Equatorial plasma bubbles in the ionosphere over Eritrea: occurrence and drift speed

Autor: R. H. Wiens, M. Afewerki, Brent M. Ledvina, Z. Mulugheta, Paul M. Kintner
Přispěvatelé: EGU, Publication, Computer Systems Lab - School of Electrical and Computer Engineering - Cornell University (CSL), Cornell University [New York], Department of Physics, Okayama University
Rok vydání: 2006
Předmět:
Magnetic declination
Atmospheric Science
Drift velocity
010504 meteorology & atmospheric sciences
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Atmospheric sciences
01 natural sciences
0103 physical sciences
Earth and Planetary Sciences (miscellaneous)
lcsh:Science
010303 astronomy & astrophysics
0105 earth and related environmental sciences
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean
Atmosphere
Scintillation
[SDU.OCEAN] Sciences of the Universe [physics]/Ocean
Atmosphere
business.industry
Anomaly (natural sciences)
lcsh:QC801-809
Airglow
Geology
Astronomy and Astrophysics
lcsh:QC1-999
lcsh:Geophysics. Cosmic physics
13. Climate action
Space and Planetary Science
Physics::Space Physics
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences
Global Positioning System
lcsh:Q
Ionosphere
business
Longitude
lcsh:Physics
Zdroj: Annales Geophysicae, Vol 24, Iss 5, Pp 1443-1453 (2006)
Annales Geophysicae, Vol 24, Pp 1443-1453 (2006)
Annales Geophysicae
Annales Geophysicae, European Geosciences Union, 2006, 24 (5), pp.1443-1453
ISSN: 1432-0576
0992-7689
DOI: 10.5194/angeo-24-1443-2006
Popis: 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.
Databáze: OpenAIRE
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