Simultaneous observations of radio wave phase and intensity variations for locating the plasma layers in the ionosphere

A new method is introduced to locate the layered structures in the ionosphere based on simultaneous observations of radio wave temporal intensity and phase variations in trans-ionospheric satellite-to-satellite links. The method determines location of the tangent point on the trans-ionospheric ray trajectory where gradient of refractivity is perpendicular to the ray trajectory and the influence of a layered structure on radio wave parameters is maximal. This new technique was applied to the measurements provided during CHAMP radio occultation (RO) mission. For the considered RO events, the locations of the inclined plasma layers in the lower ionosphere are found and the electron density distributions are retrieved. The method is checked by measuring the location of the tangent point on the ray trajectory in the neutral gas in the atmosphere. The results showed a fairly good agreement.