Reproducing the Ionosphere Climatology with Different 2D Models
Main Article Content
Abstract
The first global maps of the F2 layer critical frequency (foF2) and the maximum usable frequency factor M(3000)F2 had been produced in 1960’s and approved by the International Telecommunication Union, ITU‑R(CCIR). The CCIR maps are used in conjunction with the International Reference Ionosphere, IRI, and the Ionosphere‑Plasmasphere, IRI‑Plas, model to reproduce foF2, hmF2, 3D spatial structure of the ionosphere and the total electron content, TEC. The more recent global GMF2 model of foF2 and hmF2 is for the first time examined in the present study in conjunction with
IRI‑Plas system for the median prediction of foF2m, hmF2m, the electron density height profile Ne(h) and global grids GIM‑TEC of ТЕСm at altitudes from 65 km to 20000 km (GNSS orbit). Our comparison of IRI‑Plas ‘model’ ТЕСm with the ‘truth’ global UQRG monthly median GIM‑TEC for December 2024 showed RMS ≅ 10 TECu. The accuracy of TECm could be improved to RMS ≅ 5 TECu by implementing the GTEC model into IRI‑Plas yielding the corrected values of foF2cor, hmF2cor, Ne(h)cor and TECcor. We calculated the ‘true’ median foF2 and hmF2 for quiet geomagnetic conditions (ap < 15 nT) from 45 ionosondes located around the world. Three options of IRI‑Plas predictions using CCIR, GMF2 and GMF2cor were compared with the ‘true’ median foF2 and hmF2 from 45 ionosondes located globally for the low solar activity, LSA (2019) and high solar activity, HSA (2024). GMF2 and GMF2cor outperform CCIR at all months of LSA, and in most cases at HSA with the lowest deviation from the reference ionosonde data of foF2 equal to 8.5% (GMF2) at LSA and HSA, and that of hmF2 equal to 9.2% (GMF2cor) at LSA and 5.3% (GMF2) at HSA. Data‑model comparisons at middle and low
latitudes, separated by parallels at ±30° of geomagnetic latitude, shows dominant discrepancies al low latitudes. Since majority of the best results are obtained with GMF2 we recommend the GMF2 foF2 and hmF2 to be default options in IRI and IRI‑Plas models instead of the CCIR prediction.
Article Details
Section
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Open-Access License
No Permission Required
Istituto Nazionale di Geofisica e Vulcanologia applies the Creative Commons Attribution License (CCAL) to all works we publish.
Under the CCAL, authors retain ownership of the copyright for their article, but authors allow anyone to download, reuse, reprint, modify, distribute, so long as the original authors and source are cited. No permission is required from the authors or the publishers.