Comparison between ionospheric peak parameters retrieved from COSMIC measurement and ionosonde observation over Sanya

In this paper we compared the ionospheric peak parameters (peak electron density of the F region, NmF2, and peak height of the F region, hmF2) retrieved from the FORMASAT-3/COSMIC (COSMIC for short) satellite measurement with those from ionosonde observation at Sanya (18.3°N, 109.6°E) during the period of 2008-2013. Although COSMIC NmF2 (hmF2) tends to be lower (higher) than ionosonde NmF2 (hmF2), the results show that the ionospheric peak parameters retrieved from COSMIC measurement generally agree well with ionosonde observation. For NmF2 the correlation between the COSMIC measurement and the ionosonde observation is higher than 0.89, and for hmF2 the correlation is higher than 0.80. The correlation of the ionospheric peak parameters decreases when solar activity increases. The performance of COSMIC measurement is acceptable under geomagnetic disturbed condition. The correlation of NmF2 between COSMIC and ionosonde measurements is higher (lower) during the nighttime (daytime), while the correlation of hmF2 is lower (higher) during the nighttime (daytime).