Ionospheric local model and climatology from long-term databases of multiple incoherent scatter radars

Empirical ionospheric local models have been developed from long-term data sets of seven incoherent scatter radars spanning invariant latitudes from 25 degrees to 75 degrees in American, European and Asian longitudes at Svalbard, Tromso, Sondrestrom, Millstone Hill, St. Santin, Arecibo and Shigaraki. These models, as important complements to global models, represent electron density, ion and electron temperatures, and ion drifts in the E and F regions, giving a comprehensive quantitative description of ionospheric properties. A case study of annual ionospheric variations in electron density and ion temperature is presented based on some of these models. Clear latitudinal, longitudinal, and altitude dependency of annual and semiannual components are found.