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32nd International Union of Radio Science General Assembly & Scientific Symposium * Montreal, Canada * 19-27 August 2017 Home Page

Scientific Program - Commission G

Commission G Chair:
Prof. Iwona Stanislawska;

Commission G - Tutorial

Tim Fuller-Rowell - "Will We Ever be Able to Model and Forecast the Ionosphere Well Enough to Support the Needs of the Radio Wave Users?"

Convener: Iwona Stanislawska

Commission G - "Data Assimilation Modeling"

Conveners: Ivan Galkin, Bruno Nava, Robert Schunk

Space weather disturbances can adversely affect numerous systems and operations, and many of the applications pertain to the ionosphere and upper atmosphere. Space weather can affect over-the-horizon (OTH) radars, HF communications, surveying and navigation systems including Satellite Based Augmentation Systems (SBAS), surveillance, spacecraft charging, power grids, pipelines. As with meteorology and oceanology, data assimilation has become an important tool for specifying and forecasting space weather disturbances, particularly with regard to the Ionosphere-Thermosphere-Electrodynamics (I-T-E) system. The increased use of data assimilation techniques is a result of both the availability of numerous empirical and physics-based models that can be used to describe the background state and the significant increase in the data available for assimilation. Currently, there are several thousand ground-based GNSS receivers that provide slant TECs, numerous satellites that provide radio occultation measurements, hundreds of ionosondes/digisondes that yield bottom-side electron density profiles, and satellites that provide both ultraviolet (UV) emission data and in situ electron density measurements. The session will focus on research related to data assimilation techniques, background models, data sources, and validation.

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Commission G - "International Reference Ionosphere – Improvement, Validation and Usage"

Conveners: Dieter Bilitza, David Themens

The URSI/COSPAR International Reference Ionosphere (IRI) is an empirical model built on a large volume of space- and ground-based data, with modelling and improvement inputs from a working group of now over 60 international experts, including members of the ground and space observations communities. This session invites talks and posters that report on improvements, validation, and usage of the IRI model. Contributions are encouraged that present new modelling approaches for the parameters currently represented by the IRI and suggestions for additional parameters that should be provided by the model. Of particular interest are applications of the IRI model in scientific studies or operational environments. The IRI model represents spatial and temporal variations of electron density, ion composition, electron temperature, and ion temperature in the altitude range of 50km to 2000km. Additional parameters include total electron content, the probability of the occurrence of spread-F and of an F1 layer, and a representation for the auroral boundaries. Contributions regarding the modelling of any of these parameters are welcome. Of special interest are studies that present extensions of the IRI model parameters to plasmaspheric heights.

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Commission G - "Science with Modern Ionosondes and Associated Instrumentation and Models"

Conveners: Ivan Galkin, Anna Belehaki, John Bosco Habarulema

Eighty five years after the inaugural F-region sounding at Slough observatory, ionosondes are back in the focus of attention. Modern HF ionosphere sounder has evolved into one of the very few providers of the reliable real-time sensor data for several important research and application domains. Space weather nowcast, sensing dynamics of the plasma irregularities, geolocation of HF emitters, ranging over the radio horizon are only a few scenarios in which the ionosondes are uniquely instrumental to the task. The session will review the state-of-art ionosonde-related science and engineering advances, including digital HF technologies, intelligent systems for data interpretation, detection and evaluation of the traveling ionospheric disturbances, information science for timely network data acquisition and dissemination, assimilative modelling of 3D plasma distribution in the ionosphere, sensing the vertical and horizontal plasma transport, concepts and designs for topside ionospheric sounding, and other relevant topics. We welcome contributions on cooperative ionosonde observations with other instrumentation for monitoring the ionospheric plasma.

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Commission G - "Advances in Irregularities and Scintillation Studies"

Conveners: Emanoel Costa, Archana Bhattacharyya

This session emphasizes the latest developments in the study of ionospheric irregularities and scintillation. Papers that focus on the problems of scintillation on satellite-based communication and navigation systems at low and high latitudes, together with the description of models aimed at combating its effects, are particularly welcome. This session's scope also includes new developments in the theory of scintillation. in statistical studies of scintillations, and multi-technique observations of irregularities including in situ observations, relevant to possible prediction of scintillations.

