The study of eclipse effects in D region based on MF radar measurement

In this study, on the basis of the data on 22 July, 2009 derived from MF radar at Kunming station(25. 6 degrees N,103. 8 degrees E), we investigated the response of electron density in the D region to the solar eclipse. Simulated results show that the electron density of D region gradually decreases as the solar eclipse begins and increases slowly after the mid eclipse. However, the change in electron density is not in accord with the solar eclipse processes, and there is an about 9-minute time delay from the moment of mid eclipse to the moment of minimum electron density. An attempt to establish two simple models is proposed to estimate the effective recombination coefficients of D region using the data during the solar eclipse. The model results retain good correspondence with previous theoretical investigations and measurements, and the second model is a better way to calculate the effective recombination coefficients of D region than the first model.