Electron densities determined by the HIRAAS Experiment and comparisons with ionosonde measurements

We present electron density profiles derived by inversion of ultraviolet limb scans made by the High Resolution Airglow and Aurora Spectroscopy (HIRAAS) experiment on the Advanced Research and Global Observing Satellite (ARGOS) . The ultraviolet limb scans were inverted using an iterative algorithm based on discrete inverse theory. We present two comparisons with nearly coincident ionosonde measurements of the F‐region peak density and peak height. Our observations took place on 24 November 1999 when the 10.7 cm radio flux was 181 × 10 −22 Watt m −2 Hz −1 and the daily a p was 21, indicating moderate geomagnetic activity. The retrieved peak electron density and peak height were in good agreeent with the ionosonde measurements, demonstrating the accuracy of the ultraviolet technique for sensing the ionospheric state.