Affiliation:
1. Institute of Applied Geophysics
2. Department of Physics, Moscow State University
Abstract
Trends in the F2-layer critical frequency foF2 are calculated based on the vertical sounding data atJuliusruh station over a period of 1996–2022. Four solar activity indices: Ly-α, MgII, F10.7mon, and Rz wereused. The conclusion drawn previously is confirmed: seasonal (stronger in winter than in summer) and diurnal(stronger in the daytime than at night) variations exist in the foF2 negative trends. It is shown that theresults for the first three indices agree very well, whereas the results using Rz provide slightly different results.It has been found that during the recent 5–7 years, the maximum (winter, daytime) negative trends in foF2became stronger than for the entire considered interval by a factor of 2–3
Publisher
The Russian Academy of Sciences
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