Extended Analysis of Real‐Time f_oF₂ Mapping in Mideastern China Based On Shortwave Signals

Abstract

A method for the real‐time mapping of the critical frequency of the F2 layer (foF2) is established using shortwave radio signals as the radiation sources, thereby eliminating the need for ionosonde stations, and tested in mideastern China. The ionospheric foF2 in the reflection area between the receiving station and the radio stations is obtained using a probabilistic inversion method. Subsequently, Kriging is used for the real‐time foF2 mapping. To heighten the performance of the reconstruction, the International Reference Ionosphere 2012 (IRI‐2012) Model was used as a background for ionospheric interpolation to calculate regional variant. The mapping accuracy is estimated using ionosonde data derived from seven stations in mideastern China: Xinxiang (35.2°S, 113.9°E), Wuhan (30.6°S, 114.6°E), Qingdao (36.1°S, 12.4°E), Suzhou (30.3°S, 120.6°E), Xian (34.3°S, 108.9°E), Chongqing (29.6°S, 106.5°E), and Guangzhou (23.1°S, 113.3°E). The data were recorded approximately every 15 min during two recording intervals between 04:00 UTC LT on 31 October 2012, and 03:30 UTC on 1 November 2012. The estimates of foF2 obtained from the reconstruction method and the foF2 values predicted using IRI are compared with the measurements from the vertical ionosondes at the above seven stations. The root‐mean‐square error and percent deviation are calculated to evaluate the performance of the inversion model. The results indicate that the new method for real‐time foF2 mapping based on shortwave signals is a promising candidate technique for obtaining ionospheric parameters and studying the ionosphere.