|
Notice:
|
Found 8 entries in the Bibliography.
Showing entries from 1 through 8
| 2022 |
|
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 |
|
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 |
|
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 |
|
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 |
| 2021 |
|
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 |
|
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 |
|
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 |
1