Non-trough <i>fo</i>F2 enhancements at near-equatorial dip latitudes
Fine resolution series from three equatorial ionosondes of the IEEY network in West Africa have revealed small-scale daytime peak F2 structures, superposed on the slowly varying minimum or "trough" distribution in the ±5° magnetic latitude zone. We report this new morphology, concentra...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
1998-06-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/16/711/1998/angeo-16-711-1998.pdf |
| _version_ | 1818961233966006272 |
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| author | E. Sambou P. M. Vila A. T. Kobea |
| author_facet | E. Sambou P. M. Vila A. T. Kobea |
| author_sort | E. Sambou |
| collection | DOAJ |
| description | Fine resolution series from three equatorial
ionosondes of the IEEY network in West Africa have revealed small-scale daytime
peak F2 structures, superposed on the slowly varying minimum or
"trough" distribution in the ±5° magnetic latitude zone. We report
this new morphology, concentrating on <i>f</i>oF2 enhancements of two types:
near-equatorial crests (which travel either northwards or southwards) and
magnetic field-aligned domes, whose onsets last only tens of minutes. Both types
are observed to start at mid-morning or early afternoon hours. We relate their
occurrence with the available variations of <b>Vz</b>=<b>E </b>×<b> B</b>
upward drift which feeds the equatorial plasma fountain. We suggest the <i>f</i>oF2
enhancements to be triggered by brief slow-downs of the <b>Vz</b> velocity near
F2 peak altitude in our West African sector. Their short latitude extent
differentiates them from the larger-scale tropical crest system. Further
analysis of these features should lead to weather-like models of the low
latitude ionosphere variations, where unstable local coupling between processes
seems to be the trigger.<br><br><b>Key words. </b>Ionosphere (Equatorial ionosphere ·
Ionosphere-atmosphere interaction · Plasma temperature and density)</p> |
| first_indexed | 2024-12-20T12:10:11Z |
| format | Article |
| id | doaj.art-fd3844524e77412497132b265f1d3557 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-20T12:10:11Z |
| publishDate | 1998-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-fd3844524e77412497132b265f1d35572022-12-21T19:41:16ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05761998-06-011671172010.1007/s00585-998-0711-8Non-trough <i>fo</i>F2 enhancements at near-equatorial dip latitudesE. Sambou0P. M. Vila1A. T. Kobea2Département de Physique, Université C. Anta Diop, Dakar-Fann, SenegalCentre d'Étude des Environnements Terrestres et Planétaires (CETP), 4 Avenue de Neptune, F-94107, Saint-Maur-des-Fossés, FranceDépartement de Physique de l'Atmosphère, Université de Cocody, 22 BP582, Abidjan 22, Côte d'IvoireFine resolution series from three equatorial ionosondes of the IEEY network in West Africa have revealed small-scale daytime peak F2 structures, superposed on the slowly varying minimum or "trough" distribution in the ±5° magnetic latitude zone. We report this new morphology, concentrating on <i>f</i>oF2 enhancements of two types: near-equatorial crests (which travel either northwards or southwards) and magnetic field-aligned domes, whose onsets last only tens of minutes. Both types are observed to start at mid-morning or early afternoon hours. We relate their occurrence with the available variations of <b>Vz</b>=<b>E </b>×<b> B</b> upward drift which feeds the equatorial plasma fountain. We suggest the <i>f</i>oF2 enhancements to be triggered by brief slow-downs of the <b>Vz</b> velocity near F2 peak altitude in our West African sector. Their short latitude extent differentiates them from the larger-scale tropical crest system. Further analysis of these features should lead to weather-like models of the low latitude ionosphere variations, where unstable local coupling between processes seems to be the trigger.<br><br><b>Key words. </b>Ionosphere (Equatorial ionosphere · Ionosphere-atmosphere interaction · Plasma temperature and density)</p>https://www.ann-geophys.net/16/711/1998/angeo-16-711-1998.pdf |
| spellingShingle | E. Sambou P. M. Vila A. T. Kobea Non-trough <i>fo</i>F2 enhancements at near-equatorial dip latitudes Annales Geophysicae |
| title | Non-trough <i>fo</i>F2 enhancements at near-equatorial dip latitudes |
| title_full | Non-trough <i>fo</i>F2 enhancements at near-equatorial dip latitudes |
| title_fullStr | Non-trough <i>fo</i>F2 enhancements at near-equatorial dip latitudes |
| title_full_unstemmed | Non-trough <i>fo</i>F2 enhancements at near-equatorial dip latitudes |
| title_short | Non-trough <i>fo</i>F2 enhancements at near-equatorial dip latitudes |
| title_sort | non trough i fo i f2 enhancements at near equatorial dip latitudes |
| url | https://www.ann-geophys.net/16/711/1998/angeo-16-711-1998.pdf |
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