Predikce sluneční a geomagnetické aktivity

Vlastislav Feik
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic
e-mail: sunwatch(at)asu.cas.cz
 

Tomas Bayer, RWC Prague 
Institute of Geophysics of the ASCR, Prague
Department of Geomagnetism
Budkov observatory (BDV)
 

Remarks:

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere December 13 - December 19, 2024
Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere – December 12, 2024

The high solar activity in October this year suggests that this may have been the peak of an 11-year cycle. This is not to say that solar activity will not continue to rise. On the contrary, it may well be that the first maximum of the cycle took place in October and that we can look forward to a second maximum. This could take place in 2025 or 2026 at the latest, but it will be followed by a decline.

Solar activity in November was lower and December's is even lower. The expected geomagnetic disturbance, predicted for 29 November, did not take place because the CME did not affect the Earth. However, the almost daily occurrence of moderate solar flares continued and a large flare occurred. It happened on 8 December at around 0906 UT. However, even after this eruption no major geomagnetic disturbance followed and the changes in ionospheric shortwave propagation were rather random.

In December, the Sun is quieter, and large sunspot groups do not occur in its photosphere. The only major active regions we see are to the south of the solar equator, and their area is about half that of those seen in November. However, the active area of AR3917 is slowly getting larger and with it the likelihood of a larger flare is increasing.

The Earth's ionosphere has been repeatedly affected in recent days by increased concentrations of solar-origin free electrons, which, while causing a slight rise in MUF, have been more pronounced in the ionosphere, causing scattering and hence attenuation, which has had a negative effect on the longer shortwave bands.

More meteors are arriving at Earth in these today. The swarm is called the Geminids and most meteors should arrive about December 14. Therefore we can observe more frequent occurrences of the sporadic E layer. In addition to the occurrences of stronger signals on the longer shortwave bands, propagation through ionospheric waveguides is more frequent. The sporadic layer may not only form one of the walls of the waveguide, but also enable its termination. Which is a good chance, for example, for QRP devotees.

 

Poznámka:

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