Relationship between the equatorial electrojet and global sq currents at the dip equator region

Nurul Shazana Abdul Hamid, Huixin Liu, Teiji Uozumi, Kiyohumi Yumoto, Bhaskara Veenadhari, Akimasa Yoshikawa, Jairo Avendaño Sanchez

Research output: Contribution to journalLetter

19 Citations (Scopus)

Abstract

The equatorial electrojet (EEJ) is a strong eastward ionospheric current flowing in a narrow band along the dip equator. In this study, we examined the EEJ-Sq relationship by using observations at six stations in the South American, Indian, and Southeast Asian sectors. The analysis was carried out with data on geomagnetically quiet days with Kp ≤3 from 2005 to 2011. A normalization approach was used because it yields more accurate results by overcoming the uncertainties due to latitudinal variation of the EEJ and Sq. A weak positive correlation between the EEJ and Sq was obtained in the Southeast Asian sector, while weak negative correlations were obtained in the South American and Indian sectors. EEJ-Sq relationship is found to be independent of the hemispheric configuration of stations used to calculate their magnetic perturbations, and it also only changed slightly during low and moderate solar activity levels. These results demonstrate that the Southeast Asian sector is indeed different from the Indian and South American sectors, which is indicative of unique physical processes particularly related to the electro-dynamo. Furthermore, we also demonstrate that the definition of the EEJ, that is, the total current or enhanced current, can significantly affect the conclusions drawn from EEJ-Sq correlations.

Original languageEnglish
Article number146
JournalEarth, Planets and Space
Volume66
Issue number1
DOIs
Publication statusPublished - 1 Jan 2014

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equatorial electrojet
electrojet
equators
dip
sectors
American Indians
stations
ionospheric currents
solar activity
narrowband
perturbation
configurations

Keywords

  • Equatorial electrojet
  • H component
  • Longitudinal dependence
  • Sq current

ASJC Scopus subject areas

  • Geology
  • Space and Planetary Science

Cite this

Relationship between the equatorial electrojet and global sq currents at the dip equator region. / Abdul Hamid, Nurul Shazana; Liu, Huixin; Uozumi, Teiji; Yumoto, Kiyohumi; Veenadhari, Bhaskara; Yoshikawa, Akimasa; Sanchez, Jairo Avendaño.

In: Earth, Planets and Space, Vol. 66, No. 1, 146, 01.01.2014.

Research output: Contribution to journalLetter

Abdul Hamid, Nurul Shazana ; Liu, Huixin ; Uozumi, Teiji ; Yumoto, Kiyohumi ; Veenadhari, Bhaskara ; Yoshikawa, Akimasa ; Sanchez, Jairo Avendaño. / Relationship between the equatorial electrojet and global sq currents at the dip equator region. In: Earth, Planets and Space. 2014 ; Vol. 66, No. 1.
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AB - The equatorial electrojet (EEJ) is a strong eastward ionospheric current flowing in a narrow band along the dip equator. In this study, we examined the EEJ-Sq relationship by using observations at six stations in the South American, Indian, and Southeast Asian sectors. The analysis was carried out with data on geomagnetically quiet days with Kp ≤3 from 2005 to 2011. A normalization approach was used because it yields more accurate results by overcoming the uncertainties due to latitudinal variation of the EEJ and Sq. A weak positive correlation between the EEJ and Sq was obtained in the Southeast Asian sector, while weak negative correlations were obtained in the South American and Indian sectors. EEJ-Sq relationship is found to be independent of the hemispheric configuration of stations used to calculate their magnetic perturbations, and it also only changed slightly during low and moderate solar activity levels. These results demonstrate that the Southeast Asian sector is indeed different from the Indian and South American sectors, which is indicative of unique physical processes particularly related to the electro-dynamo. Furthermore, we also demonstrate that the definition of the EEJ, that is, the total current or enhanced current, can significantly affect the conclusions drawn from EEJ-Sq correlations.

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