EISCAT Radar Ion-Neutral Collision Frequency Analysis

Theoretical incoherent scatter spectra as function of the standard parameters are fitted to observed lag profiles. Absolute power is calibrated by matching electron density to Dynasonde critical frequency or plasmaline shift. This is the fitting of ion-neutral collision frequency. It is normally calculated from the IRI and MSIS model density and temperature, but fitting can be enabled and is usually performed for a limited altitude region in UHF radar data analysis.