SWR4 – Interactions in the Earth’s Magnetosphere-Ionosphere-Thermosphere System and their Space Weather Impact
Talks
SWR4.1 Mon 4/11 14:00-16:00, room C2A – Mondego
Author(s): Maxime Grandin, Bea Gallardo-Lacourt, Mathieu Barthelemy, Emma Bruus, Rowan Dayton-Oxland, Eric Donovan, Katie Herlingshaw, Eero Karvinen, David Knudsen, Donna Lach, Vincent Ledvina, Carlos Martinis, Lena Mielke, Toshi Nishimura, Noora Partamies, Chris Ratzlaff, Marjan Spijkers, Neethal Thomas, the ARCTICS collaborators
University of Helsinki, Finland; NASA/GSFC and Catholic University of America, USA; Université Grenoble Alpes, France; Sodankylä Geophysical Observatory, Finland; University of Southampton, UK; University of Calgary, Canada; University Centre in Svalbard, Norway; Citizen Scientist, Finland; University of Calgary, Canada; Citizen Scientist, Canada; University of Alaska Fairbanks, USA; Boston University, USA; University Centre in Svalbard, Norway; Boston University, USA; University Centre in Svalbard, Norway; Citizen Scientist, Canada; Citizen Scientist, Netherlands; Sodankylä Geophysical Observatory, Finland
Abstract: With the tremendous technological improvement of commercial cameras and smartphones, a growing number of (professional and amateur) auroral photographers capture high-quality images of the nightsky. This novel type of optical data has enabled the discoveries of previously unknown optical emission displays which reveal the presence of complex and unexplored processes at work in the near-Earth plasma. Those discoveries are the result of what is known as “citizen science”, i.e. scientific research involving contributors outside the academic world and who provide data and are co-authors of the resulting publications. Typically, auroral citizen science has been combining astrophotographers’ pictures with observations from ground-based instruments and satellites, hence requiring a multidisciplinary approach and a broad range of expertise and skills.
The ARCTICS (Auroral Research Coordination: Towards Internationalised Citizen Science) Working Group sponsored by the International Space Science Institute in Bern brings together academics and citizen scientists from Europe, North America and Oceania to investigate auroral and subauroral physics. We combine citizen scientist observations with satellite and ground-based measurements to shed light on elusive optical phenomena such as STEVE, the dunes, fragments, and continuum emission. We also set up a Handbook to provide guidance and recommendations for collaborations between academics and citizen scientists to be as smooth and fruitful as possible.
In this presentation, we will give an overview of the ARCTICS collaboration and highlight some of its first results.
Author(s): Audrey Schillings, Gemma Bower, Steve Milan, Anna Willer, Nils Olsen, Marie Eldor, Hermann Opgenoorth, Maria Hamrin
University of Leicester, UK, Umeå University, Sweden DTU Space, Denmark; University of Leicester, UK; University of Leicester, UK; DTU Space, Denmark; DTU Space, Denmark; DTU Space, Denmark; Umeå University, Sweden; Umeå University, Sweden
Abstract: Geomagnetic storms and substorms induce significant disturbances in the Earth’s magnetosphere, extending from the ionosphere down to the Earth’s surface. These disturbances result in magnetic fluctuations and transient variations that give rise to various perturbations such as navigation systems perturbations or geomagnetically induced currents (GICs) at ground level among others. Surprisingly, localized and intense magnetic variations have also been observed during relatively quiet solar wind conditions.
In this study, we analyze data in the sub-auroral regions collected from ground-based instruments, SuperDARN radars and magnetometer stations (SuperMag, Mag-Swe-Dan) combined with AMPERE data. We investigate SuperDARN data to automatically detect sub-auroral polarization streams (SAPS) features. The “SAPS algorithm” screened SuperDARN data (all radars included) over 3 years, from 2010 to 2012 for velocity higher than 500 m/s. Based on AMPERE data, these automatically detected potential SAPS features are filtered to restrict the dataset to the sub-auroral region only. We then related these SAPS observations to dB/dt spikes during the same period of times.
