Longitudinal variation of equatorial electrojet and the occurrence of its counter electrojet

A. Babatunde Rabiu, Olanike Olufunmilayo Folarin, Teiji Uozumi, Nurul Shazana Abdul Hamid, Akimasa Yoshikawa

Research output: Contribution to journalArticle

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Abstract

We examined the longitudinal variability of the equatorial electrojet (EEJ) and the occurrence of its counter electrojet (CEJ) using the available records of the horizontal component H of the geomagnetic field simultaneously recorded in the year 2009 (mean annual sunspot number Rz Combining double low line 3.1) along the magnetic equator in the South American, African, and Philippine sectors. Our results indicate that the EEJ undergoes variability from one longitudinal representative station to another, with the strongest EEJ of about 192.5nT at the South American axis at Huancayo and a minimum peak of 40.7nT at Ilorin in western Africa. Obtained longitudinal inequality in the EEJ was explicable in terms of the effects of local winds, dynamics of migratory tides, propagating diurnal tide, and meridional winds. The African stations of Ilorin and Addis Ababa registered the greatest % of CEJ occurrence. Huancayo in South America, with the strongest electrojet strength, was found to have the least occurrence of the CEJ. It is suggested that activities that support strong EEJ inhibits the occurrence of the CEJ. Percentage of occurrence of the CEJ varied with seasons across the longitudes. The order of seasonal variation of morning occurrence does not tally with the evening occurrence order at any station. A semiannual equinoctial maximum in percentage of morning occurrence of the CEJ was obtained at Huancayo and Addis Ababa. Only Addis Ababa recorded equal equinoctial maxima in percentage of evening occurrence of the CEJ. The seasonal distribution of the occurrences of the CEJ at different time regimes implies a seasonal variability of causative mechanisms responsible for the occurrence of the CEJ.

Original languageEnglish
Pages (from-to)535-545
Number of pages11
JournalAnnales Geophysicae
Volume35
Issue number3
DOIs
Publication statusPublished - 7 Apr 2017

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equatorial electrojet
electrojets
electrojet
counters
occurrences
evening
morning
stations
tides
magnetic equator
Philippines
tide
annual variations
geomagnetism
sunspots
African American
sectors

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Geology
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Longitudinal variation of equatorial electrojet and the occurrence of its counter electrojet. / Babatunde Rabiu, A.; Folarin, Olanike Olufunmilayo; Uozumi, Teiji; Abdul Hamid, Nurul Shazana; Yoshikawa, Akimasa.

In: Annales Geophysicae, Vol. 35, No. 3, 07.04.2017, p. 535-545.

Research output: Contribution to journalArticle

Babatunde Rabiu, A. ; Folarin, Olanike Olufunmilayo ; Uozumi, Teiji ; Abdul Hamid, Nurul Shazana ; Yoshikawa, Akimasa. / Longitudinal variation of equatorial electrojet and the occurrence of its counter electrojet. In: Annales Geophysicae. 2017 ; Vol. 35, No. 3. pp. 535-545.
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