European Union COST Action Models

The European Union has organized a number of activities under a program termed COST, which stands for Cooperation in Scientific and Technical Research, and specific Actions under COST have been sanctioned. The Actions are necessarily Eurocentric, although there are clearly certain developments that apply globally. Three of these COST Actions of relevance to ionospheric modeling, forecasting and telecommunication system effects have been designated as Actions 238, 251 and 271. An Action on Space Weather has also been initiated (i.e., Action 724). In this section we shall identify some aspects of the ionospheric models and related products to the extent they have been developed and are applicable. It is the opinion of this author that the various COST actions are a significant advance in the development of ionospheric modeling, especially models of the empirical variety. It is also clear that the COST programs have succeeded in organizing a viable and productive European space weather program.

We shall make a few remarks about specific COST Actions 238 and 251 products below (i.e., Sections 3.12.3.1 and 3.12.3.2). Additional programmatic information about all Actions, including 271 and 724, are provided in Chapter 6 (i.e., Section 6.6.1).

3.12.3.1 COST Action 238

Details of COST Action 238 may be found in a published final report [Bradley, 1999]. Action 238 is otherwise known as PRIME, standing for Prediction and Retrospective Modeling over Europe. The Action was inaugurated in 1991 and completed in 1995. The objective was to develop improved models of the European ionosphere for telecommunication purposes. There were a number of achievements that are relevant not only for the European region, but they can also be useful for consideration elsewhere. A tangible product from the Action was the development of a computer program based upon adopted procedures that provides for electron density profiles of the ionosphere, total electron content, and other ionospheric characteristics under specified conditions. There are 16 separate output options and a range of presentation methods accommodated. The output options and sub-models are discussed in the final report.

3.12.3.2 COST Action 251

This Action is entitled: Improved Quality of Service in Ionospheric Telecommunication Systems over Europe. Details of COST Action 251 may be found in a published final report [Hanbaba, 1999]. Like Action 238, Action 251 resulted in a computer program that provides ionospheric information. Specifically it enables the calculation of monthly median and instantaneous values of the parameters foF2, M(3000)F2, N(h), and the TEC. If necessary, the parameter can be translated to the height of the maximum of F2 layer ionization using a well-known empirical expression. While the emphasis is on the European theater, there are procedures for interfacing seamlessly with global maps. In Table 3.4 we have a listing of key algorithms used in the Action 251 computer program.

The most interesting of the algorithms in the Action 251 computer program from the perspective of near-real-time prediction services (i.e., nowcasting and short-term forecasting) are PLES2, PLES5, COSTPROF, COSTTEC, and CORLPRED. The models MQMF2R, UNDIV, PLES2, and PLES5 use the ITU-R ionospheric model outside of the so-called COST 251 area of interest; COSTPROF uses the IRI model outside of the COST 251 area. CORLPRED predicts foF2 up to 24 hours in advance at a specified station using an autocorrelation method [Muhtarov and Kutiev, 1998]. At least 20 days of historical data is needed for the CORLPRED program to work properly. There are additional models developed under the Action, not incorporated in the published program.

The CORLPRED software is made available through the Space Research Center in Warsaw, Poland. The basic input data are 23 vertical-incidence sounder stations between 10 degrees West and 90 degrees East Longitude. The latitude range is between ~ 30 degrees North and ~ 70 degrees North. Raw data are converted to maps over this Eurasian region. The forecasting procedure allows prediction of both foF2 and MUF(3000)F2 up to 4 days in advance when 60 days of prior data are used as an input for derivation of an auto-regressive filter. The prior data are, of course, foF2 and M(3000)F2, where it is assumed that MUF(3000)F2 = M(3000)F2'foF2. To produce maps of foF2, for example, a commercial package is applied. This package is not unlike the SURFER program offered by Golden Software in Boulder, Colorado. It has an option for mapping called Kriging, a method that operates efficiently for sparse data sets. Sample maps offoF2 for the forecast and measurement mode are shown in Figure 3-37. While this corresponds to a quiet ionosphere, it seems apparent that the results are quite acceptable.

Table 3.4: List of Models contained in Action 251 Computer Program

Program Name

Ionospheric Parameter

Presentation of Output

MQMF2R

foF2

long-term map

UNDIV

M(3000)F2

long-term map

PLES2

foF2

instantaneous map

PLES5

M(3000)F2

instantaneous map

COSTPROF

N(h)

long-term and instantaneous map

COSTTEC

TEC

long-term map

CORLPRED

foF2

short-term forecasting

Other forecasting methods developed under COST 251 included separate neural network approaches advanced by the UK DERA organization and by Tulunay et al. [1999]. The DERA method reportedly can predict from 1 hour to 24 hours in advance. The Tulunay approach was designed to predict foF2 one hour in advance. Multi-regression approaches for short-term prediction offoF2 have also been developed under the Action.

Of special interest are forecast models for the TEC. As indicated above, CORLPRED is the Action-approved method for instantaneous values of foF2 and M(3000)F2. Using forecast values of foF2 and M(3000)F2 data, and using an appropriate profile model, CORLPRED can be extended to do TEC forecasting and mapping. COSTPROF is the sounder-based model used to forecast the TEC, based upon work by Cander et al. [1999], Figure 3-38 illustrates some of the difficulties in the approach.

Under the Action 251, GPS-TEC data sources were also investigated, but most of the original emphasis was on extrapolation of sounder results using COSTPROF. This emphasis has changed in the time since COST Action 251 was finalized. Other "novel" data sources for investigating the effects on earth-space systems include ionospheric tomography and GPS occultation measurements.

Figure 3-37: Pair of maps showing the actual measured foF2 for the COST 251 area (top) and the predicted map (bottom). The prediction was 24 hours in advance. The conditions were not disturbed. The period of the forecast was 1200 UT on 12 May 1998. Original illustrations by courtesy of Space Research Center, Warsaw, Poland.

Figure 3-37: Pair of maps showing the actual measured foF2 for the COST 251 area (top) and the predicted map (bottom). The prediction was 24 hours in advance. The conditions were not disturbed. The period of the forecast was 1200 UT on 12 May 1998. Original illustrations by courtesy of Space Research Center, Warsaw, Poland.

3.12.3.3 The ESA Space Weather Working Team

While not part of the COST program (viz., Action 724), the SWWT was set up to advise the European Space Weather Advisory Committee, and it provides advice to ESA on various space weather strategies. See Section 6.6.1 for additional programmatic information.

Figure 3-38: Pair of maps showing the actual TEC for the COST 251 area (top) and the predicted map (bottom). The period of the measurement and forecast was 20 January 1999.The prediction was 24 hours in advance. The COSTPROF model was used. The conditions were not disturbed. Illustrations provided by courtesy of the Space Research Center, Warsaw, Poland.

20 30 40 50 60 Geographic Longitude (cleg E)

Figure 3-38: Pair of maps showing the actual TEC for the COST 251 area (top) and the predicted map (bottom). The period of the measurement and forecast was 20 January 1999.The prediction was 24 hours in advance. The COSTPROF model was used. The conditions were not disturbed. Illustrations provided by courtesy of the Space Research Center, Warsaw, Poland.

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