In this paper we investigate the fluctuations of solar activity and their links with climatic parameters in West Africa. We achieve our research by investigating several data plotted using averages. Mean to our results we can assume that active solar is associated with weak incident cosmic ray consequently with low cloudiness which brings warming. Likewise, quiet solar is associated with important cloud cover and consequently brings important precipitations and chills terrestrial atmosphere. This implies the necessity to deal with space phenomenon by considering the severe interconnection between solar activity indices for interplanetary and earth environment weather forecasting.
The paper goal is to analyze the variability of foF2 at African equatorial stations and the effect of dip angle on this variability. The gap between the dip angle of Dakar and Ouagadougou is superior to that between Djibouti and Ouagadougou. The trend of the dip angle at Ouagadougou and Dakar decreases while that of Djibouti increases. The relative position of the station with respect to the equator and the trend sign explains the difference observed in foF2 variability at Dakar station and at the two other stations. At Djibouti and Ouagadougou, foF2 exhibits noon bite out profile during all solar cycle phases while at Dakar observed profile is dome or plateau during the maximum and the predominance afternoon peak for the other solar cycle phases.
This study deals with Peak of electron density in F2-layer sensibility scale during quiet time on solar minimum. Peaks of electron density in F2-layer (NmF2) values at the quietest days are compared to those carried out from the two nearest days (previous and following of quietest day). The study uses International Reference Ionosphere (IRI) for ionosphere modeling. The located station is Ouagadougou, in West Africa. Solar minimum of phase 22 is considered in this study. Using three core principles of ionosphere modeling under IRI running conditions, the study enables to carry out Peak of electron density in F2-layer values during the quietest days of the characteristic months for the four different seasons. These parameters are compared to those of the previous and the following of the quietest days (the day before and following each quietest selected day) at the same hour. The knowledge of NmF2 values at the quietest days and at the two nearest days enables to calculate the relative error that can be made on this parameter. This calculation highlights insignificant relative errors. This means that NmF2 values at the two nearest days of each quietest day on solar minimum can be used for simulating the quietest days' behavior. NmF2 values obtained by running IRI model have good correlation with those carried out by Thermosphere-Ionosphere-Electrodynamics-General Circulation Model (TIEGCM).
The statistical study of F2 layer critical frequency at Dakar station from 1971 to 1996 is carried out. This paper shows foF2 statistical diurnal for all geomagnetic activities and all seasons and that during solar maximum and minimum phases. It emerges that foF2 diurnal variation graphs at Dakar station exhibits the different types of foF2 profiles in African EIA regions. The type of profile depends on solar activity, season and solar phase. During solar minimum and under quiet time condition, data show the signature of a strength electrojet that is coupled with intense counter electrojet in the afternoon. Under disturbed conditions, mean intense electrojet is observed in winter during fluctuating and recurrent activities. Intense counter electrojet is seen under fluctuating and shock activities in all seasons coupled with strength electrojet in autumn. In summer and spring under all geomagnetic activity condition, there is intense counter electrojet. During solar maximum, in summer and spring there is no electrojet under geomagnetic activity conditions. Winter shows a mean intense electrojet. Winter and autumn are marked by the signature of the reversal electric field.
Ionosphere investigation leads to the knowledge of its composition in particles. The particle density and composition determine the capacity of this region to reflect radio waves in the atmosphere at different heights. Some variables such as season, solar cycle phase also influence the ionosphere behavior. Radio waves frequencies pass through the ionosphere layer without reflection above a critical value determining the critical frequency. This study determines the critical frequency of radio waves in the F2 layer (foF2) of the ionosphere by use of data at Ouagadougou station during the minimum and the maximum of solar cycle 22, at different seasons with the height of F2-layer (hmF2). Daytime and nighttime also influence ionosphere parameters. The study presents the hourly behavior of foF2 according to hmF2 values.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.