27-day fluctuations in the ionospheric D-region.
Abstract
The 27-day fluctuations in ionospheric absorption of radio waves along three radio paths in Central and Southeastern Europe are investigated over the interval 1982-1988 together with analogous fluctuations in the solar Lyman-α flux and in the prevailing wind in the lower thermosphere. The 27-day fluctuations in the lower ionosphere are of direct solar origin only if the Lyman-α flux exhibits a very well expressed solar rotation variation. The absorption fluctuations are largest in winter near solar activity minimum, in fair coincidence with the maxima of corresponding fluctuations in zonal and particularly meridional winds. This indicates a dynamical forcing (maybe of solar origin).
- Publication:
-
Journal of Atmospheric and Terrestrial Physics
- Pub Date:
- December 1991
- DOI:
- 10.1016/0021-9169(91)90064-E
- Bibcode:
- 1991JATP...53.1145P
- Keywords:
-
- D Region;
- Ionospheric Propagation;
- Radio Attenuation;
- Solar Rotation;
- Solar Terrestrial Interactions;
- Thermosphere;
- Twenty-Seven Day Variation;
- Lyman Alpha Radiation;
- Meridional Flow;
- Solar Activity Effects;
- Zonal Flow (Meteorology);
- Earth Ionosphere: Fluctuations;
- Earth Ionosphere: Solar Extreme UV;
- Earth Ionosphere: Solar Activity