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Commission G - "Incoherent Scatter Radar"

Conveners: Ingrid Mann, Emma Spanswick, Mike Kosch

This session will focus on advances in the field of incoherent scatter radar (ISR) measurement of the geospace environment, the study of the ionosphere and its coupling to the lower atmosphere and magnetosphere. It provides a platform to present results from previous multi-radar experiments and to discuss future plans for coordinated observations with existing and future facilities. This includes long-period co-ordinations similar to the International Polar Year, and the future of the World Day programme, as well as the discussions how to further harmonize the data formats. Contributions are also welcome on planning observations with and making best use of future advanced ISR facilities.

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Commission G - "Design and Application of HF and OTH Radar Systems"

Conveners: Manuel Cervera, Mike Ruohoniemi, Todd Parris

This session is focused on sky-wave High Frequency radar, including operational over-the-horizon radars and the SuperDARN ionospheric research radars and their support instruments. Research topics include: - Antenna design,

  • HF waveforms (radar and sounders),
  • HF digital receivers and signal processing techniques
  • HF radio wave propagation in the ionosphere
  • Space weather monitoring with HF radar observations
  • HF sounding of the ionosphere at all latitudes
  • Ionospheric disturbances and their impacts on HF and OTH systems
  • Application of satellites to HF propagation studies
  • Coordinate registration and multi-mode management
  • Ionospheric Absorption (measurements and modeling)
  • Directional HF noise and interference (measurements and modeling)
  • HF mapping of the terrestrial surface

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Commission G - "Ionospheric Space Weather"

Conveners: Sandro Radicella, Anthea Coster

This session will focus on the ionospheric and space weather events that may impact telecommunications and navigation systems. It will also cover all areas of ionospheric space weather research including modeling and novel observations, using in particular radio waves techniques. Of special interest are papers describing assessment and validation of space weather models, and the justification of the need for new ground and space-borne measurements. Studies and investigations addressed to modeling, forecasting and/or mitigations of ionospheric phenomena due to space weather events, such as ionospheric medium- and small-scale irregularities as revealed by different radio and optical techniques, are also welcome.

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Commission G - "GNSS Applications in Radio Science"

Conveners: Matthew Angling, Seebany Datta-Barua

Global Navigation Satellite Systems (GNSS) such as the Global Positioning System (GPS), Galileo, and Beidou rely on L band trans-ionospheric radio signals for positioning, navigation, and timing (PNT). Such signals are susceptible to ionospheric propagation effects (i.e. phase advance, group delay) that can alter the received signal properties at the receiver. Thus, the ionosphere can affect PNT services. Conversely, the variations in signal properties can be used to probe the ionosphere. This session welcomes papers on: ionospheric science in order to improve future GNSS services; on ionospheric effects on current GNSS services; and on the use of GNSS signals of opportunity for ionospheric remote sensing. Of particular interest are papers on the new GNSS signals that are now available (i.e. Galileo E5a/E5b and GPS L5).

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Commission G - "Improvement of GNSS Radio Occultation Techniques"

Conveners: Norbert Jakowski, Keith Groves

In the last two decades it has been shown that GNSS radio occultation measurements on board Low Earth Orbiting (LEO) satellites provide a powerful tool for monitoring key parameters characterizing the vertical structure of the ionosphere and neutral gas such as the electron density, temperature and/or water vapor, respectively. The effective sounding of the ionosphere and neutral atmosphere was convincingly demonstrated the first time by the GPS-Met experiment onboard Microlab-1, and afterwards by subsequent LEO missions such as CHAMP, GRACE, SAC-C, Formosat/COSMIC and C/NOFS. In the meantime, challenges have arisen concerning the accuracy and reliability of the radio occultation technique for deriving ionospheric and neutral gas parameters. Upcoming missions like COSMIC II and others represent enhanced opportunities to further exploit RO capabilities for monitoring and forecasting ionospheric and tropospheric weather. Thus, to fully utilize these new capabilities the retrieval techniques should be improved in a corresponding manner. Accordingly, we encourage presentations addressing irregularities and gradients of the refractive index, higher order effects of refraction and ray path bending, and assimilation techniques utilizing the basic RO observables. Furthermore, improvements to the specification of upper boundary conditions for ionospheric inversions and the extension of the altitude for neutral gas retrievals are also of interest. Generally speaking, we encourage presentations describing innovative methodologies that address current challenges in RO techniques and synergies of ionospheric and neutral atmosphere retrievals.

