What to Do When the F10.7 Goes Out?

Elvidge, Sean; Themens, David R.; Brown, Matthew K.; Donegan‐Lawley, Elizabeth

doi:10.1029/2022sw003392

Cited by 3 publications

(2 citation statements)

References 35 publications

(52 reference statements)

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“…The solar radio flux at 10.7 cm wavelength is an important parameter to characterize the level of solar activity, which is called the solar F10.7 index in "solar flux units" (SFU) [65]. Because of the strong correlation between F10.7 and solar EUV radiation, F10.7 is often used as a proxy for solar UV/EUV (SAT et al, 2023 [66]).…”

Section: Solar and Geomagnetic Indicesmentioning

confidence: 99%

Evaluation of TIEGCM based on GOCE neutral density

Li,

Shao,

Wang

et al. 2024

Front. Phys.

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The Thermosphere Ionosphere Electrodynamic General Circulation Model (TIEGCM), as one of the most advanced physical models of the Earth’s thermosphere and ionosphere, is not only widely used in scientific research, but also has essential reference value in aerospace operations. In this study, we use Gravity field and steady-state Ocean Circulation Explorer (GOCE) neutral density to evaluate the accuracy of the TIEGCM. The assessment is performed on both time and spatial scales. The time scales are conducted annually, monthly, and daily, while the spatial scales are carried out in terms of altitude, latitude, and local time. On the time scales, the performance of the TIEGCM on the monthly time scale is better than that on the annual time scale. Also, the performance on the daily time scale is better than that on the monthly time scale. The relative deviation shows a significant seasonal variation, that is, larger in winter and summer and smaller in spring and autumn. In addition, the relative deviation shows a negative correlation with F10.7 and Ap. On the spatial scale, with the increase in altitude, the average relative deviation of the model becomes larger in general. The relative deviation is usually larger at middle latitudes in the Northern Hemisphere and high latitudes in the Southern Hemisphere. Finally, on the scale of local time, the relative deviation changes more dramatically in local morning than at dusk.

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Section: Solar and Geomagnetic Indicesmentioning

confidence: 99%

Evaluation of TIEGCM based on GOCE neutral density

Li,

Shao,

Wang

et al. 2024

Front. Phys.

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“…These limitations have led to observed discrepancies in model performance when using different indices, especially when representing TEC (Tariku, 2019). More significantly, in the context of blackouts in solar proxies, it is possible to reconstruct those proxies for operational usage using solar radio measurements in neighboring wavelengths (Elvidge et al, 2023), which provides additional robustness for space situational awareness, but exacerbates the effects of the already inherent limitations of the index due to imperfect reconstruction.…”

Section: Introductionmentioning

confidence: 99%

On Generalized Additive Models for Representation of Solar EUV Irradiance

Brandt,

Vega,

Ridley

2024

Space Weather

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In the context of space weather forecasting, solar EUV irradiance specification is needed on multiple time scales, with associated uncertainty quantification for determining the accuracy of downstream parameters. Empirical models of irradiance often rely on parametric fits between irradiance in several bands and various solar indices. We build upon these empirical models by using Generalized Additive Models (GAMs) to represent solar irradiance. We apply the GAM approach in two steps: (a) A GAM is fitted between FISM2 irradiance and solar indices F10.7, Revised Sunspot Number, and the Lyman‐α solar index. (b) A second GAM is fit to model the residuals of the first GAM with respect to FISM2 irradiance. We evaluate the performance of this approach during Solar Cycle 24 using GAMs driven by known solar indices as well as those forecasted 3 days ahead with an autoregressive modeling approach. We demonstrate negligible dependence of performance on solar cycle and season, and we assess the efficacy of the GAM approach across different wavelengths.

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