Union Radio Scientifique Internationale Research Articles

A Combination Prediction Model of Long-Term Ionospheric foF2 Based on Entropy Weight Method.

It is critically meaningful to accurately predict the ionospheric F2 layer critical frequency (foF2), which greatly limits the efficiency of communications, radar, and navigation systems. This paper introduced the entropy weight method to develop the combination prediction model (CPM) for long-term foF2 at Darwin (12.4° S, 131.5° E) in Australia. The weight coefficient of each individual model in the CPM is determined by using the entropy weight method after completing the simulation of the individual model in the calibration period. We analyzed two sets of data to validate the method used in this study: One set is from 2000 and 2009, which are included in the calibration period (1998–2016), and the other set is outside the calibration cycle (from 1997 and 2017). To examine the performance, the root mean square error (RMSE) of the observed monthly median foF2 value, the proposed CPM, the Union Radio Scientifique Internationale (URSI), and the International Radio Consultative Committee (CCIR) are compared. The yearly RMSE average values calculated from CPM were less than those calculated from URSI and CCIR in 1997, 2000, 2009, and 2017. In 2000 and 2009, the average percentage improvement between CPM and URSI is 9.01%, and the average percentage improvement between CPM and CCIR is 13.04%. Beyond the calibration period, the average percentage improvement between CPM and URSI is 13.2%, and the average percentage improvement between CPM and CCIR is 12.6%. The prediction results demonstrated that the proposed CPM has higher precision of prediction and stability than that of the URSI and CCIR, both within the calibration period and outside the calibration period.

IEEE Radio 2019

The 2019 edition of the international conference, IEEE Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2019), was hosted in Reunion Island for the second time. This seventh edition of the conference was held from September 23 to 26, 2019, at the Lux Resort & Hotel, Saint-Gilles Les Bain. The conference was managed by the Radio Society (Mauritius) and financially sponsored by the IEEE Antennas and Propagation Society (AP-S). Région Réunion financially supported the conference, and the Union Radio Scientifique Internationale (URSI) provided technical cosponsorship. The Local Organizing Committee consisted of researchers from Centrale Supélec, France, the University of Mauritius, and the University of Reunion Island.

Editor’s Foreword

The 2019 edition of the IEEE Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2019) international conference was hosted in Reunion Island for the second time. This seventh edition of the conference was held from 23rd to 26th September 2019 at the Lux Resort & Hotel, Saint-Gilles Les Bain. The conference was managed by the Radio Society (Mauritius) and financially sponsored by the IEEE Antennas and Propagation Society (AP-S). Région Réunion financially supported the conference and Union Radio Scientifique Internationale (URSI). provided technical co-sponsorship. The Local Organising Committee consisted of researchers from CentraleSupélec, France, University of Mauritius and University of Reunion Island.IEEE RADIO 2019 was attended by participants from about twenty different countries. The conference featured a tutorial on the design of radio amateur networks followed by presentations of radio amateur activities in Mauritius and Reunion Island. Projects related to humanitarian activities were discussed during a special session organized by the IEEE Special Interest Group on Humanitarian Technology (SIGHT) Indian Ocean. Two workshops, open to all the participants of the conference, were organized in conjunction with the conference. The first workshop addressed measurements and simulations for industrial applications and development of standards. The second workshop was dedicated to the CARERC (Cartographie Electromagnétique par Réseaux de Capteurs) project that was undertaken by colleagues at University of Reunion Island during the past years. The regular sessions covered topics such antenna design, bioelectromagnetics, devices and circuits, wireless communication and tracking systems. Three internationally recognized scientists delivered invited talks during the conference.The oral presentations of students and young scientists were evaluated by a jury. A shield and a cash prize of 300 Euros were awarded to the Best Young Scientist less than 36 years old. The presenters of the first, second and third Best Student Papers were awarded shields and cash prizes of 300 Euros, 200 Euros and 100 Euros, respectively. The AP-S sponsored Industrial Engineering Paper Award, consisting of a shield and a cash prize of 300 Euros, was presented to the author of the paper presenting the most innovative and significant contribution in terms of practical industrial engineering related to the fields of antennas, electromagnetics and propagation.All the 2-page short papers that were effectively presented during the conference have already been published on the IEEE Xplore Digital Library. A call for the submission of 4-page extended versions of the conference papers was launched for publication as a volume in the IoP Conference Series: Materials and Engineering (MSE). After the peer-review process by the distinguished members of the Scientific Committee, only four papers were accepted and published in this volume of IoP Conference Series: MSE.EditorVikass Monebhurrun

