foF2 frequency bands in el cerrillo, Mexico during magnetically quiet conditions

Araujo-Pradere, E. A.

doi:10.1590/s0102-261x1997000200006

Cited by 3 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…foF2 semiannual anomaly in Ouagadougou area is a characteristic of foF2 (see Yonezawa, 1959;Rishbeth and Garriott, 1969;Yonezawa 1972;Huang and Cheng, 1996;Araujo-Pradere, 1997;Zou et al, 2000;Rishbeth et al, 2000;Zhang et al, 2005). This anomaly can be explained by transequatorial summer-winter neutral wind (Huang and Cheng, 1996) which increases the O/O 2 ratio in the winter hemisphere (Rees et al, 1987) and would lead to a greater local production rate of ionization in the winter hemisphere (Huang and Cheng, 1996).…”

Section: Synthesis and Discussionmentioning

confidence: 99%

West African equatorial ionospheric parameters climatology based on Ouagadougou ionosonde station data from June 1966 to February 1998

et al. 2009

View full text Add to dashboard Cite

Abstract. This study is the first which gives the climatology of West African equatorial ionosphere by using Ouagadougou station through three solar cycles. It has permitted to show the complete morphology of ionosphere parameters by analyzing yearly variation, solar cycle and geomagnetic activity, seasonal evolution and diurnal development. This work shows that almost all ionospheric parameters have 11-year solar cycle evolution. Seasonal variation shows that only foF2 exhibits annual, winter and semiannual anomaly. foF2 seasonal variation has permitted us to identify and characterize solar events effects on F2 layer in this area. In fact (1) during quiet geomagnetic condition foF2 presents winter and semiannual anomalies asymmetric peaks in March/April and October. (2) The absence of winter anomaly and the presence of equinoctial peaks are the most visible effects of fluctuating activity in foF2 seasonal time profiles. (3) Solar wind shock activity does not modify the profile of foF2 but increases ionization. (4) The absence of asymmetry peaks, the location of the peaks in March and October and the increase of ionization characterize recurrent storm activity. F1 layers shows increasing trend from cycle 20 to cycle 21. Moreover, E layer parameters seasonal variations exhibit complex structure. It seems impossible to detect fluctuating activity effect in E layer parameters seasonal variations but shock activity and wind stream activity act to decrease E layer ionization. It can be seen from Es layer parameters seasonal variations that wind stream activity effect is fairly inCorrespondence to: F. Ouattara (fojals@yahoo.fr) dependent of solar cycle. E and Es layers critical frequencies and virtual heights diurnal variations let us see the effects of the greenhouse gases in these layers.

show abstract

Section: Synthesis and Discussionmentioning

confidence: 99%

West African equatorial ionospheric parameters climatology based on Ouagadougou ionosonde station data from June 1966 to February 1998

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The investigation goals are: 1) to see the effect of geomagnetic storm (e.g. [13] Jones; [14] Jones and Risbeth; [15] Lal; [16] Araujo-Pradere; [17] Lal; [18] Obrou et al; [19] Le Huy et al; [20] Zhang et al; [21] Ouattara and Fleury); 2) to analyze ionosphere variability ( [22] Huang and Cheng; [23] Bilitza; [24] Özgüç et al; [25] Ouattara et al; [26] Thiam et al); [27] Gnabahou and Ouattara; [28] Ksouri et al; [29] Sambou et al ); 3) to model ionosphere parameters (e.g. [30] Adeniyi and Adimula, [ Gnabahou and Ouattara) and that at Ouagadougou station ([10] Ouattara and Amory Mazaudier) show some similitude, and this induces that the foF2 variations at this African sector are not only due to longitude effect.…”

Section: Introductionmentioning

confidence: 99%

foF2 Diurnal Variability at African Equatorial Stations: Dip Equator Secular Displacement Effect

Gnabahou¹,

Ouattara²,

Nanéma³

et al. 2013

IJG

View full text Add to dashboard Cite

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.

