2003, <i>D<sub>st</sub></i> –401 nT; Event Y, 20–21 November
2003, <i>D<sub>st</sub></i> –472 nT), and the largest <i>D<sub>st</sub></i> storm (Event Z, 13–14 March 1989, <i>D<sub>st</sub></i> –589 nT).
For Event X, troughs (negative storms) were clearly seen
for high northern and southern latitudes. For northern midlatitudes as well
as for low latitudes, there were very strong positive effects on 29 October 2003,
followed by negative effects the next day. For Event Y, there were no troughs in
NH high latitudes for morning and evening hours but there were troughs for
night. For midlatitudes and low latitudes, some longitudes showed strong
negative effects in the early morning as expected, but some longitudes showed
strong positive effects at noon and in the evening hours. Thus, there were
many deviations from the model patterns. The deviations were erratic,
indicating considerable local effects superposed on general patterns. A
disconcerting feature was the presence of strong positive effects
during the 24 h before the storm commencement. Such a
feature appears only in the 24 h before the geomagnetic storm
commencement but not earlier. If genuine, these could imply a prediction
potential with a 24-h antecedence. For Event Z (13–14 March 1989,
equinox), all stations (all latitudes and longitudes) showed a very strong
"negative storm" in the main phase, and no positive storms anywhere.<br><br>
<b>Keywords.</b> Ionosphere (Equatorial ionosphere – Ionospheric
disturbances – Mid-latitude Ionosphere – Polar ionosphere) |
| first_indexed | 2024-12-10T18:44:27Z |
| format | Article |
| id | doaj.art-456bf207aa034949a4e8bd640c4a59a9 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-10T18:44:27Z |
| publishDate | 2005-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-456bf207aa034949a4e8bd640c4a59a92022-12-22T01:37:33ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762005-10-01232487249910.5194/angeo-23-2487-2005Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic stormsR. P. Kane0Instituto Nacional de Pesquisas Espacias, São Jose dos Campos, São Paulo, BrazilThe global evolutions of <i>fo</i>F2 anomalies were examined for three very intense geomagnetic storms, namely the Halloween events of October-November 2003 (Event X, 29–30 October 2003, <i>D<sub>st</sub></i> –401 nT; Event Y, 20–21 November 2003, <i>D<sub>st</sub></i> –472 nT), and the largest <i>D<sub>st</sub></i> storm (Event Z, 13–14 March 1989, <i>D<sub>st</sub></i> –589 nT). For Event X, troughs (negative storms) were clearly seen for high northern and southern latitudes. For northern midlatitudes as well as for low latitudes, there were very strong positive effects on 29 October 2003, followed by negative effects the next day. For Event Y, there were no troughs in NH high latitudes for morning and evening hours but there were troughs for night. For midlatitudes and low latitudes, some longitudes showed strong negative effects in the early morning as expected, but some longitudes showed strong positive effects at noon and in the evening hours. Thus, there were many deviations from the model patterns. The deviations were erratic, indicating considerable local effects superposed on general patterns. A disconcerting feature was the presence of strong positive effects during the 24 h before the storm commencement. Such a feature appears only in the 24 h before the geomagnetic storm commencement but not earlier. If genuine, these could imply a prediction potential with a 24-h antecedence. For Event Z (13–14 March 1989, equinox), all stations (all latitudes and longitudes) showed a very strong "negative storm" in the main phase, and no positive storms anywhere.<br><br> <b>Keywords.</b> Ionosphere (Equatorial ionosphere – Ionospheric disturbances – Mid-latitude Ionosphere – Polar ionosphere)https://www.ann-geophys.net/23/2487/2005/angeo-23-2487-2005.pdf |
| spellingShingle | R. P. Kane Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic storms Annales Geophysicae |
| title | Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic storms |
| title_full | Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic storms |
| title_fullStr | Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic storms |
| title_full_unstemmed | Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic storms |
| title_short | Ionospheric <i>fo</i>F2 anomalies during some intense geomagnetic storms |
| title_sort | ionospheric i fo i f2 anomalies during some intense geomagnetic storms |
| url | https://www.ann-geophys.net/23/2487/2005/angeo-23-2487-2005.pdf |
| work_keys_str_mv | AT rpkane ionosphericifoif2anomaliesduringsomeintensegeomagneticstorms |