Ionospheric Response to Solar EUV Radiation Variations:
Comparison based on CTIPe Model Simulations and Satellite
Measurements

Vaishnav, Rajesh; Schmölter, Erik; Jacobi, Ch.; Berdermann, Jens; Codrescu, M.

doi:10.5194/angeo-2020-83

Cited by 2 publications

(4 citation statements)

References 37 publications

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“…Furthermore, no improvements are expected with respect to the use of solar EUV data with TIE-GCM because of the variations in the measured spectrum and the uncertainties of the cross-sections applied, which are larger than the uncertainties of the F10.7-based modeling approach (Solomon, 2005). The analysis and discussion of the influence of different solar EUV spectra or proxies were done by other studies (Vaishnav et al, 2020) and are not part of this work. F10.7 is a commonly used index describing the solar activity at a wavelength of 10.7 cm.…”

Section: Solar Radio Flux Index F107mentioning

confidence: 99%

“…The delay was studied with the Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics Model (CTIPe) by Vaishnav et al. (2018, 2020, 2021) to analyze the features of temporal and spatial variations, the response to different solar activity and the role of the eddy diffusion. Vaishnav et al.…”

Section: Introductionmentioning

confidence: 99%

“…Recent studies investigated the delayed ionospheric response with upper atmosphere models to improve the understanding of the underlying processes. The delay was studied with the Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics Model (CTIPe) by Vaishnav et al (2018Vaishnav et al ( , 2020Vaishnav et al ( , 2021 to analyze the features of temporal and spatial variations, the response to different solar activity and the role of the eddy diffusion. Vaishnav et al (2021) confirmed and discussed the increase of the delayed ionospheric response with increasing solar activity, which was indicated in analysis based on observations by .…”

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confidence: 99%

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The Height‐Dependent Delayed Ionospheric Response to Solar EUV

et al. 2022

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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+ ${\mathrm{O}}_{2}^{+}$ 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.

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Section: Solar Radio Flux Index F107mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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The Height‐Dependent Delayed Ionospheric Response to Solar EUV

et al. 2022

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“…GUVI O / N 2 data are available at: http://guvitimed.jhuapl.edu/data/products (NASA, 2022e). The CTIPe simulation data used for this work can be accessed at https://doi.org/10.5281/zenodo.8145356 (Vaishnav, 2023).…”

Section: Data Availability Statementmentioning

confidence: 99%

Ionospheric Response to Solar EUV Radiation Variations Using GOLD Observations and the CTIPe Model

Vaishnav,

Jacobi,

Berdermann

et al. 2023

JGR Space Physics

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To understand the global response of thermospheric‐ionospheric (TI) parameters to variations in solar irradiance measurements from the Global‐Scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph, solar radio flux F10.7, predictions from the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) model, and International Global Navigation Satellite System Service total electron content maps (TEC) have been used. Various parameters such as GOLD O/N2, O2, and the nighttime peak electron density (Nmax) have been compared with the CTIPe model simulations. The GOLD observed Nmax shows a number of significant features including a winter anomaly and an equatorial ionization anomaly. The comparison with solar proxies showed that the GOLD QEUV correlates very well with the EUV observations compared to the F10.7 index. The study also examined the relationship between the solar proxies and Nmax on different time scales and found that Nmax responded significantly to QEUV at both medium‐ and long‐term timescales. Furthermore, a low correlation between Nmax in the equatorial region and solar proxies was found. A delayed ionospheric TEC response against solar flux variations within the 27‐day solar rotation was investigated. This ionospheric delay of TEC with respect to solar flux was observed to be less than 1 day, which was reproduced in model simulations. The current study has shown that the GOLD observations can be used to investigate the delayed ionospheric response and to gain a better understanding of the influence of solar activity on the TI system.

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Ionospheric Response to Solar EUV Radiation Variations: Comparison based on CTIPe Model Simulations and Satellite Measurements

Cited by 2 publications

References 37 publications

The Height‐Dependent Delayed Ionospheric Response to Solar EUV

The Height‐Dependent Delayed Ionospheric Response to Solar EUV

Ionospheric Response to Solar EUV Radiation Variations Using GOLD Observations and the CTIPe Model

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