Magnetic storm effects on the variation of TEC over Ilorin an equatorial station

Adeniyi, J.O.; Doherty, Patricia H.; Oladipo, O.A.; Bolaji, O. S.

doi:10.1002/2014rs005404

Cited by 11 publications

(8 citation statements)

References 27 publications

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“…It is understood that the F region in the equatorial latitude is highly influenced by electrodynamics even during quiet time disturbance periods (Buonsanto, , and references therein). The zonal electric fields on the equatorial ionosphere control vertical plasma transport in the low‐latitude ionosphere and drives the equatorial ionization anomalies and causes vertical drifts (Adeniyi et al, ; Shume et al, ). As reported extensively, dayside P ionospheric storm effects in equatorial regions are sometimes related to PPEF (Huang et al, ; Klimenko & Klimenko, ; Mannucci et al, ; Tsurutani et al, , ) and may depend on the strength of PPEF (Balan et al, ).…”

Section: Overall Statisticsmentioning

confidence: 99%

“…Adewale et al () showed that the positive ionospheric storm effects were more prevalent than negative ionospheric responses during the geomagnetic storm periods between April 2000 and November 2007 using TEC observed at Libreville, Gabon (0.35°N, 9.67°E; 8.05°S, geomagnetic). During the storm period of 2009–2012, Adeniyi et al () used TEC over Ilorin (8.47°N, 4.68°E; 1.84°S, geomagnetic) to study ionospheric dynamic and observed more positive ionospheric response in comparison with negative ionospheric storm effects.…”

Section: Introductionmentioning

confidence: 99%

“…Event(s) analyses of ionospheric storm effects over the African sector have been done during either CME-or CIR-driven storms (e.g., Habarulema et al, 2013Habarulema et al, , 2017Ngwira et al, 2012;Prölss et al, 1991;Yizengaw et al, 2011). Statistical analyses of ionospheric storm effects due to geomagnetic storms over middle and low latitude in the African sector have been done separately in different latitude regions (e.g., Adeniyi, 1986;Adeniyi et al, 2014;Adewale et al, 2011;Burešová et al, 2014;Matamba et al, 2015). This work presents statistical analyses of ionospheric storm effects due to CME-and CIR-driven storms simultaneously over middle, low, and equatorial latitudes in the African sector during the time interval 2001-2015 for the first time.…”

Section: Introductionmentioning

confidence: 99%

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Ionospheric Responses to CME‐ and CIR‐Driven Geomagnetic Storms Along 30°E–40°E Over the African Sector From 2001 to 2015

Matamba

Habarulema

2018

Space Weather

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In this paper, we present the responses of the ionospheric total electron content (TEC) to coronal mass ejection (CME)‐ and corotating interaction region (CIR)‐driven storms using stations that lie within 30°E–40°E geographic longitude in middle, low, and equatorial latitudes over the African sector. CIR‐driven storms are generally weak (−50 nT < Dst < −25 nT) to moderate (−100 nT < Dst < −50 nT) in intensity, while CME‐driven storms are often associated with the intense (Dst < −100 nT) geomagnetic storms. CIR‐driven storms have long recovery phase as compared to CME‐driven storms. CME‐ and CIR‐driven storms were classified based on the features of proton temperature, magnetic field, solar wind speed, and proton density. The storm periods analyzed occurred during the period 2001–2015, which covers part of solar cycles 23 and 24. Disturbance storm time (Dst) ≤ −30 nT and Kp ≥ 3 indices were used simultaneously to identify the storm periods considered. The total number of CME‐ and CIR‐driven storms identified was 148 and 167, respectively. However, due to lack of TEC data, the number of CME‐ and CIR‐driven storms considered for the middle‐latitude, low‐latitude, and equatorial latitude stations are different for different regions. TEC data used in this study was derived from the Global Navigation Satellite System observations. The statistical analysis of ionospheric storm effects were compared over middle, low, and equatorial latitudes in the African sector for the first time. Negative ionospheric storm effects occurred only during CME‐driven storms over midlatitude stations and were more prevalent in summer. For the low and equatorial latitudes, negative ionospheric storm effects were observed during both CME‐ and CIR‐driven storms. Our analysis has shown that positive ionospheric storm effects were more prevalent over middle, low, and equatorial latitudes during both CME‐ and CIR‐driven storms. A significant number of cases where the electron density changes remained within the background variability during storm conditions were observed over the low‐latitude stations compared to other latitude regions.