show abstract

“…It is well known that the F layer depends on: (1) the sunspot solar cycle (Phillips 1947;Forbes et al 2000;Forbes et al 2000;Rishbeth & Mendillo 2001;Pancheva et al 2002), (2) the Sun-Earth relative position at the origin of the seasonal variation, and equinoctial maxima (Lal 1992(Lal , 1997(Lal , 1998Arauje-Pradere 1997;Rishbeth et al 2000;Zou et al 2000) and (3) the solar wind speed Lotko 1989;Lal 1997Lal , 1998Ouattara 2009a;) and shock activity (Ouattara 2009b;). Solar wind speed and shock activity are the main sources of geomagnetic activity.…”

Section: Introductionmentioning

confidence: 99%

Statistical study of the equatorial F₂layer critical frequency at Ouagadougou during solar cycles 20, 21 and 22, using Legrand and Simon’s classification of geomagnetic activity

Ouattara

Amory‐Mazaudier

2012

J. Space Weather Space Clim.

View full text Add to dashboard Cite

This paper presents the statistical analysis of the diurnal variations of the F layer at the equatorial station of Ouagadougou (Lat: 12.4°N; Long: 358.5°E; dip: 5.9°) from 1966 to 1998 (=>~11 680 days). We consider three main factors of variability: (1) the season (spring, summer, autumn and winter), (2) the phase of the sunspot cycle (ascending, maximum, descending and minimum) and (3) the geomagnetic activity classified by Legrand and Simon in four groups: slow solar wind, high solar wind streams, fluctuating solar wind and shock activity. We easily identify the influence of the solar wind speed and shock activity on the diurnal pattern of the F layer. Shock and recurrent activities tend to enhance or diminish the morning or afternoon maximum of the F2 layer critical frequency. The difference of the diurnal foF2 variation during the increasing and decreasing phases of the sunspot solar cycle is explained by different solar wind regimes. The slow solar wind dominates during the increasing phase of the sunspot cycle and the fluctuating solar wind dominates during the decreasing phase of the sunspot cycle. This paper demonstrates that it is possible using a large database, to bring up significant morphologies of the diurnal variation of the foF2 critical frequency as a function of (1) different solar events such as quiet solar wind, fluctuating wind, recurrent high stream wind and Coronal Mass Ejections (CMEs); (2) solar cycle phases and (3) seasons. It is an approach directly connecting the critical frequency of the F2 layer to the solar parameters.

show abstract

foF2 frequency bands in el cerrillo, Mexico during magnetically quiet conditions

Cited by 3 publications

References 0 publications

West African equatorial ionospheric parameters climatology based on Ouagadougou ionosonde station data from June 1966 to February 1998

West African equatorial ionospheric parameters climatology based on Ouagadougou ionosonde station data from June 1966 to February 1998

foF2 Diurnal Variability at African Equatorial Stations: Dip Equator Secular Displacement Effect

Statistical study of the equatorial F₂layer critical frequency at Ouagadougou during solar cycles 20, 21 and 22, using Legrand and Simon’s classification of geomagnetic activity

Contact Info

Product

Resources

About

foF2 frequency bands in el cerrillo, Mexico during magnetically quiet conditions

Cited by 3 publications

References 0 publications

West African equatorial ionospheric parameters climatology based on Ouagadougou ionosonde station data from June 1966 to February 1998

West African equatorial ionospheric parameters climatology based on Ouagadougou ionosonde station data from June 1966 to February 1998

foF2 Diurnal Variability at African Equatorial Stations: Dip Equator Secular Displacement Effect

Statistical study of the equatorial F2layer critical frequency at Ouagadougou during solar cycles 20, 21 and 22, using Legrand and Simon’s classification of geomagnetic activity

Contact Info

Product

Resources

About

Statistical study of the equatorial F₂layer critical frequency at Ouagadougou during solar cycles 20, 21 and 22, using Legrand and Simon’s classification of geomagnetic activity