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Found 8 entries in the Bibliography.
Showing entries from 1 through 8
Solar and interplanetary events that drove two CIR-related geomagnetic storms of 1 June 2013 and 7 October 2015, and their ionospheric responses at the American and African equatorial ionization Anomaly regions
This study investigates the sequence of solar and interplanetary events that drove the 1 June 2013 and October 2015 geomagnetic storms and how the American (68°–78oE) and African (32°–42oE) Equatorial Ionization Anomaly (EIA) regions responded to them. We constructed the EIA structures by using Total Electron Content (TEC) and ionospheric irregularities derived from Global Navigation Satellite System (GNSS) receivers along with the study locations. We also analyzed disturbed time ionospheric electric field and model da ...
Oyedokun, Oluwole; Amaechi, P.; Akala, A.; Simi, K.; Ogwala, Aghogho; Oyeyemi, E.;
Published by: Advances in Space Research Published on: mar
YEAR: 2022   DOI: 10.1016/j.asr.2021.12.027
geomagnetic storm; total electron content; Corotating Interacting Region; ionospheric irregularities
Climatology of global, hemispheric and regional electron content variations during the solar cycles 23 and 24
We present the results of study on the variations of ionospheric total electron content (TEC) by using global, hemispheric, and regional electron contents computed from the global ionospheric maps (GIMs) for the period from 1999 to 2020. For a low and moderate solar activity, the global and regional electron contents vary linearly with solar 10.7 cm radio flux and EUV flux. While a saturation effect in the electron content verses EUV and F10.7 is found during the high solar activity periods at all regions, the maximum effec ...
Younas, Waqar; Amory-Mazaudier, C.; Khan, Majid; Amaechi, Paul;
Published by: Advances in Space Research Published on: jul
YEAR: 2022   DOI: 10.1016/j.asr.2022.07.029
annual variation; global electron content; Ionosphere; semi-annual variation; total electron content
Middle and low latitudes hemispheric asymmetries in ∑O/N2 and TEC during intense magnetic storms of solar cycle 24
We have investigated the global hemispheric differences in thermospheric ∑O/N2 and its impact on the ionospheric total electron content (TEC) at mid- and low-latitudes. Four intense storms of solar cycle 24 (SC-24) have been considered, three of them occurred in Spring equinox and one in Summer solstice season. It is found that the mid-latitudes region has exhibited a large decrease in ∑O/N2 during all the phases of the storms under consideration, which corresponds well to the observed negative storm effects. This decrea ...
Younas, Waqar; Khan, Majid; Amory-Mazaudier, C.; Amaechi, Paul; Fleury, R.;
Published by: Advances in Space Research Published on: jan
YEAR: 2022   DOI: 10.1016/j.asr.2021.10.027
CTIPe model; Disturbed ∑O/N; GUVI/TIMED data; Hemispheric asymmetries; REC
Middle and low latitudes hemispheric asymmetries in∑ O/N2 and TEC during intense magnetic storms of Solar Cycle 24
We have investigated the global hemispheric differences in thermospheric ∑O/N2 and its impact on the ionospheric total electron content (TEC) at mid- and low-latitudes. Four intense storms of solar cycle 24 (SC-24) have been considered, three of them occurred in Spring equinox and one in Summer solstice season.
Younas, Waqar; Khan, Majid; Amory-Mazaudier, C; Amaechi, Paul; Fleury, R;
Published by: Advances in Space Research Published on:
YEAR: 2022   DOI: 10.1016/j.asr.2021.10.027
Responses of the Indian Equatorial Ionization Anomaly to two CME-induced geomagnetic storms during the peak phase of solar cycle 24
This work analyzes the geo-effectiveness of Coronal Mass Ejection- (CME-) induced storms by investigating the responses of ionospheric Vertical Total Electron Content (VTEC) and the Equatorial Ionization Anomaly (EIA) over the Indian sector to two storms. One of the storms occurred on February 19, 2014 (SYM-H: −120 nT), while the other occurred on June 23, 2015 (SYM-H: −204 nT). Both storms were driven by full halo CMEs. Global TEC maps were used to characterize VTEC variations during the storms. June 23, 2015 storm was ...
Simi, K.; Akala, A.; Krishna, Siva; Amaechi, Paul; Ogwala, Aghogho; Ratnam, Venkata; Oyedokun, O.;
Published by: Advances in Space Research Published on: oct
YEAR: 2021   DOI: 10.1016/j.asr.2021.06.013
Coronal mass ejection; Disturbance dynamo electric field; geomagnetic storm; prompt penetration electric field; total electron content
Assessment of the predictive capabilities of NIGTEC model over Nigeria during geomagnetic storms
The Nigerian Total Electron Content (NIGTEC) is a regional neural network-based model developed by the Nigerian Centre for Atmospheric Research to predict the Total Electron Content (TEC) at any location over Nigeria. The addition of the disturbance storm time (Dst) index as one of NIGTEC s input layer neurons raises a question of its accuracy during geomagnetic storms. In this paper, the capability of NIGTEC in predicting the variability of TEC during geomagnetic storms has been assessed. TEC data predicted by NIGTEC is com ...
Amaechi, Paul; Humphrey, Ibifubara; Adewoyin, David;
Published by: Geodesy and Geodynamics Published on: nov
YEAR: 2021   DOI: 10.1016/j.geog.2021.09.003
geomagnetic storm; global navigation satellite system; Nigerian Total Electron Content (NIGTEC); total electron content
Comparison of ionospheric anomalies over African equatorial/low-latitude region with IRI-2016 model predictions during the maximum phase of solar cycle 24
The capability of IRI-2016 in reproducing the hemispheric asymmetry, the winter and semiannual anomalies has been assessed over the equatorial ionization anomaly (EIA) during quiet periods of years 2013–2014. The EIA reconstructed using Total Electron Content (TEC) derived from Global Navigation Satellite System was compared with that computed using IRI-2016 along longitude 25° − 40oE. These were analyzed along with hemispheric changes in the neutral wind derived from the horizontal wind model and the TIMED GUVI columna ...
Amaechi, Paul; Oyeyemi, Elijah; Akala, Andrew; Kaab, Mohamed; Younas, Waqar; Benkhaldoun, Zouhair; Khan, Majid; Mazaudier, Christine-Amory;
Published by: Advances in Space Research Published on: aug
YEAR: 2021   DOI: 10.1016/j.asr.2021.03.040
Equatorial ionization anomaly; hemispheric asymmetry; IRI-2016; Semiannual anomaly; Winter anomaly
Solar Origins of August 26, 2018 Geomagnetic Storm: Responses of the Interplanetary Medium and Equatorial/Low-Latitude Ionosphere to the Storm
This study investigates the solar origins of August 26, 2018 geomagnetic storm and the responses of the interplanetary medium and equatorial/low-latitude ionosphere to it. We used a multiinstrument approach, with observations right from the solar surface to the Earth. Our results showed that the G3 geomagnetic storm of August 26, 2018 was initiated by a solar filament eruption of August 20, 2018. The storm was driven by an aggregation of weak Coronal Mass Ejection (CME) transients and Corotating Interaction Regions/High Spee ...
Akala, A.; Oyedokun, O.; Amaechi, P.; Simi, K.; Ogwala, A.; Arowolo, O.;
Published by: Space Weather Published on:
YEAR: 2021   DOI: 10.1029/2021SW002734