Time variations of the level of the 27 kHz atmospherics established by FFT-analysis
Abstract
The paper analyzes the level of the 27 kHz atmospherics during 1959-1977 by FFT-analysis. In the FFT-periodgram, the annual period and its first harmonic of 182.04 days are clearly established; also, the twofold and threefold fluctuations of the annula periods of 682.66 and 910.22 days are observed. The autocorrelation coefficients achieve their minimum values during the rising part and solar cycle maximum. It is concluded that at the level of the 27 kHz atmospherics, the periodic variations in the solar and the geomagnetic activity variations strongly influence the variation of the synodic rotation periods.
- Publication:
-
Bulgarsko Geofizichno Spisanie
- Pub Date:
- 1979
- Bibcode:
- 1979BlGSp...5...35C
- Keywords:
-
- Annual Variations;
- Atmospherics;
- Fast Fourier Transformations;
- Periodic Variations;
- Solar Terrestrial Interactions;
- Autocorrelation;
- Magnetic Storms;
- Solar Activity Effects;
- Solar Cycles