The 10.7-cm Solar Flux and the 26-Month Oscillation

Abstract

The 10.7-cm solar radio flux is considered to be highly correlated with solar extreme ultraviolet radiation, thermospheric temperatures, sunspots, and the 27-day and 11-year solar cycles. To investigate the possibility of ultraviolet radiation being a cause of the quasi-biennial oscillation in tropical stratospheric winds and temperatures, the daily values of 10.7-cm flux were subjected to a non-linear, curve-fitting analysis to determine the major component sinusoidal frequencies of the time series. No evidence was found for a period near 26 months; hence, to the extent that extended ultraviolet 10-cm flux relationship is valid, ultraviolet insolation does not appear to vary with a quasi-biennial oscillation.