Are models predicting a realistic picture of vertical total electron content?
Article first published online: 5 FEB 2004
Copyright 2004 by the American Geophysical Union.
Volume 39, Issue 1, February 2004
How to Cite
2004), Are models predicting a realistic picture of vertical total electron content? Radio Sci., 39, RS1S14, doi:10.1029/2002RS002823., , , and (
- Issue published online: 5 FEB 2004
- Article first published online: 5 FEB 2004
- Manuscript Accepted: 26 NOV 2003
- Manuscript Revised: 21 SEP 2003
- Manuscript Received: 13 NOV 2002
- ionospheric models;
- vertical total electron content;
- slant total electron content;
- global ionosphere maps
 The present work analyzes results coming from global maps of ionospheric total electron content (TEC) obtained from observations and from different empirical models like the International Reference Ionosphere (IRI), the model family developed at Trieste and Graz (NeQuick, COSTprof, and NeUoG-plas), and the GPS operational model (formulation by J. A. Klobuchar). Since they still appear in the context of assessment studies we have also included “old” models like the Bent model. The attention is focused on situations which occurred in the present period of high solar activity, pointing out features like the equatorial anomaly and polar regions, which are crucial test regions for ionospheric TEC models. Experimental estimates of slant TEC from International GPS Service (IGS) stations have been compared particularly with the predictions of the NeQuick and GPS models. A very simple picture of the ionosphere like the one given by the GPS operational model appears to be insufficient to reproduce the global complex behavior of the ionosphere, as it is needed for assessment studies or for modern operational real-time corrections of transionospheric propagation errors. The IRI estimates of TEC still present serious problems, essentially owing to the topside under high solar activity conditions, and the model cannot be integrated to heights above 2000 km. With processing resources suitable for real-time operation, it seems that the NeQuick model can give a more widely reliable picture of the TEC estimated from GPS measurements. Computing times for this model are considerably smaller than for more complex models like NeUoG-plas.