Observation of Ionospheric Effects in the Polar Ionosphere using GPS-Radio Occultation and EISCAT Data

Abstract

We present observations of the polar ionosphere obtained by combining radio occultation data from the CHAMP, GRACE, and COSMIC/Formosat-3 satellite missions and EISCAT data collected during the IPY. The large amount of data which is being collected during the IPY is an excellent data source for comparing the radio occultation method with the independent EISCAT measurements with high statistics. For the winter period 2006-07 we have found that in the northern polar ionosphere electron density profiles showing enhanced E-layer ionization occur with a probability exceeding 80% during the local morning hours and closely follow the Auroral Oval. We use the EISCAT in order to verify these observations obtained by the radio occultation method and to get more insight into the physics of this phenomenon. Furthermore, the comparison is used to validate electron density profiles retrieved from GPS radio occultation measurements onboard CHAMP.