• Ionospheric model;
  • M(3000)F2;
  • modeling technique;
  • EOF

[1] An empirical orthogonal function (EOF) analysis, combined with a regression analysis, is conducted to construct an empirical model for the ionospheric propagation factor M(3000)F2. First, a single station model is constructed using monthly median hourly values of M(3000)F2 data observed at Wuhan Ionospheric Observatory (geographic 114.4°E, 30.6°N; 45.2°dip) during the years of 1957–1991 for demonstrating the modeling technique based on EOF expansion and regression analysis of the EOF coefficients. The constructed climatological model incorporates the diurnal, seasonal as well as solar-cycle variations of M(3000)F2. A comparison between the observational results and the modeled ones showed good agreement. Then, an attempt is made to model global M(3000)F2 data using data from stations distributed around the world. Our preliminary result showed that the modeling technique based on EOF expansion, which is combined with regression analysis of the EOF coefficients as described in this paper, is very promising when used in global modeling and is worthwhile to investigate further.