Hysteresis of <i>fo</i>F2 at European middle latitudes
The hysteresis of <i>f</i>oF2 is studied for several European stations over the whole 24-hour diurnal interval for the equinoctial months of the years just before and just after the solar cycle minimum for solar cycles 20 and 21. Based on previous results, the hysteresis is expected...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2000-08-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/18/987/2000/angeo-18-987-2000.pdf |
| Summary: | The hysteresis of <i>f</i>oF2 is studied for
several European stations over the whole 24-hour diurnal interval for the
equinoctial months of the years just before and just after the solar cycle
minimum for solar cycles 20 and 21. Based on previous results, the hysteresis is
expected to develop best just for the equinoctial months and near the solar
cycle minimum. The hysteresis is generally found to be negative, i.e. higher <i>f</i>oF2
for the rising branch compared to the falling branch of solar cycle. However,
this is not the case in some individual months of some years. The noontime
hysteresis represents the hysteresis at other times of the day qualitatively (as
to sign) but not quantitatively. The hysteresis appears to be relatively
persistent from one solar cycle to another solar cycle in spring but not in
autumn. A typical value for springtime hysteresis is about 0.5 MHz. The
inclusion of hysteresis into long-term ionospheric and radio wave propagation
predictions remains questionable.<br><br><b>Key words: </b>Ionosphere
(mid-latitude ionosphere; ionospheric disturbances) |
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| ISSN: | 0992-7689 1432-0576 |