The paper presents the latest version of the International Reference Ionosphere model (IRI-2016) describing the most important changes and improvements that were included with this version and discussing their impact on the IRI predictions of ionospheric parameters. IRI-2016 includes two new model options for the F2 peak height hmF2 and a better representation of topside ion densities at very low and high solar activities. In addition, a number of smaller changes were made concerning the use of solar indices and the speedup of the computer program. We also review the latest developments toward a Real-Time IRI. The goal is to progress from predicting climatology to describing the real-time weather conditions in the ionosphere.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2016SW001593

International Reference Ionosphere 2016: From ionospheric climate to real‐time weather predictions

. This paper gives a brief overview over the International
Reference Ionosphere (IRI) project and model. IRI is recognized as the
official standard for the ionosphere by the International Standardization
Organization (ISO), the International Union of Radio Science (URSI), the
Committee on Space Research (COSPAR), and the European Cooperation for Space
Standardization (ECCS). Of great importance are the external drivers of the
model that help IRI to represent ionospheric conditions as realistically as
possible. The paper discusses the drivers currently used presents recent
improvements and changes. Besides the standard solar, magnetic, and
ionospheric indices the paper also reports on the adjustment of the model
with data and equivalent indices and on the progress towards a Real-Time IRI
using data assimilation. IRI has been widely validated with many different
data sources and has fared very well in community wide assessment studies.
We present some of these studies and document the wide usages of the model
in the scientific literature. Finally, we present an outlook on things to
come in IRI-2018 and thereafter.

/pdf/iri-the-international-standard-for-the-ionosphere-1icjo40i5q.pdf

IRI the International Standard for the Ionosphere

We present here the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) quiet NmF2, perturbation NmF2, and quiet hmF2 models. These models provide peak ionospheric characteristics for a domain above 50°N geomagnetic latitude. Model fitting is undertaken using all available ionosonde and radio occultation electron density data, constituting a dataset of over 28 million observations. A comprehensive validation of the model is undertaken and performance is compared to that of the International Reference Ionosphere (IRI).

In the case of the quiet NmF2 model, the E-CHAIM model provides a systematic improvement over the IRI URSI maps. At all stations within the polar cap, we see drastic RMS error improvements over the IRI by up to 1.3MHz in critical frequency (up to 60% in NmF2). These improvements occur primarily during equinox periods and at low solar activities, decreasing somewhat as one tends to lower latitudes. Qualitatively, the E-CHAIM is capable of representing auroral enhancements in NmF2, as well as the location and extent of the Main Ionospheric Trough (MIT), not reproduced by the IRI.

The included NmF2 storm model demonstrates improvements over the IRI by up to 35% and over the quiet-time E-CHAIM model by up to 30%.

In terms of hmF2, over the validation periods used in this study, we found overall RMS errors of ~13km for E-CHAIM, with IRI2007 overall hmF2 errors ranging between 16km and 22km. The E-CHAIM performs comparably to or slightly better than the IRI within the polar cap; however, significant improvements are found within the auroral oval.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017JA024398

V.N. Shubin

Papers

Global median model of the F2-layer peak height based on ionospheric radio-occultation and ground-based Digisonde observations