Longitudinal variation of equatorial electrojet parameters derived from POGO satellite observations

Onwumechili, C. Agodi; Agu, C.E

doi:10.1016/0032-0633(81)90111-2

Cited by 56 publications

(39 citation statements)

References 12 publications

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“…Consequently, it allowed the characterization, on a global scale of the eect of the EEJ from altitudes between 400 and 800 km (Cain and Sweeney, 1973). The analysis of these data demonstrated several global characteristics of the EEJ (Onwumechili and Agu, 1980, 1981a, b, 1982: the EEJ axis is very close to the geomagnetic equator, on a global scale; the EEJ parameters (half width w, peak intensity J 0 , total current I ) change with longitude and local time: w is minimum, and J 0 and I maximum at noon.…”

Section: Spatial Measurementsmentioning

confidence: 98%

Equatorial electrojet at African longitudes: first results from magnetic measurements

Doumouya

Vassal²,

Cohen³

et al. 1998

Ann Geophysicae

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Abstract. In the framework of the French participation in the International Equatorial Electrojet Year (IEEY), ten magnetotelluric stations were installed between November 1992 and November 1994 along a 1200-kmlong meridian pro®le, between Lamto (latitude 6.2°N, CoÃ te d'Ivoire) to the south and Tombouctou (latitude 16.7°N, Mali) to the north. These stations measured digitally the three components of the magnetic ®eld and the two components of the telluric electric ®eld, and operated over a period of 20 months. The magnetic data is used to study the features of the equatorial electrojet (EEJ) in West African longitude. The measurement of the telluric electric ®eld variations will be presented elsewhere. Hourly mean values are used to study the morphological structure of the regular diurnal variation S R of the three components (H, D, and Z) of the earth magnetic ®eld and to characterize the EEJ during magnetically quiet days. The occurrences of the counter-electrojet (CEJ) are set forth, emphasizing its seasonal variability. Assumed to be a current ribbon, the EEJ main parameters (the position of its center, its width, and the amplitude of its current density at the center) are determined. A preliminary analysis of the time variations of these parameters is presented over period of 20 months (from January 1993 to August 1994). Results are compared with those obtained during previous experiments of the same kind.

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Section: Spatial Measurementsmentioning

confidence: 98%

Equatorial electrojet at African longitudes: first results from magnetic measurements

Doumouya

Vassal²,

Cohen³

et al. 1998

Ann Geophysicae

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“…Early satellite observations showed diverse results (Cain and Sweeney 1973;Onwumechili and Agu 1981;Langel et al 1993;Kim and King 1999;Jadhav et al 2002;Ivers et al 2003;Lühr et al 2004). More recent studies have established that the longitudinal variation of the daytime equatorial electrojet intensity is often dominated by the so-called "wave-4" pattern with four peaks and four troughs between 0°and 360°longitudes (Le Mouël et al 2006;England et al 2006;Alken and Maus 2007;.…”

Section: Eejmentioning

confidence: 99%

Sq and EEJ—A Review on the Daily Variation of the Geomagnetic Field Caused by Ionospheric Dynamo Currents

2016

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A record of the geomagnetic field on the ground sometimes shows smooth daily variations on the order of a few tens of nano teslas. These daily variations, commonly known as Sq, are caused by electric currents of several μA/m 2 flowing on the sunlit side of the Eregion ionosphere at about 90-150 km heights. We review advances in our understanding of the geomagnetic daily variation and its source ionospheric currents during the past 75 years. Observations and existing theories are first outlined as background knowledge for the nonspecialist. Data analysis methods, such as spherical harmonic analysis, are then described in detail. Various aspects of the geomagnetic daily variation are discussed and interpreted using these results. Finally, remaining issues are highlighted to provide possible directions for future work.

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“…It is therefore, not only desirable but necessary that similar works should be done for different seasons using the same model and procedure, in order to confirm or derogate the various interesting findings reported in ONWUMECHILI and AGU (1981), This is our objective in the present paper. We have consequently employed the same POGO data, but for two different seasons of December (winter solstice) 1968 and June (summer solstice) 1969, within a broader time interval of 09-15 hr LT, that includes morning data.…”

Section: Introductionmentioning

confidence: 92%

“…The analysis was based on the method of ONWUMECHILI and AGU (1981). The data for the two soistitial seasons were analysed according to local times 09, 13 and 14 hr for December 1968 and10, 11, 12, 13, 14, 15 hr for June 1969.…”

Section: Analysis Of Datamentioning

confidence: 99%

See 1 more Smart Citation

Global Variations of the POGO electrojet parameters during the solstices.

Ozoemena

Onwumechili

1987

J. geomagn. geoelec

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Longitudinal variation of equatorial electrojet parameters derived from POGO satellite observations

Cited by 56 publications

References 12 publications

Equatorial electrojet at African longitudes: first results from magnetic measurements

Equatorial electrojet at African longitudes: first results from magnetic measurements

Sq and EEJ—A Review on the Daily Variation of the Geomagnetic Field Caused by Ionospheric Dynamo Currents

Global Variations of the POGO electrojet parameters during the solstices.

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