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Commission G - "Radio Studies of Mid and Low Latitude Aeronomy"

Conveners: Cesar Valladares, Babatunde Rabiu

The low-latitude ionosphere has long been considered a region that is continuously forced by thermosphere tides and waves that are able to vary the regional and global distribution of the plasma density and seed plasma instabilities. Recently, the mid-latitude ionosphere has also been identified as a region that has an unsettled character due to the development of plasma instabilities (MSTIDs) and the high control that prompt penetration electric fields and the disturbed dynamo exert on the neutral wind and current system. We solicit presentations dealing with recent advances on the stability, dynamics and the MIT coupling of the low and/or mid latitude ionospheres using active or passive radio diagnostics during quiet and disturbed magnetic conditions. We also seek presentations that emphasize the importance of multiple-sensor measurements, regional coverage, and continuous (24/7) operations. Presentations addressing conjugate observations using networks of instruments, coordinated distributed observatories, or others that combine ground- and satellite-instrumentation are also welcome in this session. This session will also discuss future plans in observing mid- and low-latitude aeronomy with various radio instrumentation and planned coordinated radio observations.

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Commission G - "International Beacon Satellite Studies"

Conveners: Patricia Doherty, Andrzej Krankowski, Bruno Nava

This session welcomes papers relevant to the interests of the Beacon Satellite Studies Group of Commission G. The session will begin with a historical view of this studies group and its goals for the future. It will also recap the success of the most recent Beacon Satellite Symposium that was held in 2016. Additional papers are invited that will include all aspects of satellite signals observed on the ground and by receivers on-board satellites. This may include distributed arrays of multi-instruments used for ionospheric monitoring and scientific investigations that span all regions of the globe together will more focused regional investigations. Papers from the developing world are also encouraged.

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Commission G - "Open Session and Recent Results"

Conveners: Iwona Stanislawska, John Mathews, Patricia Doherty

This session welcomes all papers related to the Commission G terms of reference, particularly those not covered by the other G and G/H sessions. The session also welcomes the latest and perhaps more controversial results. Topics may include papers on the radio science of scattering, on the global morphology, theory, modeling and modification of the ionosphere, on the development of tools and networks to measure ionospheric parameters and trends, on the theory and practice of ionospheric radio propagation, and on the application of ionospheric knowledge to radio systems.

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Commissions GEH - "Seismo Electromagnetics (Lithosphere-Atmosphere- Ionosphere Coupling)"

Conveners: Sergey Pulinets, Yasuhide Hobara, Hanna Rothkaehl

The results of electromagnetic and ionospheric monitoring do not leave the place to doubts on the electromagnetic and ionospheric anomalies existence and their connection with seismic activity. Quasistationary electric fields, electromagnetic emissions in wide band of electromagnetic spectrum, anomalies of radio wave propagation, ionospheric anomalies are now the hot spots at all conferences of geophysical thematic. But still we lack the physical substantiation of many of registered effects. Multi‐parameter measurements in seismically active regions and cross validation of results obtained by different groups will help to understand the background physics of the observed anomalies. This session will accept papers demonstrating progress in understanding the ionospheric and electromagnetic effects preceding strong earthquakes including experimental findings and theoretical papers on lithosphere-atmosphere-ionosphere coupling.

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Commissions GF - "Radio Studies on Polar Aeronomy"

Conveners: Giorgiana De Franceschi, V. Chandrasekar, Luca Baldini

At high and low latitudes, the ionosphere can be particularly perturbed and this can be exacerbated around solar activity maxima (but not only). Ionosphere can in turn significantly affect L band (and lower frequency) remote sensing radar systems for Earth science dedicated to observations of surface deformation, cryosphere dynamics, etc. To pose a solid bridge between the ionosphere and remote sensing communities, this session solicits contributions to facilitate exchange of information on their respective states of the art as well as on their future needs. Contributions are welcome on ionosphere and lower troposphere research at high latitudes from GNSS and satellites in situ data dealing with ionospheric irregularities, scintillation, total electron content (TEC) gradients, as well as water vapor measurements. Papers dealing with the assessment and mitigation of "atmosphere" impacts on different applications such as positioning, space weather and remote sensing are highly encouraged. Papers focusing on data processing to support models development are also welcome, as are those based on a multi- instrument approach. Finally, contributions highlighting differences and similarities at high and low latitudes are also appreciated.

