The Height‐Dependent Delayed Ionospheric Response to Solar EUV
DOI: https://doi.org/10.1029/2021JA030118
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/9980
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/9980
Schmölter, Erik; Heymann, Frank; von Savigny, Christian; Berdermann, Jens, 2022: The Height‐Dependent Delayed Ionospheric Response to Solar EUV. In: Journal of Geophysical Research: Space Physics, Band 127, 3, DOI: 10.1029/2021JA030118.
|
View/
|
Based on the analysis of electron density Ne profiles (Grahamstown ionosonde), a case study of the height‐dependent ionospheric response to two 27‐day solar rotation periods in 2019 is performed. A well‐defined sinusoidal response is observed for the period from 27 April 2019 to 24 May 2019 and reproduced with a Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model simulation. The occurring differences between model and observations as well as the driving physical and chemical processes are discussed based on the height‐dependent variations of Ne and major species. Further simulations with an artificial noise free sinusoidal solar flux input show that the Ne delay is defined by contributions due to accumulation of O+ at the Ne peak (positive delay) and continuous loss of O2+ in the lower ionosphere (negative delay). The neutral parts' 27‐day signatures show stronger phase shifts. The time‐dependent and height‐dependent impact of the processes responsible for the delayed ionospheric response can therefore be described by a joint analysis of the neutral and ionized parts. The return to the initial ionospheric state (and thus the loss of the accumulated O+) is driven by an increase of downward transport in the second half of the 27‐day solar rotation period. For this reason, the neutral vertical winds (upwards and downwards) and their different height‐dependent 27‐day signatures are discussed. Finally, the importance of a wavelength‐dependent analysis, statistical methods (superposed epoch analysis), and coupling with the middle atmosphere is discussed to outline steps for future analysis. Key Points:
A response to solar 27‐day signatures is observed in ionosonde Ne height profiles and successfully reproduced with a Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model simulation.
Height‐dependent variations of the delayed ionospheric response are driven by the respective contributions of O+ and O2+.
Transport processes have a significant impact on the 27‐day signatures of neutral and ionized parts in the upper atmosphere.
Statistik:
View StatisticsCollection
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.