• ionosphere;
  • GPS;
  • Abel transform

[1] In June 2006 an early opportunity arose to compare occultation-based electron density profiles with incoherent scatter radar data. The former were made available by the constellation of satellites called COSMIC. We find that the value of the peak plasma density in the F region is reasonably well characterized but that the altitude of the peak is overestimated above about 300 km and underestimated below that height. A simple Abel transform is not suitable for determining the E region profiles, even in daytime. We also compared the emission strength recorded by the Tiny Ionospheric Photometer (TIP) on board COSMIC to the Arecibo measurement of the TEC as part of an ongoing effort to calibrate the former. The TIP and Arecibo data both show the development of an ionospheric storm of the type referred to as high-intensity, long-duration continuous AE activity. It is surprising that such a modest magnetic storm (Dst ∼ −2.5 nT) resulted in the anomaly moving to nearly 30° magnetic latitude.