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Role of eddy diffusion in the delayed ionospheric response to solar flux changes
- Source :
- Annales Geophysicae, Vol 39, Pp 641-655 (2021)
- Publication Year :
- 2021
- Publisher :
- Copernicus GmbH, 2021.
-
Abstract
- Simulations of the ionospheric response to solar flux changes driven by the 27 d solar rotation have been performed using the global 3-D Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) physics-based numerical model. Using the F10.7 index as a proxy for solar extreme ultraviolet (EUV) variations in the model, the ionospheric delay at the solar rotation period is well reproduced and amounts to about 1 d, which is consistent with satellite and in situ measurements. From mechanistic CTIPe studies with reduced and increased eddy diffusion, we conclude that the eddy diffusion is an important factor that influences the delay of the ionospheric total electron content (TEC). We observed that the peak response time of the atomic oxygen to molecular nitrogen ratio to the solar EUV flux changes quickly during the increased eddy diffusion compared with weaker eddy diffusion. These results suggest that an increase in the eddy diffusion leads to faster transport processes and an increased loss rate, resulting in a decrease in the ionospheric time delay. Furthermore, we found that an increase in solar activity leads to an enhanced ionospheric delay. At low latitudes, the influence of solar activity is stronger because EUV radiation drives ionization processes that lead to compositional changes. Therefore, the combined effect of eddy diffusion and solar activity leads to a longer delay in the low-latitude and midlatitude region.
- Subjects :
- Atmospheric Science
Materials science
010504 meteorology & atmospheric sciences
Science
QC1-999
TEC
Geophysics. Cosmic physics
Flux
Plasmasphere
01 natural sciences
Physics::Geophysics
Eddy diffusion
0103 physical sciences
Earth and Planetary Sciences (miscellaneous)
Astrophysics::Solar and Stellar Astrophysics
Ionosphere
010303 astronomy & astrophysics
0105 earth and related environmental sciences
QC801-809
Physics
Modeling
Geology
Astronomy and Astrophysics
Computational physics
Space and Planetary Science
Extreme ultraviolet
Physics::Space Physics
Solar rotation
Astrophysics::Earth and Planetary Astrophysics
Thermosphere
Solar EUV
Subjects
Details
- ISSN :
- 14320576
- Volume :
- 39
- Database :
- OpenAIRE
- Journal :
- Annales Geophysicae
- Accession number :
- edsair.doi.dedup.....64064e5e8ef978c8b4625b479ae0260c