Diurnal variation of F2-layer critical frequency under solar activity recurrent conditions during solar cycles 21 and 22 at Ouagadougou Station: Prediction with IRI-2012

This paper presents foF2 data recorded at Ouagadougou Ionosonde Station and compares them with IRI-2012 model results through its two subroutines, Union Radio Scientifique Internationale (URSI) and Comite Consultatif International des Radio Communications (CCIR) during recurrent solar activity. Except for the solar cycle maximum period, measured data profiles corroborate with the signatures of E×B drift. IRI- 2012 subroutine URSI is not consistent with observed electrodynamics during any solar cycle phase, while CCIR predictions are consistent with the measured data during the solar maximum and declining phases. Investigation on the relative deviation module mean (RDMM) shows poor agreement between measurements and predictions with IRI most of the time. However, the deviation percentages indicate good correlation between URSI predictions and data from the ionosonde, except for solar ascending phase. Good correlation with CCIR is only obtained during the solar cycle minimum and maximum phases. From a quantitative point of view, this study shows that predictions with URSI are closer to experimental measurements. The investigations show good agreement between model and in situ measurement during the day. Significant differences are recorded at night, especially from midnight to sunrise. There is necessity to improve IRI model for equatorial regions to better predict foF2 variation. Key words: Ionosphere, foF2, Solar cycle, IRI model.

2018 IEEE Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2018)

EDITOR’S FOREWORDThe 2018 edition of the IEEE Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2018) international conference was hosted once again in Mauritius, the country where the first three editions of the conference were organized in 2012, 2014 and 2015. Dr. Arjoon Suddhoo, Executive Director of the Mauritius Research Council (MRC), officially opened this sixth edition of the conference that was held from 15th to 18th October 2018 at the Hilton Resort & Spa, Wolmar, Mauritius. The conference was managed by the Radio Society (Mauritius) and financially sponsored by the IEEE Antennas and Propagation Society (AP-S). IEEE RADIO 2018 was technically co-sponsored by IEEE Region 8 and Union Radio Scientifique Internationale (URSI). Researchers from CentraleSupélec, France, University of Mauritius and Université de La Réunion formed the local organizing committee.Participants from over twenty different countries spanning all five continents attended IEEE RADIO 2018. The conference featured fourteen regular sessions covering diverse topics such as antenna design, devices and circuits, wave propagation and scattering, wireless communication systems, computational electromagnetics, and biological effects of electromagnetic fields. A tutorial on computational electromagnetics was proposed on Monday morning. During the opening ceremony, the IEEE Ulrich L. Rohde Humanitarian Technical Field Project Award was presented to IEEE Special Interest Group on Humanitarian Technology (SIGHT) Indian Ocean for the Agriculture, Climate and Technology in Indian Ocean Network (ACTION) project. Moreover, a SIGHT Event was organized on Monday afternoon during which representatives from different IEEE SIGHT Groups presented their humanitarian activities and projects. Three internationally recognized scientists delivered invited talks during the conference.A jury evaluated the oral presentations of students and young scientists. The Best Young Scientist less than 36 years old received a shield and a cash prize of 300 Euros. The first, second and third Best Student Papers were awarded shields and cash prizes of 300 Euros, 200 Euros and 100 Euros, respectively. The inaugural Industrial Engineering Paper Award, consisting of a shield and a cash prize of 300 Euros, was presented to the author of the paper presenting the most innovative and significant contribution in terms of practical industrial engineering related to the fields of antennas, electromagnetics and propagation.The 2-page short papers presented during the conference have already been published on the IEEE Xplore Digital Library. After the conference, the authors of the accepted and presented papers were invited to submit an extended version (limited to a maximum of 4 pages) for publication as a volume in the IoP Conference Series: Materials and Engineering (MSE). Eighteen papers were submitted. After the peer-review process by the distinguished members of the Scientific Committee, only nine papers were accepted and published in this volume of IoP Conference Series: MSE.EditorVikass Monebhurrun