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Section: Overall Statisticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ionospheric Responses to CME‐ and CIR‐Driven Geomagnetic Storms Along 30°E–40°E Over the African Sector From 2001 to 2015

Matamba

Habarulema

2018

Space Weather

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“…Many studies were made using GPS derived ionospheric data (Obrou et al, 2009;Ouattara et al, 2012;Bolaji et al, 2012;Bolaji et al, 2013;Oladipo et al, 2014;Bolaji et al, 2015), on the solar cycle and the seasonal behavior of TEC (Moeketsi et al, 2007;Ackah et al, 2011;Zoundi et al, 2012;Shimeis et al, 2014), on magnetic storms Adeniyi et al, 2014;De Abreu et al, 2014;Shimeis et al, 2015;Azzouzi et al, 2015). This paper is the first paper in Africa devoted to the IHV of TEC.…”

mentioning

confidence: 99%

Inter-hourly variability of Total Electron Content during the quiet condition over Nigeria, within the Equatorial Ionization Anomaly region

Ayorinde

Rabiu

Amory‐Mazaudier

2016

Journal of Atmospheric and Solar-Terrestrial Physics

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To cite this version:T.T. Ayorinde, A. B Rabiu, Christine Amory-Mazaudier. Inter-hourly variability of total electron content during the quiet condition over Nigeria, within the equatorial ionization anomaly region. AbstractThe inter-hourly variability (IHV) of the Total Electron Content (TEC) over Nigeria during the quiet days (Ap<4) of the year 2013 was examined using ground-based GPS receivers installed at seven (7) different locations across Nigeria by the Nigerian Global Navigation Satellite Systems (GNSS) Reference Network (NIGNET) operated by the office of the surveyor general of Nigeria. Nigeria is a country that lies within equatorial ionospheric anomaly (EIA) region. The IHV was calculated by converting the observed hourly slant TEC (STEC) value into the hourly vertical TEC (VTEC) and the differencing (∆TEC) with its corresponding hourly value from the previous day. There is a clear variation which depicts the expected temporal variability. The IHV in TEC in all the stations ranges between 0-20 TECU (TEC Units). The seasonal variation of the IHV of TEC over Nigeria maximizes (5-20 TECU) during Equinoctial months and minimizes (1-10 TECU) during the Solstice months.The IHV of TEC in September equinox period is higher than that of March equinox. Minimum value of IHV (~7 TECU at equinoxes and ~5 TECU at Solstice) was recorded at the Office of Surveyor General of the Federation (OSGF) station and the maximum value (~12 TECU at equinoxes and ~16 TECU at Solstice) was recorded at the Birni Kebbi Federal Polytechnic (BKFP) station which may be due to the fact that BKFP at 0.72° dip latitude is closer to the dip equator.

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“…The seasonal trend observed could be pointing to the fact that the background ionosphere, in addition to the mechanism described above, is equally important in the generation and occurrence of ionospheric irregularities. Many studies including the ones done at Ilorin have shown that the level of ionization is higher during equinox months than during solstice months (e.g., Adeniyi et al, ; Oladipo et al, ). This could explain why the peak of scintillation occurs around March and September at Ilorin.…”

Section: Resultsmentioning

confidence: 99%

Ionospheric Scintillation Activity Over Ilorin, Nigeria

et al. 2018

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Scintillation of radio waves in the L‐band frequency is a regular occurrence at the equatorial and auroral regions at night most especially during high solar activity periods. Scintillation is caused by plasma density irregularities, and this could cause loss of lock of Global Navigation Satellite System (GNSS) signals leading to impairment of the applications that rely on this system. A study on the occurrence of scintillation activity over Ilorin (latitude = 8.48°N, longitude = 4.67°W, and geomagnetic latitude = 1.89°S), Nigeria was done using S4 index data from NovAtel GPStation‐2 receiver (2009–2012) and NovAtel GPStation‐6 receiver (August 2013 to December 2016) which are both located at this station. The solar maximum period of the solar cycle 24 is located well within the period of this investigation; hence, this study provides opportunity to see the occurrence pattern of scintillation during different seasons as well as the pattern from low solar activity to solar maximum. The results obtained showed that scintillation occurs between 21:00 LT and 04:00 LT at the peak of the occurrence in 2014. The time window of occurrence decreases with decrease in solar activity. Similarly, scintillation activity was observed to be more regular during high solar activity and it has two peaks of occurrence in March and October. A solar activity trend was observed in scintillation occurrence; scintillation activity increases with increase in the level of solar activity.

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Magnetic storm effects on the variation of TEC over Ilorin an equatorial station

Cited by 11 publications

References 27 publications

Ionospheric Responses to CME‐ and CIR‐Driven Geomagnetic Storms Along 30°E–40°E Over the African Sector From 2001 to 2015

Ionospheric Responses to CME‐ and CIR‐Driven Geomagnetic Storms Along 30°E–40°E Over the African Sector From 2001 to 2015

Inter-hourly variability of Total Electron Content during the quiet condition over Nigeria, within the Equatorial Ionization Anomaly region

Ionospheric Scintillation Activity Over Ilorin, Nigeria

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