Long-term Measurements of Nighttime LF Radio Wave Reflection Heights over Central Europe
The nighttime ionospheric absolute reflection height of low-frequency (LF) radio waves at oblique incidence has been measured continuously since late 1982 using 1.8kHz sideband phase comparisons between the sky wave and the ground wave of a commercial 177kHz LF transmitter. The dataset allo...
| Main Authors: | , |
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| Format: | Article |
| Language: | deu |
| Published: |
Copernicus Publications
2005-01-01
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| Series: | Advances in Radio Science |
| Online Access: | http://www.adv-radio-sci.net/3/427/2005/ars-3-427-2005.pdf |
| Summary: | The nighttime ionospheric absolute reflection height of low-frequency (LF) radio waves at oblique incidence has been measured continuously since late 1982 using 1.8kHz sideband phase comparisons between the sky wave and the ground wave of a commercial 177kHz LF transmitter. The dataset allows the analysis of long-term trends and other regular variations of the reflection height. Beside the clear signal of the 11-year solar cycle a quasi-biennial oscillation is visible in LF reflection heights, which is correlated to the equatorial stratospheric wind field. A long-term decreasing reflection height trend is found, confirming results from other measurements and theoretical estimations. The results can be interpreted as a long-term decrease of the height levels of fixed electron density in the lower E region, reflecting a long-term cooling trend of the middle atmosphere. |
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| ISSN: | 1684-9965 1684-9973 |