TITLE:
Comparative Study of the Geomagnetic Activity Effect on foF2 Variation as Defined by the Two Classification Methods at Dakar Station over Solar Cycle Phases
AUTHORS:
Sibri Alphonse Sandwidi, Doua Allain Gnabahou, Frédéric Ouattara
KEYWORDS:
Geomagnetic Activity Classification Method, Solar Cycle Phases, foF2 Diurnal Profile
JOURNAL NAME:
International Journal of Geosciences,
Vol.11 No.8,
August
17,
2020
ABSTRACT: This paper aims to establish a comparison between
both geomagnetic activity classification methods on foF2 diurnal variation over
solar cycle phases. It concerns first a comparison of geomagnetic activity
occurrences according to both classification methods; and second the
geomagnetic effect on foF2 diurnal variation profiles as defined for the
equatorial latitudes. The occurrences of the different disturbed geomagnetic
activities (recurrent activity (RA), shock activity (SA) and fluctuant activity
(FA)) according to both classifications (ancient classification (AC) and new
classification (NC)) have been studied at Dakar ionosonde station (Lat: 14.8°N;
Long: 342.6°E). Regarding both classifications, the RA occurs more during the
decreasing phase. And it’s observed that the RA occurs the most during the
increasing phase for the AC and during the minimum phase for the NC. The
maximum gap of occurrence () between both classifications is ᆟ.1% (for the negative value which is observed
during the increasing phase) and +16.74% (for the positive one which is observed during the decreasing phase).
The occurrence of the SA in relation with both classifications is the lowest
during the minimum phase and the maximum occurrence is observed during the
maximum and decreasing phases, for the AC, with a value close to 37% and for the NC at the maximum phase with a
percentage of 54.47%. The
maximum gap of occurrence () between both classifications is ᆥ.85% (for the negative value which is observed at
maximum phase) and +13.53% (for
the positive one which is observed during the decreasing phase). For both
classifications, the FA occurs the least during the minimum phase and the most
during the maximum phase for the AC and at maximum and decreasing phases with
percentage values of occurrence of roughly 37% for the NC. The maximum gap of occurrence () between both classifications is ᆞ% (for the
negative value which is observed during the decreasing phase) and +20.11% (for the positive one which is observed
during the maximum phase). foF2 diurnal profiles throughout solar cycle phases
concerning the AC and the NC have been compared. The FA diurnal profiles don’t
present a difference. The RA and the SA present a difference during minimum and
increasing phases and the least at maximum and decreasing phases.