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Commissions GH - "Meteors, Collisional EMPs, and Other Highly-Transient Space Plasma Events"

Conveners: John Mathews, Asta Pellinen-Wannberg

This session includes meteoroid impact EMP generation on satellite and planetary surfaces as well as the role of micrometeoroid processes (e.g., sputtering, fragmentation, ablation) and the mass flux on the upper atmosphere and ionosphere, as well as other related highly-transient phenomena. The radio and radar signatures of these processes are also considered.

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Commissions GH - "Plasma Instabilities in the Ionosphere"

Conveners: Frank Lind, Rob Pfaff

Plasma instabilities in the high, middle, and low latitude ionosphere play a key role in the development and evolution of structures in the Geospace environment, including processes in both the E and F regions. They often are associated with irregularities which can be experimentally observed using radar and radio techniques, as well as in-situ observations. Linear and non-linear theory is often used to predict instability thresholds, amplitudes, and velocities. Simulations have recently been quite successful in the detailed study of irregularity micro-structure, time evolution, and k-space behavior. This session will encourage discussion of new developments in the theoretical, simulation, and experimental observations relevant to the study and understanding of ionospheric plasma instabilities. The effects of ionospheric instabilities on other Geospace phenomena will also be of interest. This includes coupling to the magnetosphere and impacts of the lower atmosphere.

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Commissions GHJ - "Workshop on Extreme Space Weather Environments"

Workshop Chair: Mike Hapgood,
Workshop Co-Chair: Terry Onsager,
Conveners: Tony Mannucci, Viviane Pierrard, Mauro Messerotti, Ludwig Klein

Over recent years extreme space weather has been recognized as a global risk with significant societal and economic risks affecting many domains, including but not limited to electrical power grids, satellites, aircraft passengers and crew, avionics, GPS, Galileo and other GNSS positioning, navigation and timing systems and communications systems. In order to evaluate the consequences of space weather on these systems it is essential (a) to identify what are the factors in space weather environments that interact with the systems at risk, and then (b) to estimate what are reasonable worst cases for these factors. This workshop will bring together experts and other interested parties to review and refine a process for developing an internationally agreed set of specifications for the extreme space weather environment, and to test the process by applying it to a number of key domains. It is hoped that this will be the first of a series of workshops, hosted by different organizations and fora, developing these specifications.

The workshop will be led by Professor Mike Hapgood of the Rutherford Appleton Laboratory and will be hosted by URSI Commissions G, H and J. The focus will be on environments appropriate to the work of these Commissions, namely neutron, proton and electron fluxes, solar radio fluxes, ionospheric electron density enhancements, TEC and related electron gradients and radio scintillation. Talks and related presentations will be by invitation only, however, there will be plenty of opportunities for discussion and possibly for showing targeted data and information. Poster papers will be accepted.

The workshop will require additional registration on the URSI web site (but there is no additional cost). Additional preparatory materials will be sent out prior to the meeting.

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Commissions EFGH - "Natural Electromagnetic Noise and Radio Sensing Applications in Terrestrial and Planetary Environments"

Conveners: Y. Hobara, C. Price, T. Ushio, M. Fullerkrug

This joint session aims at presenting recent works on electromagnetic noise and phenomena in the terrestrial atmosphere and upper atmosphere (ionosphere/magnetosphere). Different kinds of electromagnetic noises will be dealt with, including atmospheric noises originated in lightning discharges (ELF Schumann resonances, mesospheric optical emissions etc.), man-made noise and noise due to wave-particle and wave-wave interactions. Corresponding electromagnetic noise environments on other planets are welcome. We are particularly interested in applications of natural EM observations in remote sensing such as monitoring, detecting and forecasting natural hazards, such as thunderstorms, severe weather, space weather and seismic events.

