Relation between daytime and nighttime values of the critical frequency f_oF2

Abstract

[1]  The effect detected earlier by L. B. Vanina and A. D. Danilov (2003) is discussed in detail. The effect is that a high enough and statistically significant negative correlation coefficient is observed between the near-noon and near-midnight values of the critical frequency f_oF2. In this paper, the peculiarities of the effect (dependence on season, solar and geomagnetic activity, and geomagnetic latitude) are considered in detail on the basis of the data of a few ionospheric stations located in various geographic zones.

Received 6 December 2005; revised 18 May 2006; accepted 17 August 2006; published 28 November 2006.

Keywords: Critical frequency; Day-to-night ratio; Seasonal variation.

Index Terms: 2499 Ionosphere: General or miscellaneous; 2443 Ionosphere: Midlatitude ionosphere; 2427 Ionosphere: Ionosphere/atmosphere interactions.