Empirical Modeling Method of the Ionospheric Peak Density (NmF2) using the Ionosonde Data over Far East Asian Region

The peak electron density (NmF2) in the ionospheric F2 region is regarded as an important parameter in predicting HF radio communication environments. As a systematic investigation of NmF2 over the Far East Asia in lower mid-latitude, we derived an empirical model for NmF2 based on long-term data measured at the Anyang (37.4°N, 127.0°E), Kokubunji (35.7°N, 139.5°E), Beijing (40.0°N,116.3°E) digisonde stations. The empirical model consists of a formula with 32 coefficients reflecting diurnal, semi-diurnal, annual, and semi-annual variations depending on the solar activity (F10.7 index) and the geomagnetic activity (Ap index) conditions. In this current study, we focus on identifying the differences and similarities among these empirical models derived from three different ionosonde data measured in the mid-latitude ionosphere. These empirical models are expected to contribute to understanding climatological behavior of the mid-latitude ionosphere in Asian sector. They may also be used as basic prediction of the local ionospheric NmF2 variation for various conditions.