# Towards a Real-Time Description of the Ionosphere:
## 10 Conclusions  
In the present paper, we compared the IRI and IRTAM models; the latter, being a real-time version of IRI, is based on the assimilation of ionosonde measurements. In order to assess the performance of the two models, two different datasets have been considered: (1) _fo_F2 and _hm_F2 from ground-based ionosonde observations; (2) _fo_F2 and _hm_F2 from space-based COSMIC RO observations. Through different analyses and comparison methodologies, we highlighted the main performances exhibited by both IRI and IRTAM for different locations and under different diurnal, seasonal, solar and magnetic activity conditions.  
The main results of the study are:  
* When ionosonde observations are considered for validation, IRTAM improves significantly the IRI _fo_F2 modeling while it slightly improves the IRI _hm_F2 modeling.
* When COSMIC observations are considered for validation, IRTAM improves neither the IRI _fo_F2 modeling nor the IRI _hm_F2 modeling.  
These results highlight that IRTAM, in contrast to most of assimilation models, has ample room for improvement. The points that in our opinion deserve specific attention are: the bad performance of IRTAM when modeling _fo_F2 at low latitudes; the global _hm_F2 modeling made by IRTAM which is often unreliable, especially in areas far away from the assimilating sites, where the representation made by IRTAM is at times really different from that of the IRI background; the fact that IRTAM performances are too dependent on the assimilated ionosondes location.  
The improvement in the near real-time specification of the ionospheric F2-layer peak characteristics is becoming more and more important nowadays for telecommunication purposes and for Space Weather applications in general. For example, [PERSON] et al. [74] have recently applied IRTAM as the Floating Potential Measurement Unit (FPMU) back-up system that will be used to support the International Space Station (ISS) program. IRTAM _fo_F2 maps were used by [PERSON] et al. [75] to provide global maps of the ionospheric equivalent slab thickness (\(\tau\)) parameter that are delivered through the GAMBIT Explorer software ([[http://giro.uml.edu/GAMBIT](http://giro.uml.edu/GAMBIT)]([http://giro.uml.edu/GAMBIT](http://giro.uml.edu/GAMBIT)), accessed on 30 July 2021). An improved real-time specification of \(\tau\) on a global basis is very important because this parameter describes the shape of the ionospheric electron density profile; thus, an improved specification of \(\tau\) can help empirical models such as IRI in the description of the profile shape, especially the topside part [76; 77; 78; 79].  
Since in the incoming years the applications based on a near real-time specification of the ionospheric conditions will increase in number, an ever more reliable and robust representation of the ionosphere will become of outstanding importance. This is why near real-time data-assimilation models such as IRTAM need continuous improvement and refining, on the one hand to improve the climatological description of the ionosphere made by IRI, and on the other hand to pave the way for a reliable ionospheric weather description.  
Conceptualization, A.P., M.P. ([PERSON]); methodology, A.P.; data curation, A.P.; investigation, all authors; validation, all authors; formal analysis, A.P.; writing--original draft preparation, A.P., M.P. ([PERSON]); writing--review and editing, all authors. All authors have read and agreed to the published version of the manuscript.  
This research is partially supported by the Italian MIUR-PRIN grant 2017 APKP7T on Circum Terrestrial Environment: Impact of Sun-Earth Interaction.