Updated Climatological Model Predictions of Ionospheric and HF Propagation Parameters,
NAVAL RESEARCH LAB WASHINGTON DC
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Several climatological models predict ionospheric parameters. A few also predict HF circuit parameters, such as the maximum usable frequency MUF. Using conventional sunspot number inputs, we compare ICED, RADARC, and IONCAP model prediction performance for the F2 layer critical frequency foF2. Monthly median, 5-day average, and daily sunspot numbers, which are based on the 10.7 cm. solar flux, are used for this purpose, along with the ICED effective sunspot number. Relating prediction points to ionosonde data of comparable corrected geomagnetic latitude, in conjunction with an effective sunspot number, improves prediction accuracy. Near-real-time NRT updates of an ionospheric model from observations at a single station is found to dramatically improve predictions of foF2 out to distances of thousands of kilometers, as compared with the use of a global sunspot number. Similar performance for other ionospheric and HF circuit parameters is indicated. For the purpose of NRT predictions of the entire electron density profile the use of two distinct sunspot numbers for the bottomside, coupled with one or more parameters for the topside, is suggested for model updates from a single station.
- Radiofrequency Wave Propagation
- Atmospheric Physics