Hemispherical F2-layer differences and the neutral atmosphere
Abstract
The paper describes a study of noon and early morning (05 h) critical frequencies of the F2-layer through one solar cycle (1958-1969) at eight pairs of dip-conjugate stations at latitudes lower than plus or minus 60 deg dip. At sunspot minimum the noon foF2 values exhibit a marked semiannual variation with equinoxial maxima in the north and a dominant annual variation with a maximum in December in the south. The annual component of the foF2 variations increases appreciably with solar activity in the north, while the semiannual component increases in the south. The geographically symmetrical, global meridional neutral winds and seasonal changes in atmospheric composition are suggested as the cause of the differences in the seasonal variation of F2 ionization at dip-conjugate stations.
- Publication:
-
Journal of Atmospheric and Terrestrial Physics
- Pub Date:
- May 1978
- DOI:
- 10.1016/0021-9169(78)90101-0
- Bibcode:
- 1978JATP...40..623K
- Keywords:
-
- Annual Variations;
- Atmospheric Composition;
- Critical Frequencies;
- Diurnal Variations;
- F 2 Region;
- Solar Activity Effects;
- Hemispheres;
- Ionospheric Propagation;
- Meridional Flow;
- Neutral Gases;
- Solar Cycles;
- Sunspots