Investigation of ionospheric minimum frequency near dip equator

Research output: Contribution to journalArticle

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Abstract

The ionospheric minimum frequency (fmin) is the lowest possible frequency below which high-frequency radio signal can not be propagated through the ionosphere. In this study, we use digisonde measurements obtained from Ilorin (8.5 ºN, 4.5 ºE) and Jicamarca (12 ºS, 76.87 ºW) station respectively to examine the variations in the fmin near the dip equator. This work covers the year of 2010 which has a 27-day averaged F10.7 to be 80 sfu, indicating a year of low solar activity. This result shows that fmin is higher during the daytime and lower during night time for both stations. Generally, for all season, the midday maximum value for Ilorin station was observed between the frequency ranges of 2.3–2.7 MHz while that of Jicamarca station is between 2.3 to 2.9 MHz. The night time threshold frequency for both stations was observed to be between the frequency range of 1.90 to 2.20 MHz. Consequentially, propagating radio frequency less than the obtained threshold frequency within this region are likely to be attenuated or possibly absorbed. The relative variability (VR) index for both stations was studied. We found that the VR index for Ilorin station is consistent, having a higher value during the night time and lower during the daytime. However, the VR index for Jicamarca station was observed to be relatively unstable throughout the day. The disparity observed in the VR index for both stations suggested that fmin varies with longitude.

Original languageEnglish
Pages (from-to)1329-1332
Number of pages4
JournalAdvanced Science Letters
Volume23
Issue number2
DOIs
Publication statusPublished - 1 Feb 2017

Fingerprint

Equator
dip
Radio
Ionosphere
Solar Activity
radio
Longitude
Range of data
Low Frequency
station
Unstable
Likely
Vary
Cover
time
solar activity
ionosphere

Keywords

  • Fmin
  • Ionospheric ceiling
  • Ionospheric minimum frequency
  • Variability

ASJC Scopus subject areas

  • Health(social science)
  • Computer Science(all)
  • Education
  • Mathematics(all)
  • Environmental Science(all)
  • Engineering(all)
  • Energy(all)

Cite this

Investigation of ionospheric minimum frequency near dip equator. / Bello, Saeed Abioye; Abdullah, Mardina; Abdul Hamid, Nurul Shazana.

In: Advanced Science Letters, Vol. 23, No. 2, 01.02.2017, p. 1329-1332.

Research output: Contribution to journalArticle

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