Our study reveals some interesting patterns during certain events, like unexpected changes in the magnetic field happening at the same time in different places. Even though these events and dB/dt spikes have individually been studied before, many aspects in both fields remain unknown. Our research highlights the importance of understanding these localized dB/dt spikes with higher-resolution data, under various sun conditions, and in conjunction with ionospheric processes. By learning more about these knowledge gaps, we can better understand the behavior of space weather and their potential applications.
Author(s): Maria Hamrin, Audrey Schillings, Hermann Opgenoorth, Sara Nesbit-Östman, Eva Krämer, Juan C. Araújo C, Lisa Baddeley, Herbert Gunell, Timo Pitkänen, Jesper Gjerloev, Robin Barnes
Umeå University, Sweden; Umeå University, Sweden; Umeå University, Sweden; Umeå University, Sweden; Umeå University, Sweden; Umeå University, Sweden; The University Centre in Svalbard; Umeå University, Sweden; Shandong University, China; Johns Hopkins University-Applied Physics; Johns Hopkins University-Applied Physics
Abstract: Rapid variations in the magnetic field (dB/dt) can cause Geomagnetically Induced Currents (GICs) that can be harmful for human infrastructure. The risk for dB/dt spikes is known to be high during geomagnetic storms and substorms, but less is known about the spike occurrence during non-stormy times. We use data from ground-based globally covering SuperMAG magnetometers from the years 1985–2021, and we investigate the spike occurrence as a function of magnetic local time, magnetic latitude, and the solar cycle phases during non-stormy times (-15nT<Sym-H<0). We sort our data into substorm intervals (“SUB”) and less active intervals between consecutive substorms (“nonSUB”). We find that spikes are commonly occurring in both SUBs and nonSUBs during non-stormy times. This implies a risk for infrastructure damage also during non-stormy times, especially when several spikes occur nearby in space and time, potentially causing additional weathering in the infrastructure. We find that spikes are more common in the declining phase of the solar cycle, and that the occurrence of SUB spikes propagates from a midnight to a morning hotspot with ∼10 min in magnetic local time for each minute in universal time.
Author(s): Karl Laundal, Andreas S. Skeidsvoll, Spencer Hatch, Michael Madelaire, Fasil Tesema, Beatrice Popescu Braileanu
University in Bergen; University in Bergen; University in Bergen; University in Bergen; University in Bergen; University in Bergen
Abstract: Most ionospheric models are electrostatic, assuming Faraday’s law to be zero, which neglects the dynamic variations in the magnetic field. Instead, magnetic field variations are described as transitions between steady states. Consequently, the dynamic response of the ionosphere, which causes potentially hazardous magnetic field variations on the ground, is poorly understood. We present a new global model and simulation results that describe how the ionosphere dynamically responds to magnetospheric forcing and neutral wind. This model elucidates how magnetic field perturbations propagate through the ionosphere and produce magnetic field disturbances on the ground. By using the B,v paradigm instead of the traditional E,j paradigm, our approach treats the magnetic field and plasma velocity as primary variables, providing a novel perspective in ionospheric physics.
Author(s): Federico Gasperini
Orion Space Solutions
Abstract: Global-scale waves (GSWs) with periods between about 8 hours to 4 days (e.g., tides, planetary waves, and ultra-fast Kelvin waves) play a crucial role in connecting planetary-scale weather patterns in the lower atmosphere with the “space weather” of the ionosphere-thermosphere (IT) system. GSWs are periodic in time and longitude and interact with the lower IT region (ca. 100-150 km) to generate electric fields that map to higher altitudes and redistribute plasma in the ~200-1000 km region. Emerging evidence suggests that nonlinear interactions among GSWs and the resulting secondary waves represent an important source of “complexity” in the IT system. A second level of complexity occurs when the GSW spectrum interacts nonlinearly with an ionospheric plasma that varies quasi-periodically with the solar flux and is embedded in the spatially-dependent main magnetic field. In this talk, we will review some of the critical aspects related to these complexities and present recent research developments employing neutral winds and ion density observations from the ICON observatory, 3-D global electron density from the COSMIC-2 Global Ionospheric Specification (GIS) assimilation model, and neutral temperatures from the TIMED/SABER instrument.
