Global simulations of multi-frequency hf signal absorption for direct observation of middle atmosphere temperature and composition
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley
Abstract
This paper presents the first numerical study on a new concept for the direct measurement of
D-region absorption in the high-frequency (HF) band. Numerical simulations based on the Appleton-Hartree
and Garrett equations of refractive index are presented. Electron temperature as a result of HF radio pumping of
the ionosphere is included in the calculations using proper numerical formulation. Both O- and X-mode radio
wave polarizations are taken into consideration. A global map of HF absorption in the northern hemisphere is
calculated. Detailed calculations of HF radio wave absorption as it propagates through the lower atmosphere are
presented. The effect of several parameters on the amount of absorption is calculated. The best frequencies to
be used for the purpose of this study are discussed. A machine learning model is developed and the capability
of the model in estimation of D and E-region constituents includes N2, O, O2, as well as T and Ne is examined.
Such a technique can also lead to global mapping of HF absorption and improve OTHR (over-the-horizonradar)
performance.
Description
Keywords
Physics, Astronomy, Geography, High-frequency
Citation
Mahmoudian, A. et al. (2023). Global simulations of multi-frequency hf signal absorption for direct observation of middle atmosphere temperature and composition. Journal of Geophysical Research, 128(2), e2022JA030930. https://doi. org/10.1029/2022JA030930