Extracting Exospheric Temperature From Daytime Ionospheric Electron Density Profiles

• Published in: Journal of geophysical research. Space physics 2023-04, Vol.128 (4), p.n/a
• Main Authors: Li, Shaoyang, Ren, Zhipeng, Yue, Xinan, Liu, Libo, Yu, Tingting, Wei, Yong
• Format: Article
• Language: English
• Subjects: Aeronomy; Electron density; Electron density profiles; Empirical models; Incoherent scatter radar; Inverse problems; Ionosphere; Ionospheric electron density; Ionospheric electron density profiles; Ionospheric electrons; Ionospheric observations; Mass spectrometry; Orbit determination; Parameters; Plasma density; Radar; Satellite communications; Scattering; Space weather; Temperature variations; Thermosphere; Thermospheric parameters; Upper thermosphere
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2022JA030988

Given that the ionosphere is strongly determined by the thermosphere and its state depends on thermospheric parameters, we propose a new method to extract exospheric temperature (Tex) from electron density (Ne) profiles based on the relationship between the variations in Tex and Ne profiles established through simulation. Ne profiles and corresponding Tex from the Millstone Hill incoherent scatter radar (ISR) observations are used to test the method. ISR Ne profiles are used for Tex retrieval and ISR Tex is used to make a comparison with Tex calculated by model and retrieved Tex. The results show that the retrieved Tex effectively captures diurnal, anomalous and short‐period variations. The relative deviation between the retrieved–observed Tex is approximately 2%, which is significantly improved compared with the Mass Spectrometer Incoherent Scatter model, especially under disturbed conditions. This result confirms that thermospheric temperature variation can be deduced from ionospheric profiles and our method can be considered a useful tool to obtain Tex from Ne profiles. Plain Language Summary Space weather can affect satellite communications and orbit determination and interfere with ground‐based power grids. Thermosphere/ionosphere forecasting based on simple current and past data offers a feasible solution to reduce the impact of space weather. However, measurements of the thermosphere are not an easy task and thermospheric data is deficient and discontinuous. In contrast, a large amount of continuous ionospheric observations have been accumulated. Furthermore, as a tightly coupled ionosphere/thermosphere system, the thermosphere and the ionosphere are interdependent on structure and variation. Thermospheric parameters such as neutral concentration, compositions, and temperature play a vital role in the production and loss of ionosphere plasma density and have a significant impact on electron density. Conversely, the structure and variation in the ionosphere should contain information about the surrounding thermosphere. Theoretically, thermospheric parameters can be obtained by solving the inverse problem of aeronomy. Since exospheric temperature (Tex) is an important parameter describing the upper thermosphere, we develop a method to retrieve Tex from electron density (Ne) profiles in this work. Subsequently, the Tex module in empirical models can be replaced by our retrieved Tex to obtain other thermospheric parameters. The good performance of the m