Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes
The signature of the stable auroral red arc (SAR arc) as it appears on ionograms is described. The key features are a very significant increase in the amount of spread-F and a reduction in the maximum plasma density compared with regions just equatorward and poleward of the SAR arc Identification of...
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ftnerc:oai:nora.nerc.ac.uk:523587 2023-05-15T13:41:43+02:00 Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes Rodger, Alan S. 1984 http://nora.nerc.ac.uk/id/eprint/523587/ https://doi.org/10.1016/0021-9169(84)90117-X unknown Elsevier Rodger, Alan S. 1984 Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes. Journal of Atmospheric and Terrestrial Physics, 46 (4). 335-342. https://doi.org/10.1016/0021-9169(84)90117-X <https://doi.org/10.1016/0021-9169(84)90117-X> Publication - Article PeerReviewed 1984 ftnerc https://doi.org/10.1016/0021-9169(84)90117-X 2023-02-04T19:48:28Z The signature of the stable auroral red arc (SAR arc) as it appears on ionograms is described. The key features are a very significant increase in the amount of spread-F and a reduction in the maximum plasma density compared with regions just equatorward and poleward of the SAR arc Identification of the SAR arc signature is made by using complementary data from the global auroral imaging instrument on board the Dynamics Explorer-1 satellite. At sunspot minimum there is a positive correlation between the occurrence of spread-F on ionograms from Argentine Islands, Antarctica (65°S, 64°W; L = 2.3) and magnetic activity. In contrast, at sunspot maximum there is a weak negative correlation when the K magnetic index is less than 6. but a significant increase in spread-F occurrence at K ⩾ 6. Detailed study of ionograms shows that there are two distinct regions where considerable spread-F is observed. These are the region where SAR arcs occur and the poleward edge of the mid-latitude ionospheric trough. They are separated by a region associated with the trough minimum, where comparatively little spread-F is seen. It is suggested that the movement of these features to lower latitudes with increasing magnetic and solar activity can explain the lack of correspondence between variations of spread-F occurrence as a function of magnetic activity at sunspot maximum compared with that at sunspot minimum at Argentine Islands. Article in Journal/Newspaper Antarc* Antarctica Argentine Islands Natural Environment Research Council: NERC Open Research Archive Argentine Argentine Islands ENVELOPE(-64.273,-64.273,-65.246,-65.246) Journal of Atmospheric and Terrestrial Physics 46 4 335 342 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
language |
unknown |
description |
The signature of the stable auroral red arc (SAR arc) as it appears on ionograms is described. The key features are a very significant increase in the amount of spread-F and a reduction in the maximum plasma density compared with regions just equatorward and poleward of the SAR arc Identification of the SAR arc signature is made by using complementary data from the global auroral imaging instrument on board the Dynamics Explorer-1 satellite. At sunspot minimum there is a positive correlation between the occurrence of spread-F on ionograms from Argentine Islands, Antarctica (65°S, 64°W; L = 2.3) and magnetic activity. In contrast, at sunspot maximum there is a weak negative correlation when the K magnetic index is less than 6. but a significant increase in spread-F occurrence at K ⩾ 6. Detailed study of ionograms shows that there are two distinct regions where considerable spread-F is observed. These are the region where SAR arcs occur and the poleward edge of the mid-latitude ionospheric trough. They are separated by a region associated with the trough minimum, where comparatively little spread-F is seen. It is suggested that the movement of these features to lower latitudes with increasing magnetic and solar activity can explain the lack of correspondence between variations of spread-F occurrence as a function of magnetic activity at sunspot maximum compared with that at sunspot minimum at Argentine Islands. |
format |
Article in Journal/Newspaper |
author |
Rodger, Alan S. |
spellingShingle |
Rodger, Alan S. Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes |
author_facet |
Rodger, Alan S. |
author_sort |
Rodger, Alan S. |
title |
Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes |
title_short |
Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes |
title_full |
Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes |
title_fullStr |
Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes |
title_full_unstemmed |
Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes |
title_sort |
spread-f ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes |
publisher |
Elsevier |
publishDate |
1984 |
url |
http://nora.nerc.ac.uk/id/eprint/523587/ https://doi.org/10.1016/0021-9169(84)90117-X |
long_lat |
ENVELOPE(-64.273,-64.273,-65.246,-65.246) |
geographic |
Argentine Argentine Islands |
geographic_facet |
Argentine Argentine Islands |
genre |
Antarc* Antarctica Argentine Islands |
genre_facet |
Antarc* Antarctica Argentine Islands |
op_relation |
Rodger, Alan S. 1984 Spread-F ionospheric irregularities and their relationship to stable auroral red arcs at magnetic mid-latitudes. Journal of Atmospheric and Terrestrial Physics, 46 (4). 335-342. https://doi.org/10.1016/0021-9169(84)90117-X <https://doi.org/10.1016/0021-9169(84)90117-X> |
op_doi |
https://doi.org/10.1016/0021-9169(84)90117-X |
container_title |
Journal of Atmospheric and Terrestrial Physics |
container_volume |
46 |
container_issue |
4 |
container_start_page |
335 |
op_container_end_page |
342 |
_version_ |
1766155124595490816 |