Solar cycle length variation: its relation with ionospheric parameters
Abstract
It is established that ionospheric parameters are linearly related to the sunspot number, R2, and the solar flux at 2800 MHz, F10.7. These solar activity parameters provide a measure of the EUV radiation variability which is responsible for most of the ionospheric ionization. Based on evidences that Northern Hemisphere land air temperature anomaly correlates with solar cycle length, SCL, a solar activity parameter of long-term change, and that this parameter is a measure of solar irradiance variability, it can be expected that there is some effect on the ionospheric electron density. If there exist changes in solar energy shown by solar cycle length variation, these could be observed better in ionospheric data. In this paper it is shown that the ionospheric electron density anomaly measured around 400 km, NmaxA, follows the solar cycle length variation in the period 1949-1992 as the Northern Hemisphere land air temperature anomaly does. This result shows that Nmax varies not only with Rz or F10.7 but also with SCL. SCL seems to be a good indicator of long term changes in the EUV solar radiation which affects the ionosphere.
- Publication:
-
Journal of Atmospheric and Solar-Terrestrial Physics
- Pub Date:
- January 1997
- DOI:
- 10.1016/S1364-6826(96)00056-9
- Bibcode:
- 1997JASTP..59..159D