IEEE Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2017)

EDITOR’S FOREWORDProfessor Weng Cho Chew, IEEE Antennas and Propagation Society (APS) President-Elect 2018, officially opened the fifth edition of the 2017 IEEE Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2017) international conference that was held at the Protea Hotel by Marriott Cape Sea Point, Cape Town, South Africa from 25th to 28th September 2017. The conference was organized by the Radio Society (Mauritius) and financially sponsored by IEEE APS. IEEE RADIO 2017 was also technically co-sponsored by Union Radio Scientifique Internationale (URSI) and IEEE Region 8.The local organizing committee comprised researchers from Centrale Supélec, France, Université de La Réunion, University of Mauritius and Square Kilometre Array (SKA) Africa. We are grateful to SKA Africa, Newton Fund, Development in Africa for Radio Astronomy (DARA), Mobile & Wireless Forum (MWF) and Computer Simulation Technology (CST) for providing financial sponsorship for the conference.

The Empirical Canadian High Arctic Ionospheric Model (E‐CHAIM): NmF2 and hmF2

AbstractWe 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 data set 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 Union Radio Scientifique Internationale maps. At all stations within the polar cap, we see drastic RMS error improvements over the IRI by up to 1.3 MHz 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, 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 ~13 km for E‐CHAIM, with IRI2007 overall hmF2 errors ranging between 16 km and 22 km. 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.

EDITOR’S FOREWORD

Dr. Philippe Jean Pierre, President of the Regional Committee for Innovation of Reunion Island, officially opened the fourth edition of the Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2016) that was held at Hotel Le Récif, Saint-Gilles Les Bains, Reunion Island from 10th to 13th October 2016. The conference was organized by the Radio Society (Mauritius) and it was jointly sponsored by the IEEE Antennas and Propagation Society (APS) and Université de La Réunion. In addition, IEEE RADIO 2016 was technically co-sponsored by Union Radio Scientifique Internationale (URSI), IEEE Region 8 and IEEE France Section. The local organizing committee consisted of researchers from CentraleSupélec, France, Université de La Réunion and University of Mauritius.IEEE RADIO 2016 is the fourth of a series of conferences, covering the fields of antennas and propagation, organized in the Indian Ocean region. The idea behind the organization of the RADIO international conference originated at the start of this decade following discussions with engineers and researchers from countries of the Indian Ocean region as well as from other parts of the world. It was unanimously acknowledged that there was an urgent need to initiate a platform that would provide engineers and researchers of the Indian Ocean region opportunities to share knowledge in the field of radio frequency engineering with their international peers. IEEE RADIO 2016 gathered participants from over twenty countries coming from different regions of the world including Africa, Asia, Australia, Europe, Middle-East and North America, and we can confidently say that we have succeeded in our goal.The conference featured fourteen oral sessions on state-of-the-art research themes including antenna design, bio-electromagnetics, computational electromagnetics, devices and circuits, metamaterials and applications, radio astronomy, remote sensing and wireless sensor networks. Invited talks were delivered by Prof. Tapan Sarkar from Syracuse University, USA, Prof. Qing Liu from Duke University, USA and Prof. Monaï Kraikriksh from King Mongkut’s Institute of Technology, Ladkrabang, Thailand. A special session, organized by Dr. Eric Mokole, Vice-Chair of IEEE APS Special Interest Group on Humanitarian Technology (SIGHT), was dedicated to humanitarian activities and projects in the Indian Ocean.All accepted papers that were effectively presented during the conference were submitted to the IEEE Xplore Digital Library. And, in line with the previous editions, a call to extended contributions for publication as a volume in the IoP Conference Series: Materials Science and Engineering (MSE) was made. All of the twenty full papers that were submitted were then peer-reviewed, revised according to the reviewers’ comments and ultimately fourteen papers were accepted for publication in this volume.This fourth edition of the IoP Conference Series: MSE dedicated to selected papers presented at IEEE RADIO 2016 is representative of the scientific content and quality of the RADIO international series of conferences.EditorVikass Monebhurrun

