Using Lightning-Generated Whistlers for Accurate 3-D Ionospheric Electron Density Inversion

Lightning-generated whistlers (LGWs) carry information about ionospheric electron density due to the dispersion effect in the ionosphere and thus can be utilized as an inexpensive medium to detect the ionosphere. In this article, data assimilation technology is adopted as the ionospheric inversion method based on the relationship between the dispersion of LGWs and ionospheric electron density. Using LGWs observed by the China Seismo-Electromagnetic Satellite (CSES), a 3-D electron density assimilation model is constructed for the central eastern regions and surrounding seas of China. After assimilation, the discrepancy between the vertical total electron content (VTEC) of the background model and the true value is significantly reduced under both quiet and magnetic storm conditions. The root mean square error (RMSE) of VTEC decreases by 56.06% under quiet conditions and 46.81% under magnetic storm conditions. Additionally, the model effectively corrects the electron density profile, improving the F2 layer’s peak electron density accuracy by over 50%. When applied to the summer of 2021, the RMSE of assimilated VTEC decreases to below 3 TECU in all cases. The mean and standard deviation of the RMSE after assimilation are 2.4631 TECU and 0.3048 TECU, respectively, demonstrating the model’s accuracy and stability. The method proposed in this article fills a gap in the research domain of 3-D electron density inversion by LGWs and provides valuable observations for ionospheric regions that are difficult to detect by artificial emission signals.