An empirical modeling of the D region ionosphere based on [formula omitted].

• The electron density in the D region obtained by Kunming (25.6N,103.8E) MF radar is used in this study. • The strong positive correlation of electron density in the D region with solar activity. • A empirical model of D region is established based on the correlation between D ionosphere and F107. The electron density (N e) in the D region, although its value is much smaller than that in the F region, has a highly important effect on electromagnetic wave propagation by energy absorption due to high-frequency collisions between electron-molecular, electron-ionic, molecular-ionic and so on. Solar activity is the main source of ionization in the D region of the ionosphere. The observed N e during 2008–2015 by the Kunming station (25.6°N, 103.8°E) medium radar (MF radar) is utilized to analyze its strong relationship with solar activity. Then, the relationship between them is employed to establish an empirical model in this study. The N e in the D region is enhanced with increasing height and time towards noon, and the solar zenith angle is increasingly smaller towards noon. The averages of N e at several heights below and above 76 km show that the D region ionosphere up to 76 km is more strongly controlled by solar radiation and less strongly controlled below 76 km. According to the above, an empirical model is established based on the relationship between the D-region ionosphere and solar activity index F 107. [ABSTRACT FROM AUTHOR]