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Commissions EFGHJ - "One-Day Workshop on RFI Mitigation and Characterization"

Conveners: F. Gronwald, R. Bradley, T. Bullet, H. Rothkaehl, D. Le Vine, A. Maitra, M. Haredim, J. Gavan, V. Deniau, P. de Matthaeis

It is the aim of this workshop to bring together researchers, engineers and users from all radio science disciplines to consider how RFI affects their respective fields, to develop mitigation strategies, and to foster cooperation and collaboration. Particular attention will be given to the impact of new and future sources of RFI, spectrum management challenges, and new technology developments. Recent progress towards the ultimate goal of being able to do observations with real-time mitigation of the undesired signals, while leaving the desired signals minimally affected, will be discussed.

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Commissions HG - "Active Experiments"

Conveners: V. Sonwalkar, R. Moore, N. Jackson-Booth, T. Pedersen

This session will cover recent advances in active space experiments, including ionospheric perturbations, disturbances or other effects on the space environment actively produced by high-power RF waves, chemical releases, rocket exhaust, ion engine propulsion systems or other means. In addition to presentations of observations and measurements from recent or novel experiments, theoretical and modeling developments that advance theory beyond the prevailing qualitative and descriptive state toward quantitative and predictive capabilities will also be welcomed. Topics of interest include wave generation stimulated by or propagation modified by artificial effects. Presentations on technologies, such as RF sources or chemical reactions, which may enable new or improved applications in active space experimentation, are also sought. This session will also cover the latest technical and scientific results on and concepts of space-borne radio sounding in terrestrial and extra-terrestrial ionospheres and magnetospheres including previous, current, and planned spaceborne sounders. The basic physics of plasma-wave propagation and of active or passive antennas, in magnetoplasmas in laboratory or space, are important related topics. Investigations of geospace plasma density structures using injected whistler-mode and Z-mode waves are also solicited, as are reviews of earlier radio-sounding accomplishments highlighting outstanding questions yet to be addressed by radio sounders. There is a close connection between active experiments and space-borne sounding: near-field interactions with antennas in a plasma are very similar to high-power radio wave heating and stimulate a variety of resonances which need to be understood to optimize system function and which can also be used for diagnostic purposes. Contributions on such overlapping research areas are especially welcome.

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Commissions HGE - "Atmospheric, Ionospheric, Magnetospheric and High Energy Effects of Lightning Discharges"

Conveners: S. Celestin, N. Liu, M. Fullekrug

The recent discovery that lightning discharges can cause energetic radiation, relativistic particles, and transient luminous events has marked a profound advance in our understanding of the Earth's atmospheric electrodynamic behaviour. This session explores these novel processes and their impact on the atmosphere and the near-Earth environment. The session solicits contributions which advance knowledge in the areas of the global atmospheric electric circuit, lightning physics, transient luminous events, energetic radiation, relativistic particles, and their impact on the Earth's atmosphere, ionosphere and magnetosphere. One key focus of the session will be novel observations on board space platforms, such as the lightning imagers on geostationary satellites, the TARANIS satellite, the ASIM payload on the International Space Station, and related ground based observations and their modelling. Interdisciplinary studies which emphasize the connection between atmospheric layers and the relation between atmospheric electricity and climate change are particularly welcome.

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Commissions JEFGH - "Characterization and Mitigation of Radio Frequency Interference"

Conveners: Frank Gronwald, V. Deniau, Richard Bradley, Terry Bullet, Hanna Rothkaehl, David LeVine, Amit Kumar Mishra, M. Haredim, J. Gavan

In this session, radio frequency interference (RFI) issues will be discussed that are of particular importance for observational sciences such as radio astronomy, microwave remote sensing of the Earth, and solar and ionospheric studies where highly sensitive measurements are necessary.

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Commissions JG - "Ionospheric Models and their Validation"

Conveners: Stefan Wijnholds, Sean Elvidge

The ionosphere has a profound effect on the propagation of radio waves, making measurements of distortions of RF signals an effective tool for ionospheric research. These same distortions hamper ground-based radio astronomical observations of cosmic source structure and position, in particular at frequencies below 1 GHz. Radio astronomers are, therefore, using different ionospheric models to reduce the number of parameters required for calibration of instrumental and environmental effects affecting their observations. In turn this calibration process provides information on the ionospheric conditions above the array, such as turbulence scales, TID wavelengths and TID velocity. This session aims to bring low-frequency radio astronomers and ionospheric researchers together to stimulate cross-fertilization between these two fields with emphases on the modelling of RF propagation through the ionosphere, the ionospheric models themselves and validation of those models.