The response of the ionosphere over Ilorin to some geomagnetic storms

Joshua, B.W.; Adeniyi, J.O.; Reinisch, B. W.; Adimula, I. A.; Olawepo, A.O.; Oladipo, O.A.; Adebiyi, S.J.

doi:10.1016/j.asr.2014.08.027

Cited by 8 publications

(8 citation statements)

References 57 publications

(82 reference statements)

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“…Many recent and past studies (e.g., Adebiyi et al, 2014;Bagiya et al, 2009;Buresova & Lastovicka, 2007;Chukwuma, 2011;David, 2013;Danilov, 2013Danilov, , 2001Danilov & Konstantinova, 2019Danilov et al, 1985;Liu et al, 2008;Joshua et al, 2014b;Kane, 1973;Mikhailov & Perrone, 2009Saranya et al, 2011;Zhang et al, 2021) have reported/studied enhancement in foF2/ NmF2 during quiet days that precede geomagnetic storm commencement. These increases or decreases in NmF2 are normally not expected under geomagnetically quiet conditions, considering the Dst value.…”

Section: Discussionmentioning

confidence: 99%

“…This suggests a possibility of penetration of the auroral electric field to the equatorial and low latitudes during such periods leading to the modification of the equatorial electric field pattern and consequently the ExB drift (Joshua et al., 2014a; Liu et al., 2008). Many studies (Adebiyi et al., 2014; Danilov & Belik, 1992; Danilov et al., 1985; Joshua et al., 2014b) have also attributed PMSs to neutral composition due to the modification of the dayside cusp as a result of particle precipitation.…”

Section: Discussionmentioning

confidence: 99%

“…(1998) has shown that one of the main signatures of any geomagnetic storm is the development of a ring current and its consequent recovery. The response of the Ionosphere to geomagnetic storms has been studied extensively by previous and recent authors like: (Adeniyi, 1986; Akala et al., 2013; Blagoveshchensky & Sergeeva, 2017; Buonsanto, 1999; Chigomezyo et al., 2012; De Abreu et al., 2014; Fejer, 2002; John et al., 2013; Joshi et al., 2016; Joshua, et al., 2014a, 2014b, 2018, 2021; Kane, 1973; Lin et al., 2005; Liu et al., 2008; Mikhailov et al., 1994; Olawepo & Adeniyi, 2012; Onwumechili et al., 1973, Rishbeth, 1977; Sastri et al., 2002; Sharma et al., 2012; Shimeis et al., 2012, 2015; Sobral et al.,2001; Tsurutani et al., 2004, and much more). In spite of the increasing number of studies in this area, there are still features and mechanisms of some ionospheric disturbances that have not been fully understood.…”

Section: Introductionmentioning

confidence: 99%

“…The subject of (or the debate on) PMS has existed for decades and were said to have been formulated for the first time by Danilov (Mikhailov and Perron, 2009) and has appeared in so many literatures since then (Adebesin & Adekoya, 2013; Adebiyi et al., 2014, 2015; Adekoya, et al., 2012; Bagiya et al., 2009; Blagoveshchensky et al., 2006; Buresova & Lastovicka, 2007, 2008; Chukwuma, 2007, 2011; Danilov, 2013; Danilov, 2001; Danilov & Konstantinova, 2019; David, 2013; Joshua et al., 2014a, 2014b, 2018; Kane, 2005; Lin et al., 2012; Liu et al., 2008; Mikhailov & Perrone, 2009; Saranya et al., 2011, and many more). Negative phases or decreases of critical frequency (foF2), NmF2, and TEC were also reported for low and mid latitude stations during the PMS (Adebesin & Adekoya, 2013; Adebiyi, et al., 2015; Adekoya, et al., 2012; Lin et al., 2012).…”

Section: Introductionmentioning

confidence: 99%

“…The possible cause of PMS and its relationship to the geomagnetic storm has been a great challenge in the study of ionospheric responses to geomagnetic storms (Chukwuma, 2011; Liu et al., 2008) and was earlier considered by Danilov (2001) as one of the open or unsolved problems of the physics of the F2 region. The complex nature of PMS has forced some researchers to avoid the use of few days before the commencement of geomagnetic storm events, focusing mostly on the geomagnetic storm days only (Joshua et al., 2014b). Buresova and Lastovicka (2007) have also shown that the phenomenon of PMS is given less attention than the geomagnetic storm‐time behavior.…”

Section: Introductionmentioning

confidence: 99%

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On the Pre‐Magnetic Storm Signatures in NmF2 in Some Equatorial, Low‐ and Mid‐Latitude Stations

et al. 2021

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In this paper, the ionospheric quiet‐time disturbances otherwise known as Pre‐Magnetic Storm Signatures (PMS) have been studied using the F2‐layer peak electron density (NmF2) data obtained from 12 Digisonde/ionosonde stations distributed across equatorial, low and mid‐latitudes. The datasets used spans the years 2010–2012. Results from this study reveals strong PMS in NmF2 with percentage deviations (ΔNmF2) ranging from −91% to 500% at the equatorial, low and mid‐latitudes, with maxima occurring at the equatorial region. Significant effects on the peak height of the F2‐layer (hmF2) were also observed, and they are correlated with the variations in NmF2 particularly at the equatorial station during the PMS. The duration of a PMS is found to be 12–48 h. Although, it was difficult to state clearly the connection between the PMS and the geomagnetic storm that usually follows within 24–48 h; but the NmF2 and hmF2 responses during the PMS were quite similar to those observed during geomagnetic storms. A slight increase in the Solar‐wind‐plasma speed (>20 km/s) was also observed during PMS. The PMS occur under a southward IMF‐Bz, moderate aurora activity (AE ranging from 114 to 560 nT) and quiet ring current (Dst >−10 nT). Therefore, it is pertinent to consider a certain threshold of the aurora indices (AE, AL, and AU) in addition to the Dst, ap, and Kp in the definition of a geomagnetically quiet day. This may eliminate the ambiguity in explaining the ionospheric variability that occurs few days before Sudden Storm Commencement (SSC).

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Pre‐Magnetic Storm Signatures in NmF2 in Some Equatorial, Low‐ and Mid‐Latitude Stations

et al. 2021

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Latitudinal and Seasonal Investigations of Storm-Time TEC Variation

Adimula

Oladipo

Adebiyi

2016

Pure Appl. Geophys.

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The ionosphere responds markedly and unpredictably to varying magnetospheric energy inputs caused by solar disturbances on the geospace. Knowledge of the impact of the space weather events on the ionosphere is important to assess the environmental effect on the operations of ground-and space-based technologies. Thus, global positioning system (GPS) measurements from the international GNSS service (IGS) database were used to investigate the ionospheric response to 56 geomagnetic storm events at six different latitudes comprising the northern and southern hemispheres in the Afro-European sector. Statistical distributions of total electron content (TEC) response show that during the main phase of the storms, enhancement of TEC is more pronounced in most of the seasons, regardless of the latitude and hemisphere. However, a strong seasonal dependence appears in the TEC response during the recovery phase. Depletion of TEC is majorly observed at the high latitude stations, and its appearance at lower latitudes is seasonally dependent. In summer hemisphere, the depletion of TEC is more pronounced in nearly all the latitudinal bands. In winter hemisphere, enhancement as well as depletion of TEC is observed over the high latitude, while enhancement is majorly observed over the mid and low latitudes. In equinoxes, the storm-time TEC distribution shows a fairly consistent characteristic with the summer distribution, particularly in the northern hemisphere.

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