Characteristics of nighttime E-region over Arecibo: Dependence on solar flux and geomagnetic variations
| Autor: | Efmi Franco, Christiano Garnett Marques Brum, Cristina Gonzalez, Shikha Raizada, John D. Mathews |
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| Rok vydání: | 2018 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences Total electron content Incoherent scatter Aerospace Engineering Astronomy and Astrophysics Equinox Atmospheric sciences 01 natural sciences Geophysics Altitude Earth's magnetic field Space and Planetary Science Midnight Physics::Space Physics 0103 physical sciences General Earth and Planetary Sciences Environmental science Arecibo Observatory Ionosphere 010303 astronomy & astrophysics Physics::Atmospheric and Oceanic Physics 0105 earth and related environmental sciences |
| Zdroj: | Advances in Space Research. 61:1850-1857 |
| ISSN: | 0273-1177 |
| Popis: | Electron concentration (Ne) inferred from Incoherent Scatter Radar (ISR) measurements has been used to determine the influence of solar flux and geomagnetic activity in the ionospheric E-region over Arecibo Observatory (AO). The approach is based on the determination of column integrated Ne, referred to as E-region total electron content (ErTEC) between 80 and 150 km altitude regions. The results discussed in this work are for the AO nighttime period. The study reveals higher ErTEC values during the low solar flux periods for all the seasons except for summer period. It is found that the E-region column abundance is higher in equinox periods than in the winter for low solar activity conditions. The column integrated Ne during the post-sunset/pre-sunrise periods always exceeds the midnight minima, independent of season or solar activity. This behavior has been attributed to the variations in the coupling processes from the F-region. The response of ErTEC to the geomagnetic variability is also examined for different solar flux conditions and seasons. During high solar flux periods, changes in Kp cause an ErTEC increase in summer and equinox, while producing a negative storm-like effect during the winter. Variations in ErTEC due to geomagnetic activity during low solar flux periods produce maximum variability in the E-region during equinox periods, while resulting in an increase/decrease in ErTEC before local midnight during the winter/summer periods, respectively. |
| Databáze: | OpenAIRE |
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