IEEE Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2015)

EDITOR'S FOREWORDHer Excellency, Dr. Ameenah Gurib-Fakim, President of the Republic of Mauritius, officially opened the third edition of the Radio and Antenna Days of the Indian Ocean (IEEE RADIO 2015) that was held at the Long Beach Resort, Belle Mare, Mauritius from 21st to 24th September 2015. It was an honor and a great pleasure for all those involved in its organization to welcome the participants to IEEE RADIO 2015. The aim of the conference is to discuss recent developments, theories and practical applications covering the whole scope of radio-frequency engineering, including radio waves, antennas, propagation, and electromagnetic compatibility. The Organizing Committee consisted of scientists from CentraleSupélec, France and the University of Mauritius. All of them are also active members of the Radio Society (Mauritius) that organized IEEE RADIO 2015 in collaboration with the IEEE Antennas and Propagation Society. Union Radio Scientifique Internationale (URSI) provided technical co-sponsorship for the conference. We are thankful to CST, a major player in computational electromagnetics, for financially supporting this event for the third time. Following numerous requests, the Island of Mauritius, worldwide known for its white sandy beaches and pleasant tropical atmosphere, was once again chosen for the organization of the 3rd edition of the RADIO international conference. IEEE RADIO 2015 brought together participants from about twenty different countries. It featured sixteen oral sessions on state-of-the-art research themes including antenna design, electromagnetic compatibility, wireless communication, wireless power transfer, numerical modeling and medical and industrial applications of electromagnetic fields. A half-day workshop was organized by CST on the first day of the conference to present the latest version of the CST Studio Suite. Three internationally recognized scientists delivered invited lectures. All accepted papers that were effectively presented during the conference were submitted to the IEEE Xplore Digital Library. In line with the previous editions, a call to extended contributions for publication as a volume in the IOP Conference Series: Materials Science and Engineering (MSE) was made. Following the call, thirty full papers were received. All submitted contributions were then peer-reviewed, revised according to the reviewers' comments, and eventually accepted or rejected. Eighteen papers were ultimately accepted for publication in this volume. It is believed that the IOP Conference Series dedicated to the RADIO international conference provides an excellent source of pertinent and long-lasting scientific material in the numerous fields covered by conference. Editor Vikass Monebhurrun

