Data assimilation retrieval of electron density profiles from radio occultation measurements

The RO data observed by COSMIC satellites on day of year 266 in 2009 are selected to do both the simulation work and the real data retrieval test. The results show that the data assimilation technique can improve the electron density retrieval in comparison with the Abel inversion.

It is less influenced by the ionospheric inhomogeneity than the Abel method. Some pseudo-large-scale features made by the Abel retrieval, such as the plasma cave underneath the equatorial ionization anomaly region and the three peaks along the latitude direction in the E layer, disappear in the data assimilation retrieval results. Independent validation by ground-based ionosonde observations confirms the improvement of data assimilation retrieval below the F2 peak.