Abstract
In this paper we report on the foF2 variabilities for two equatorial regions (Ouagadougou: Lat. 12.4°N; Long. 358.5°E, Dip. 1.43°S; and Manila: Lat. 14°36'15.12''N; Long. 120°58'55.92''E; Dip. 0.6°S) during solar cycles 20 and 21 minima and maxima phases. Many previous works have argued on the diurnal and seasonal variation of foF2 for different solar events conditions for latitudinal position. But there are few investigations for Africa equatorial region longitudinal variation. The present paper’s goal is to outline possible similarity in foF2 behavior between variations for better understanding of physical process lead to some observed phenomenon in Asia-Africa equatorial sector. The F-layer critical frequency (foF2) data observed from the two equatorial ionosonde stations have been used for the present comparative study. The results show significant similarity between the critical frequency (foF2) seasonal variations over the time intervals 1976-1996. During day-time measured data from Manila station are higher than those from Ouagadougou station. That may lie in that Manila is closer to equatorial ionization crest region. During solar minimum phase, the longitudinal variation of foF2 shows two crossing points (11:00 UT and 22:00 UT) between the foF2 profiles form the two stations for all seasons regardless of the solar cycle. However during intense solar activity condition, the number of crossing-point between measured data from Manila and Ouagadougou stations varies by seasons and solar cycle. This phenomenon may be due to the compilations of severe activities (storms, coronal mass ejection, heliosheet fluctuations) during the solar maximum phases.
Highlights
The ionosphere is one of the most important layers of the Earth atmosphere
In this paper we report on the foF2 variabilities for two equatorial regions (Ouagadougou: Lat. 12.4 ̊N; Long. 358.5 ̊E, Dip. 1.43 ̊S; and Manila: Lat. 14 ̊36'15.12''N; Long. 120 ̊58'55.92''E; Dip. 0.6 ̊S) during solar cycles 20 and 21 minima and maxima phases
The results show significant similarity between the critical frequency seasonal variations over the time intervals 1976-1996
Summary
The ionosphere is one of the most important layers of the Earth atmosphere. This layer ionized by solar and cosmic radiation is very important for waves and their propagations. [12] had reported on the variation of this ionospheric parameter through its in situ measurements in Africa equatorial region and classified foF2 diurnal profiles as follow: 1) morning peak profile characterized by a predominance morning peak; 2) plateau profile; 3) dome profile; 4) reverse profile characterized by predominant afternoon peak; and 5) noon bite out profile due to the presence of double peaks (morning and afternoon peaks) with trough around midday All these previous studies had provided suggestions and help on the improvement of the prediction of the equatorial ionosphere behavior for human well-being. The Final Section presents our findings and summarizes the paper
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
