Interplanetary Origins of Intense Geomagnetic Storms during Solar Cycle 24: Their Implications on GNSS-Aviation Systems at the African Equatorial/Low Latitude Region
Abstract
We studied the interplanetary (IP) origins of the intense geomagnetic storms (GSs) (Dst≤ -100nT) that occurred during solar cycle (SC) 24 and their overall implications on GNSS-aviation at the African equatorial/low-latitude region. The roles of the IP Magnetic Field (IMF) and Solar Wind Plasma (SWP) parameters in the formation of these intense storms, 5 days prior to their main phases, and 5 days after, were critically investigated. The responses of GPS Total Electron Content (TEC), Rate of change of TEC (ROTI), GPS- and European Geostationary Navigation Overlay Service- (EGNOS-) scintillations (based on available data) at Cape Verde (16.00oN, 24.01oW geo. coordinates, 6.62oN mag. lat); Dakar (14.72oN, 17.43oW, 2.34oN) [Senegal] and Addis Ababa (9.04oN, 38.77oE, 0.18oN) [Ethiopia] to the GSs were analyzed. Generally, we studied 20 intense GSs. All, except 2 were driven by Interplanetary Coronal Mass Ejection (ICME) related transients (Magnetic Clouds (MCs): 22.2%, sheath fields: 38.9% and combinations of MCs and sheath fields: 27.8%). Two (1/06/2013 and 7/10/2015) of the GSs (11.1%) were driven by Co-rotating Interaction Regions (CIRs). TEC showed reductions for GSs that occurred during the night-time hours and enhancements for those that occurred during the day-time hours. ROTI values (irregularities occurrences) were generally inhibited by the GSs occurrences over the study locations, except for few cases where the GSs caused enhancements in irregularities. GPS- and EGNOS-scintillations showed the same trend as the ionospheric irregularities. Overall, the responses of the African equatorial/low-latitude ionosphere to GSs are dependent on factors such as the location's local time when the GS starts unfolding, GS's intensity, season and solar activity.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSA31B..05A
- Keywords:
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- 7924 Forecasting;
- SPACE WEATHER;
- 7934 Impacts on technological systems;
- SPACE WEATHER;
- 7944 Ionospheric effects on radio waves;
- SPACE WEATHER