A New Method to Retrieve Thermospheric Parameters From Daytime Bottom‐Side Ne(h) Observations

Abstract

A new method to extract neutral composition (O, O2, N2), exospheric temperature Tex, vertical plasma drift, W, and the total solar Extreme Ultraviolet flux with λ ≤ 1050 Å from routine ionosonde bottom‐side electron density, Ne(h), observations has been proposed. The method can be used around noontime hours for all months of the year at middle latitudes where the ionospheric F‐layer is formed by solar Extreme Ultraviolet radiation. The uncertainty of the retrieved neutral gas density coincides with the announced Mean Relative Deviation ±(10‐15%) of CHAMP/STAR neutral gas density observations. The method also provides statistically significant better results in a comparison with modern Mass‐Spectrometer‐Incoherent‐Scatter, Jacchia‐Bowman 2008, and Drag Temperature Model 2013 empirical models. The thermospheric parameters retrieved for the St. Patrick Day magnetic storm and two so‐called Q‐disturbance periods are given as an example of the method application. The retrieved neutral gas densities for the St. Patrick Day storm are compared to Swarm‐B accelerometer observations. The proposed method may be considered as a useful tool for analyses of the state of the upper atmosphere under various geophysical conditions.

Poststorm Thermospheric NO Overcooling?

“…Therefore, fitting observed ρ, N m F 2 , and five values of electron concentration at F 1 -region heights in accordance with our method (Perrone & Mikhailov, 2018) we obtain a complete and consistent set of the main aeronomic parameters necessary to analyze the problem of poststorm neutral gas density variations. Electron concentration N m F 2 depends on the intensity of solar EUV radiation, neutral composition (O, O 2 , N 2 ), temperature Tex, and on vertical plasma drift mainly related to thermospheric winds.…”

“…Neutral gas density at a fixed height of a satellite also depends on (O, O 2 , N 2 ) and temperature Tex. Therefore, fitting observed ρ, N m F 2 , and five values of electron concentration at F 1 -region heights in accordance with our method (Perrone & Mikhailov, 2018) we obtain a complete and consistent set of the main aeronomic parameters necessary to analyze the problem of poststorm neutral gas density variations.…”

“…Our method (Perrone & Mikhailov, 2018) has a version using f o F 1 instead of plasma frequency at 180 km, f o180 , and this version may be used in summer when f o F 1 observations are available. Our method (Perrone & Mikhailov, 2018) has a version using f o F 1 instead of plasma frequency at 180 km, f o180 , and this version may be used in summer when f o F 1 observations are available.…”

“…Our method (Perrone & Mikhailov, 2018) including the observed neutral gas density as a fitted parameter was applied to ionospheric observations at the two stations and the inferred aeronomic parameters are given in Tables 4 and 5. MSISE00 fails to reproduce ρ variations (Tables 4 and 5) for such supper storm conditions and this is explainable.…”

“…Unfortunately DPS-4 Ne(h) observations are absent for some days during the period in question both at Juliusruh and Rome and available manually scaled f o F 1 data were requested directly from the ionosondes. Our method (Perrone & Mikhailov, 2018) has a version using f o F 1 instead of plasma frequency at 180 km, f o180 , and this version may be used in summer when f o F 1 observations are available. CHAMP/STAR neutral gas density observations were used in the retrieval process as this was mentioned earlier.…”