Evaluation of commercial GNSS radio occultation ionosphere and space weather data products using COSMIC-2

The UCAR COSMIC is the partner of the U.S. National Oceanic and Atmospheric Administration Commercial Weather Data Pilot program. For the space weather element of this program, the COSMIC CDAAC processed commercial RO observations from two vendors - PlanetiQ and Spire. This study assesses two ionospheric data products derived from commercial missions’ observations. Our study involved a statistical analysis of the residuals between colocated electron density profiles (EDPs) from reference COSMIC-2 and commercial missions, focusing on F2 layer peak parameters. The analysis of EDP products derived from PlanetiQ and Spire missions’ data shows reasonable agreement with the reference COSMIC-2 EDPs for F2 layer peak parameters, with statistical characteristics similar to ones obtained for COSMIC-2 profile validation against the benchmark ground-based ionosonde observations. The accuracy of absolute Total Electron Content (aTEC) product was evaluated by comparing colocated observations from COSMIC-2 and from commercial satellites. The distributions of aTEC values derived from PlanetiQ and Spire observations demonstrate good overall performance. The errors in absolute slant TEC product derived from commercial RO missions’ data were slightly larger than the accuracy of COSMIC-2 aTEC product, but these ionospheric observations can be valuable data for users. GNSS RO ionospheric observations from the Spire and PlanetiQ commercial satellites at higher latitudes can be a useful data source, complementing the COSMIC-2 low-inclination constellation, for example for global ionosphere climatological research or data assimilation.