Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed
An all-sky imager was installed in Asmara, Eritrea (15.4° N, 38.9° E, 7° N dip) and used to monitor the OI 630-nm nightglow. Nine months of data were studied between September 2001 and May 2002, a time including the recent maximum in the solar activity cycle. Equatorial p...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2006-07-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/24/1443/2006/angeo-24-1443-2006.pdf |
| _version_ | 1811268824376279040 |
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| author | R. H. Wiens B. M. Ledvina B. M. Ledvina P. M. Kintner M. Afewerki Z. Mulugheta |
| author_facet | R. H. Wiens B. M. Ledvina B. M. Ledvina P. M. Kintner M. Afewerki Z. Mulugheta |
| author_sort | R. H. Wiens |
| collection | DOAJ |
| description | An all-sky imager was installed in Asmara, Eritrea (15.4° N,
38.9° E, 7° N dip) and used to monitor the OI 630-nm
nightglow. Nine months of data were studied between September 2001
and May 2002, a time including the recent maximum in the solar
activity cycle. Equatorial plasma bubbles (EPBs) were recorded on
63% of nights with adequate viewing conditions. The station
location within view of the equatorial ionization anomaly and with
a magnetic declination near zero makes it an excellent test case
for comparison with satellite studies of the seasonal variation of EPBs with longitude.
The imager was accompanied by two
Cornell GPS scintillation monitors, and the amplitude
scintillation data are compared to the all-sky data. GPS
scintillations indicate the beginning of EPBs, but die out sooner
in the post-midnight period than the larger scale EPBs. Both
phenomena exhibit clear occurrence maxima around the equinoxes.
Ionospheric zonal drift speeds have been deduced from EPB and GPS
scintillation pattern movement. Average near-midnight EPB drift
speeds are between 100 and 120 m/s most months, with the GPS
scintillation speeds being about the same. A winter drift speed
maximum is evident in both EPB and GPS scintillation monthly
means. |
| first_indexed | 2024-04-12T21:29:52Z |
| format | Article |
| id | doaj.art-2426fb8843504e68af406e74aaad57d3 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-04-12T21:29:52Z |
| publishDate | 2006-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-2426fb8843504e68af406e74aaad57d32022-12-22T03:16:03ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762006-07-01241443145310.5194/angeo-24-1443-2006Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speedR. H. Wiens0B. M. Ledvina1B. M. Ledvina2P. M. Kintner3M. Afewerki4Z. Mulugheta5School of Electrical and Computer Engineering, Cornell University, Ithaca, New York, USASchool of Electrical and Computer Engineering, Cornell University, Ithaca, New York, USAnow at: Applied Research Laboratories, University of Texas at Austin, USASchool of Electrical and Computer Engineering, Cornell University, Ithaca, New York, USADepartment of Physics, University of Asmara, Asmara, EritreaDepartment of Physics, University of Asmara, Asmara, EritreaAn all-sky imager was installed in Asmara, Eritrea (15.4° N, 38.9° E, 7° N dip) and used to monitor the OI 630-nm nightglow. Nine months of data were studied between September 2001 and May 2002, a time including the recent maximum in the solar activity cycle. Equatorial plasma bubbles (EPBs) were recorded on 63% of nights with adequate viewing conditions. The station location within view of the equatorial ionization anomaly and with a magnetic declination near zero makes it an excellent test case for comparison with satellite studies of the seasonal variation of EPBs with longitude. The imager was accompanied by two Cornell GPS scintillation monitors, and the amplitude scintillation data are compared to the all-sky data. GPS scintillations indicate the beginning of EPBs, but die out sooner in the post-midnight period than the larger scale EPBs. Both phenomena exhibit clear occurrence maxima around the equinoxes. Ionospheric zonal drift speeds have been deduced from EPB and GPS scintillation pattern movement. Average near-midnight EPB drift speeds are between 100 and 120 m/s most months, with the GPS scintillation speeds being about the same. A winter drift speed maximum is evident in both EPB and GPS scintillation monthly means.https://www.ann-geophys.net/24/1443/2006/angeo-24-1443-2006.pdf |
| spellingShingle | R. H. Wiens B. M. Ledvina B. M. Ledvina P. M. Kintner M. Afewerki Z. Mulugheta Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed Annales Geophysicae |
| title | Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed |
| title_full | Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed |
| title_fullStr | Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed |
| title_full_unstemmed | Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed |
| title_short | Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed |
| title_sort | equatorial plasma bubbles in the ionosphere over eritrea occurrence and drift speed |
| url | https://www.ann-geophys.net/24/1443/2006/angeo-24-1443-2006.pdf |
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