Ingestion of Radio Occultation Data for Ionospheric Data Assimilation

Radio Occultation (RO) data is one of the most important data sources for many Ionospheric Data Assimilation schemes. For example, COSMIC-2 RO data has dense coverage of the low and mid-latitude regions of the ionosphere. It is usually believed that it is better to ingest raw data into data assimilation scheme and to minimize data pre-processing, therefore, schemes like IDA4D ingest slant total electron content (sTEC) RO data. This study demonstrates that better results can be achieved by

performing Abel inversion to invert electron density along tangent points and then ingesting these point density measurements into data assimilation. A 2-D experiment with real RO geometry was performed to directly compare these two methods of data ingestion. The ingestion of Abel inverted point density is able to better retrieve the hmF2 parameter and the structure of the bottom side of the profile in comparison to the direct ingestion of sTEC data, especially when the hmF2 of the truth is below the hmF2 of the background or when the horizontal gradient is present.