The variability and IRI2007-predictability of hmF2 over South Africa

This paper presents an investigation into the variability and predictability of the maximum height of the ionospheric F2 layer, hmF2 over the South African region. Data from three South African stations, namely Madimbo (22.4°S, 26.5°E, dip angle: −61.47°), Grahamstown (33.3°S, 26.5°E, dip angle: −64.08°) and Louisvale (28.5°S, 21.2°E, dip angle: −65.44°) were used in this study. The results indicate that hmF2 shows a larger variability around midnight than during the daytime for all seasons. Monthly median hmF2 values were used in all cases and were compared with predictions from the IRI-2007 model, using the URSI (Union Radio-Scientifique Internationale) coefficient option. The analysis covers the diurnal and seasonal hourly hmF2 values for the selected months and time sectors e.g. January, July, April and October for 2003 and 2005. The time ranges between (03h00–23h00UT; LT=UT+2h) representing the local sunrise, midday, sunset and midnight hours. The time covers sunrise, midday, sunrise, and midnight hours (03–06h00UT, 07–11h00UT, sunrise 16–18h00UT and 22–23h00UT; LT=UT+2h). The dependence of the results on solar activity levels was also investigated. The IRI-2007 predictions follow fairly well the diurnal and seasonal variation patterns of the observed hmF2 values at all the stations. However, the IRI-2007 model overestimates and underestimates the hmF2 value during different months for all the solar activity periods.

Comparison between IRI-2001 predictions and observed measurements of hmF2 over three high latitude stations during different solar activity periods

The monthly median values of the height of peak electron density of the F2-layer (hmF2) derived from ionosonde measurements at three high latitude stations, namely Narssarssuaq (NAR) (61.2 °N, 314.6 °E), Sondrestrom (SON) (67°N, 309.1°E) and College (COL) (69.9°N, 212.2°E) were analyzed and compared with the International Reference Ionosphere (IRI-2001) model, using Comité Consultatif International des Radio communications) (CCIR and Union Radio-Scientifique Internationale (URSI) options. The analysis covers hmF2 values for March Equinox (February, March, April), June Solstice (May, June, July), September Equinox (August, September, October), and December Solstice (November, December, January), during periods of high (2000–2001), medium (2004–2005) and low (2007–2008) solar activity. Generally, the IRI-2001 prediction follow fairly well the diurnal and seasonal variation patterns of the observed values of hmF2 at all the stations. However, IRI-2001 overestimates and underestimates hmF2 at different times of the day for all solar activity periods and in all the seasons considered. The percentage deviation never exceeded 20%, except during DEC SOLS at COL and SON and during MARCH EQUI at SON during low solar activity period. For all solar activity periods considered, both the URSI and CCIR options of the IRI-2001 model give hmF2 values close to the ones measured, but the URSI option performed better than the CCIR option.

Comparison between observed ionospheric foF2 and IRI-2001 predictions over periods of severe geomagnetic activities at Grahamstown, South Africa

The observed ionospheric F2 critical frequency ( foF2) values over a South Africa mid-latitude station, Grahamstown, (geographic coordinates: 33.3°S, 26.5°E), were analysed and compared with International Reference Ionosphere (IRI) model, using the CCIR (Comite´ Consultatif International des Radio communications) and URSI (Union Radio-Scientifique Internationale) coefficients, during four geomagnetically disturbed days in the year 2000. These days are April 5, May 23, August 10 and September 15. The data were analysed for five days around the storm day. Comparisons between the IRI-2001 predicted foF2 values, using both CCIR and URSI coefficients and the observed values are shown with their root-mean-square error (RMSE) and the relative deviation module mean (rdmm) for the various storm periods. The CCIR option performed more accurately than the URSI option. In general, the model generates good results when compared with observed foF2 values during geomagnetic storms, although some improvements are still necessary to be implemented in order to obtain better predictions.

Comparisons of observed ionospheric F2 peak parameters with IRI-2001 predictions over South Africa

The monthly means of the ionospheric F2 peak parameters ( foF2 and hmF2) over three stations in South Africa (Grahamstown, 33.3°S, 26.5°E, Madimbo, 22.4°S, 26.5°E, and Louisvale, 28.5°S, 21.2°E) were analyzed and compared with IRI-2001, using CCIR (Comité Consultatif International des Radio communications) and URSI (Union Radio-Scientifique Internationale coefficients) options. The analysis covers a few selected quiet and disturbed days during various seasons represented by the months of January, April, July and October 2003. IRI-2001 generally overestimates hmF2 for both quiet and disturbed days and it overestimates and underestimates foF2 at different times for all the stations. In general, foF2 is predicted more accurately by IRI-2001 than hmF2, and on average, the CCIR option performed better than the URSI option when predicting both foF2 and hmF2. In general, the model generates good results, although some improvements are still necessary to be implemented in order to obtain better predictions. There are no significant differences in the model predictions of hmF2 and foF2 for quiet and disturbed days.

