Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx)
From September to November 2005, the NASA Living with a Star program supported the Spread-F Experiment campaign (SpreadFEx) in Brazil to study the effects of convectively generated gravity waves on the ionosphere and their role in seeding Rayleigh-Taylor instabilities, and associated equatorial...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2009-06-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/27/2371/2009/angeo-27-2371-2009.pdf |
| _version_ | 1818924516725751808 |
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| author | P.-D. Pautet M. J. Taylor N. P. Chapagain H. Takahashi A. F. Medeiros F. T. São Sabbas D. C. Fritts |
| author_facet | P.-D. Pautet M. J. Taylor N. P. Chapagain H. Takahashi A. F. Medeiros F. T. São Sabbas D. C. Fritts |
| author_sort | P.-D. Pautet |
| collection | DOAJ |
| description | From September to November 2005, the NASA Living with a Star program
supported the Spread-F Experiment campaign (SpreadFEx) in Brazil to study
the effects of convectively generated gravity waves on the ionosphere and
their role in seeding Rayleigh-Taylor instabilities, and associated
equatorial plasma bubbles. Several US and Brazilian institutes deployed a
broad range of instruments (all-sky imagers, digisondes, photometers,
meteor/VHF radars, GPS receivers) covering a large area of Brazil. The
campaign was divided in two observational phases centered on the September
and October new moon periods. During these periods, an Utah State University
(USU) all-sky CCD imager operated at São João d'Aliança (14.8° S,
47.6° W), near Brasilia, and a Brazilian all-sky CCD imager located
at Cariri (7.4° S, 36° W), observed simultaneously the evolution of
the ionospheric bubbles in the OI (630 nm) emission and the mesospheric
gravity wave field. The two sites had approximately the same magnetic
latitude (9–10° S) but were separated in longitude by ~1500 km.
<br><br>
Plasma bubbles were observed on every clear night (17 from Brasilia and 19
from Cariri, with 8 coincident nights). These joint datasets provided
important information for characterizing the ionospheric depletions during
the campaign and to perform a novel longitudinal investigation of their
variability. Measurements of the drift velocities at both sites are in good
agreement with previous studies, however, the overlapping fields of view
revealed significant differences in the occurrence and structure of the
plasma bubbles, providing new evidence for localized generation. This paper
summarizes the observed bubble characteristics important for related
investigations of their seeding mechanisms associated with gravity wave
activity. |
| first_indexed | 2024-12-20T02:26:35Z |
| format | Article |
| id | doaj.art-34d5c563661a473cb1a25fe0e641d45c |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-20T02:26:35Z |
| publishDate | 2009-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-34d5c563661a473cb1a25fe0e641d45c2022-12-21T19:56:41ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762009-06-01272371238110.5194/angeo-27-2371-2009Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx)P.-D. Pautet0M. J. Taylor1N. P. Chapagain2H. Takahashi3A. F. Medeiros4F. T. São Sabbas5D. C. Fritts6Center for Atmospheric and Space Sciences, Utah State University, Logan, UT, USACenter for Atmospheric and Space Sciences, Utah State University, Logan, UT, USACenter for Atmospheric and Space Sciences, Utah State University, Logan, UT, USAInstituto Nacional de Pesquisas Espaciais (INPE), São José dos Campos, São Paulo, BrazilUniversidade Federal de Campina Grande, Campina Grande, Paraiba, BrazilInstituto Nacional de Pesquisas Espaciais (INPE), São José dos Campos, São Paulo, BrazilNorthWest Research Associates, CoRA Division, Boulder, CO, USAFrom September to November 2005, the NASA Living with a Star program supported the Spread-F Experiment campaign (SpreadFEx) in Brazil to study the effects of convectively generated gravity waves on the ionosphere and their role in seeding Rayleigh-Taylor instabilities, and associated equatorial plasma bubbles. Several US and Brazilian institutes deployed a broad range of instruments (all-sky imagers, digisondes, photometers, meteor/VHF radars, GPS receivers) covering a large area of Brazil. The campaign was divided in two observational phases centered on the September and October new moon periods. During these periods, an Utah State University (USU) all-sky CCD imager operated at São João d'Aliança (14.8° S, 47.6° W), near Brasilia, and a Brazilian all-sky CCD imager located at Cariri (7.4° S, 36° W), observed simultaneously the evolution of the ionospheric bubbles in the OI (630 nm) emission and the mesospheric gravity wave field. The two sites had approximately the same magnetic latitude (9–10° S) but were separated in longitude by ~1500 km. <br><br> Plasma bubbles were observed on every clear night (17 from Brasilia and 19 from Cariri, with 8 coincident nights). These joint datasets provided important information for characterizing the ionospheric depletions during the campaign and to perform a novel longitudinal investigation of their variability. Measurements of the drift velocities at both sites are in good agreement with previous studies, however, the overlapping fields of view revealed significant differences in the occurrence and structure of the plasma bubbles, providing new evidence for localized generation. This paper summarizes the observed bubble characteristics important for related investigations of their seeding mechanisms associated with gravity wave activity.https://www.ann-geophys.net/27/2371/2009/angeo-27-2371-2009.pdf |
| spellingShingle | P.-D. Pautet M. J. Taylor N. P. Chapagain H. Takahashi A. F. Medeiros F. T. São Sabbas D. C. Fritts Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx) Annales Geophysicae |
| title | Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx) |
| title_full | Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx) |
| title_fullStr | Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx) |
| title_full_unstemmed | Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx) |
| title_short | Simultaneous observations of equatorial F-region plasma depletions over Brazil during the Spread-F Experiment (SpreadFEx) |
| title_sort | simultaneous observations of equatorial f region plasma depletions over brazil during the spread f experiment spreadfex |
| url | https://www.ann-geophys.net/27/2371/2009/angeo-27-2371-2009.pdf |
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