An analysis of ionospheric characteristic parameters retrieved from COSMIC and IRI at Jicamarca during the period of 2007-2013

Abstract

To evaluate comprehensively the performance of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) and the International Reference Ionosphere (IRI), ionospheric characteristic parameters, the F2-peak density NmF2 and the F2-peak height HmF2 from Digisonde over Jicamarca (11.95°S, 76.8°W, 1°N geomagnetic) are compared with data from the COSMIC radio occultation and IRI model during the different solar activity period of 2007—2013 in this study. The correlation of the digisonde observations and COSMIC/IRI measurements is analyzed emphatically, and then ionospheric parameters at Jicamarca being overestimated/underestimated by COSMIC and IRI are further discussed. The results are shown as follows: (1) Both the COSMIC-derived NmF2 and the IRI-derived NmF2 are in good agreement with the digisonde-derived measurements, and the correlation coefficients are more than 0.8. The correlation of the COSMIC-derived NmF2 in the solar minimum is greater than that in the solar maximum, and while the correlation of the IRI-derived NmF2 in the solar minimum is smaller than that in the solar maximum; (2) The HmF2 correlation between COSMIC/IRI and digisonde in spring and autumn is greater than that in summer and winter. Most seasonal and temporal correlation coefficients of COSMIC-derived HmF2 are more than 0.8 and 0.6, respectively. However, the correlation of the IRI-derived HmF2 decreased significantly, especially for the summer season in the solar minimum and dusk segment with a value of less than 0.3; (3) The ionospheric parameters are generally overestimated by COSMIC and IRI in the daytime and while they are underestimated from night to dawn in the solar minimum. Distinct from that in the solar minimum, the NmF2 are overestimated during the post-night (0000 LT—0500 LT) in the solar maximum. The current research could be useful for the ionospheric model improvement as well as data assimilation work based on the IRI model and COSMIC radio occultation data.