On the global model for foF2 using neural networks

The use of neural networks (NNs) has been employed in this work to develop a global model of the ionospheric F2 region critical frequency, foF2. The main principle behind our approach has been to utilize parameters other than simple geographic coordinates, on which foF2 is known to depend, and to exploit the ability of NNs to establish and model this nonlinear relationship for predictive purposes. The foF2 data used in the training of the NNs were obtained from 59 ionospheric stations across the globe at various times from 1964 to 1986, on the basis of availability. To test the success of this approach, one NN (NN1) was trained without data from 13 stations, selected for their geographic remoteness, which could then be used to validate the predictions of the NN for those remote coordinates. These stations were subsequently included in our final NN (NN2). The input parameters consisted of day number (day of the year), universal time, solar activity, magnetic activity, geographic latitude, angle of meridian relative to subsolar point, magnetic dip angle, magnetic declination, and solar zenith angle. Comparisons between foF2 values determined using NNs and the International Reference Ionosphere (IRI) model (from Union Radio Scientifique Internationale (URSI) and International Radio Consultative Committee (CCIR) coefficients) with observed values are given with their root‐mean‐square (RMS) error differences for test stations. The results from NN2 are used to produce the global behavior of hourly values of foF2 and are compared with the IRI model using URSI and CCIR coefficients. The results obtained (i.e., RMS error differences), which compare favorably with the IRI models, justify this technique for global foF2 modeling.

INTERNATIONAL STANDARD MODEL OF THE EARTH'S INOSPHERE AND PLASMASPHERE

The standard plasmasphere-ionosphere model of the International Standardization Organization is aimed at providing the distributions of the electron density, total electron content, temperature and effective collision frequency of electrons at altitudes of 65-20000 km (or to the plasmapause) over the Earth, geodetic latitudes of 80 N to 80 S, any longitude, day of the year, and indices of solar and geomagnetic activity. It includes the International Reference Ionosphere developed by the Union Radio-Scientifique Internationale and the Committee on Space Research, and the Russian standard model of the ionosphere. Two modes of operation are envisaged: the climatological monthly average prediction and dynamic short-term forecast of space weather parameters. The reliability of results is improved on input of pre-history of observable solar and geophysical parameters. The software of the standard model is available via the Internet.

Theoretical modeling of ƒoF2 and hmF2 ionospheric parameters during a strong magnetic disturbance

The theoretical data assimilative model of the ionosphere (TDAMI) was created to answer the most challenging problem in ionospheric physics: modeling the ionospheric disturbances (in particular, parameters related to the peak of the F layer ƒoF2 and hmF2) during geomagnetic storms. It is an analytical model that calculates maximum electron density (Nm) distribution and the height of this maximum (hm) as a function of time, latitude, longitude, season and solar activity. Tested as a “climatological”, i.e., monthly average, model over the worldwide midlatitude ionospheric data set for different seasons and solar activity conditions, TDAMI yields results comparable with the well‐known empirical models of the International Radio Consultative Committee (CCIR) and the Union Radio Scientifique Internationale (URSI). The mean annual relative error ƒoF2 is <8% for all levels of solar activity, while the mean seasonal errors do not exceed 12%. A comparison between the model simulations and all existing vertical incidence (VI) data for the geomagnetically disturbed period October 10–11, 1988, shows that TDAMI adequately simulates the UT‐latitudinal‐longitudinal dependence of the ionospheric reaction to the geomagnetic disturbance. During the hours of maximum depletion in the electron density, the improvement achieved by the model is more than 70–80% compared to international reference ionosphere (IRI) global distributions (by CCIR and URSI coefficients sets). The maximum TDAMI model error is 20–25%.

