IRI'97 Workshop Report



New Developments in Ionospheric Modelling and Predictions
---------------------------------------------------------
(Dieter Bilitza)

This workshop was held at the Institute of Atmospheric Research in
Kuehlungsborn, Germany from May 27 to 30. The meeting was jointly
organized by the COSPAR/URSI Working Group on the International
Reference Ionopshere (IRI) and by the European Union Cooperation
in Scientific and Technical Research (COST) project 251 "Improved
Quality of Service in Ionospheric Telecommunication System Planning
and Operation". Having this year's IRI Workshop jointly with COST
in Europe provided an opportunity for a large number of European
scientists to present their IRI-related studies and to participate
in the IRI improvement effort. The 86 participants represented 
Greece (2), Czech Republic (5), UK (13), USA (8), Italy (4), France 
(4), Russia (9), Kazakhstan (1), Bulgaria (3), Germany (14), Poland 
(5), India (1), Argentina (1), Spain (4), Austria (2), Canada (1), 
P.R. China (1), Sweden (3), Turkey (1), Japan (2), Finland (2).

There were more than 100 presentation in 10 sessions entitled: Bottomside 
Ionosphere, Ionospheric Models and HF Propagation, E and D Region, 
Topside Ionosphere, Ionospheric Storms and Trough, Longterm Variation 
and Variability, Ion Composition and Plasma Temperatures, Ion Drift 
and Spread-F, Posters, and Final Discussion. The first session was in 
memoriam of Prof. Lucien Bossy the longtime chairman of the IRI (1984-
1992) who passed away on 21 September 1996. Selected papers from the
workshop will be published as an issue of the Advances in Space Research
with K. Rawer and P. Bradley as the editors.
 
From the application standpoint the "HF propagation" session was
the most interesting. A number of European groups reported about their 
usage of ionospheric models for civil and military HF applications
(Bradley, UK; Cannon, DRA, UK; Levy, RAL, UK; Lundborg, FOA, Sweden).
Anderson (AF Phillips Lab, USA) explained the operational ionospheric 
specification and forecast models that are being used by the US Air Force. 
Application of IRI for altimeter data reduction in conjunction with GPS 
total electron content measurements was discussed by Komjathy (Canada).

Very exciting in terms of progress in improving IRI was the "Ionospheric 
Storm" session. Status reports were presented by Rishbeth (UK),
Fuller-Rowell (NOAA, USA), Pulinets (IZMIRAN, Russia), Kutiev (Bulgaria), 
Bradley (UK) and several others describing their efforts to 
establish the typical stormtime variation patterns and algorithms to
represent these ionospheric storm effects. IRI now includes a code developed 
by the IZMIRAN group in Moscow. Comparisons with observations presented 
in the storm and poster sessions showed the shortcomings of this first model
attempt. As a result of the different efforts an improved description
of storm effects is expected to be ready for inclusion in IRI soon.

Of the many outstanding papers and posters several were of particular 
interest for future improvements of IRI: - Tulunay (Turkey) continued her 
study of the dependence of the critical frequency foF2 on the IMF turnings;
- Grebowsky (GSFC, USA) investigated the differences between AE-C, E and
MSX ion density measurements and the IRI and TDIM predictions; - Oyama
(Japan) presented improvements of the IRI plasma temperature model based
on his Hinotori data; - A new topside model based on a large amount of
Alouette/ISIS topside soundings (Bilitza, USA); - An empirical storm-time 
plasma drift model developed by Scherliess and Fejer (USU, USA); - Several 
papers described improvements of the IRI electron density model in the 
bottomside and F1 region based on the work accomplished during the 1995 
and 1996 IRI Task Force Activities at the International Center for 
Theoretical Physics (ICTP) in Trieste, Italy (Radicella, ICTP, Italy; 
Reinisch, UML, USA; Zhang, PR China; Mosert, Argentina).

During the "Final Discussion" session the IRI Working Group initiated
several projects and decide on several important improvements for the 
next version of IRI. In the D-region the Friedrich (Austria) and 
Danilov (Russia) models will be implemented and will be compared with
EISCAT data (Turunen, Finland). In the E-region the Mahajan (India)
model will used for the valley parameters. A new model for the E peak
height (Kishcha, Russia) will be compared with ionosonde data (Bibl,
UML, USA). With relation to the F1 region and bottomside the group 
strongly endorsed the Task Force Activity (TFA) at ICTP and indicated that
new tables for the bottomside parameters (B0, B1) will be included in IRI as
soon as they are finalized. The improved equatorial and solar activity
coverage of the ICTP data base will provide considerably better IRI
predictions at low latitudes. Inclusion of an plasmaspheric extension
of IRI and of an ion drift model will be discussed with the model authors
(plasmasphere: Gallagher, MSFC, USA; ion drift: Fejer, USU, USA).
Several new members were accepted into the IRI team: B. Zolesi (ING 
Rome, Italy), K. Igarashi (CRL, Japan), I. Kutiev (GI, Bulgaria),
and S. Watanabe (Tohoku U., Japan). 

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