Artificial ionospheric Wave Number 4 structure below the F2 region due to the Abel retrieval of radio occultation measurements

The Abel-retrieved electron density from both the F-3/C observations and the simulated results by an empirical model with an imposed WN4 structure in the F layer are investigated. It is found that the Abel inversion can reproduce the real WN4 structure well in the F2 layer.

However, it will result in pseudo and reversed phase WN4 structure in the lower altitude (F1 and E layers). Quantitatively, relative ±15% WN4 signature in the F2 layer can produce ±40% artificial WN4 in the E and F1 layers. Analysis on the F-3/C data shows about ±15% WN4 signature in the F2 layer and ±50% WN4 with reversed-phase in the E and F1 layers.