The true‐height analysis of ionograms using simplified numerical procedures

In this paper a numerical integration method termed “μ't fitting” for application to the true‐height analysis of digitally recorded ionograms is introduced. This method can be used to analyze either the O or X waves in an ionogram and includes the effect of the Earth's magnetic field. For the second order polynomial profile analysis the μ't fitting technique utilizes 38–62% fewer numerical operations than the Gaussian quadrature integration method. Applying 5‐ (12‐) term μ' t fitting to 100 data points, the method completes a true‐height analysis in 0.77 (1.43) s, using an 80486/33 computer system. Furthermore, applying this technique to the overlapping Chapman model profile adopted by Union Radio Scientifique Internationale (URSI) Working Group G.6.2 (McNamara and Titheridge, 1977) yields rms errors of 8.3 and 7.0 meters for the O and X wave components (12‐term μ't fitting), over a set of 22 selected frequencies.

Parallel electric fields in lab and space plasmas reviewed

A symposium was held at the Union Radio Scientifique Internationale (URSI) General Assembly in Kyoto in 1993 to review research concerning electric fields that have a component parallel to magnetic field lines; that is, when E.B is not equal to zero. Under these conditions the frozen‐in‐theorem of ideal magnetohydrodynamics is not applicable. Indeed, E.B = 0 is one of the cornerstone conditions on which the demonstration of this well‐known theorem is founded.The similarity between laboratory double layers and those observed in the magnetosphere is not always obvious. However, the symposium, Parallel Electric Fields in Laboratory and Space Plasmas, showed that cross fertilization of laboratory plasma physics and space plasma physics can be achieved.

Solar‐terrestrial predictions workshop held in Canada

Scientists from solar, magnetospheric, and ionospheric physics and geomagnetism, as well as forecasters of solar‐terrestrial conditions and users affected by the solar‐terrestrial environment attended the Solar‐Terrestrial Prediction Workshop, held from May 18 to 22, 1992, in Ottawa, Canada. More than 150 scientists from seventeen countries came together to communicate and exchange their knowledge and expertise on the forecasting of solar‐terrestrial conditions.This meeting was the fourth in a series organized by the International Ursigram and World Service (IUWDS), a joint service of the Union Radio Scientifique Internationale (URSI), the International Astronomical Union (IAU), and the International Union of Geodesy and Geophysics (IUGG). The local organizer of the workshop was the Ottawa Regional Warning Center, a component of the Geological Survey of Canada.

Evaluation of six ionospheric models as predictors of total electron content

We have gathered total electron content (TEC) data from a range of mid‐latitudes and low latitudes and longitudes for a wide range of solar activity. This data was used to evaluate the performance of six publicly available ionospheric models as predictors of total electron content. TEC is important for correcting modern DoD space systems, which propagate radio waves from the earth to satellites, for time delay effects of the ionosphere. The TEC data were obtained from polarimeter receivers located in North America, the Pacific, and the East coast of Asia. The ionospheric models evaluated are (1) the International Reference Ionosphere, (2) the Bent model, (3) the Ionospheric Conductivity and Electron Density model, (4) the Penn State model, (5) the Fully Analytic Ionospheric Model, and (6) a hybrid model consisting of the Union Radio Scientifique Internationale 88 (URSI‐88) coefficients coupled with the Damen‐Hartranft profile model. We will present extensive comparisons between monthly median TEC and model TEC obtained by integrating electron density profiles produced by the six models. These comparisons demonstrate that although most of the models do very well at representing ƒ0F2, none of them do very well with TEC, probably because of inaccurate representation of the topside profile. We suggest that one approach to obtaining better representations of TEC is the use of ƒ0F2 from the CCIR or URSI‐88 coefficients coupled with a good climatological slab thickness model.