Author(s): Jordi Vila-Pérez, Ngoc Cuong Nguyen, Jaume Peraire
Massachusetts Institute of Technology; Massachusetts Institute of Technology; Massachusetts Institute of Technology
Abstract: Space weather shapes the dynamics of the ionosphere-thermosphere system and has a critical influence on satellite-based technologies. Solar storms and geomagnetic activity can cause sudden variations in atmospheric density and electron content that compromise trajectory prediction and collision avoidance for satellites, or interfere with communication and navigation systems. The pursuit for advanced methods to estimate the state of the upper atmosphere is therefore foundational for ensuring the efficacy of such space-based applications.
In this context, physics-based models of the ionosphere and thermosphere have been introduced to overcome the limited predictive capabilities of empirical models, especially under rare or unprecedented events. However, they are computationally expensive, as they require solving large systems of equations describing the conservation of mass, momentum, energy and charge of multiple neutral and ion species, together with electrons
This talk introduces a novel physics-based model of the ionosphere-thermosphere system based on the discontinuous Galerkin (DG) method, available open-source within the computational code Exasim. The DG discretization provides high-order accuracy in a computationally efficient strategy, with excellent scalability properties on parallel GPU systems. The model describes an ionosphere-thermosphere system in non-hydrostatic equilibrium and considers the advection of most ion species. The external activity of the Sun is accounted via photoionization and through geomagnetic interactions. The high-latitude electric potential is represented by means of an open-closed field line boundary approximation. The computational approach features implicit time integration, via diagonally-implicit Runge-Kutta schemes, which allows an effective treatment of chemical reactions.
The presentation will introduce different test cases in order to assess the accuracy of the approximation in the prediction of thermospheric and ionospheric quantities of interest. The results will be validated against satellite and ground-based observational data. A 1D model will be presented, which will be used to explore the model integration with data-driven methodologies, in particular with the development of a data-assimilative tool for forecasting purposes.
Author(s): Denny M. Oliveira, Edtyhia Zesta
NASA/GSFC; NASA/GSFC
Abstract: Interplanetary shock impact angles have been shown to be an important feature controlling the subsequent geomagnetic activity triggered by shocks. In general, more head-on shock impacts enhance geospace currents more effectively leading, in turn, to enhanced phenomena related to space weather effects such as ultra-low frequency waves in the magnetosphere, field aligned currents that connect the magnetosphere-ionosphere system, and geomagnetically induced currents in ground conductors. In this work, we present for the first time a study of Polar Cap (PC) index response to shocks with different inclinations. Our IP shock list contains ~ 620 events from January 1995 to May 2024. The PC index is highly correlated with the azimuthal interplanetary electric field which is controlled, e.g., by the Khan and Lee (KL) coupling function. We first focus on the northern PC index (PCN) recorded at the Qaanaaq/Thule (THU) station in Greenland (77.47oN, 69.23oW). PCN index data is available for the whole time span of the shock catalog. Our results indicate that the more frontal the shock, the higher the KL coupling function response and the higher the PCN response, in accordance with many previously published works. We also use PC index data recorded at a southern station, Vostok (VOS) in Antarctica (-78.46oS, 106.84oE), to perform a similar analysis. This index, named PCS, is available from January 1997 onwards. We also find that IP shock impact angles strongly control the PCS response. However, a careful comparison of PCN and PCS response with the same number of events (>500 events from January 1997 onwards) shows that the southern response is slightly higher than the northern response, particular for nearly frontal shocks. Such results are at odds with previous results, namely that the northern hemisphere receives slightly more magnetospheric energy in comparison to the southern hemisphere during active times due to a larger offset between the magnetic and geographic poles in the south. We then suggest that such disagreement may have arisen from the quality of the PCS data. Thus, we call for a further revision of the PCS index for the enhancing of its quality for its future use by the space weather community.
Author(s): Lorenzo Biasiotti, Stavro Ivanovvski, Lorenzo Calderone, Giovanna Jerse, Monica Laurenza, Dario Del Moro, Francesco Longo, Christina Plainaki, Maria Federica Marcucci, Anna Milillo, Marco Molinaro, Chiara Feruglio
Department of Physics, University of Trieste, Trieste, Italy; INAF – Trieste Astronomical Observatory; Trieste Astronomical Observatory, INAF, Trieste, Italy; Trieste Astronomical Observatory, INAF, Trieste, Italy; Institute for Space Astrophysics and Planetology, INAF, Rome, Italy; Department of Physics, University of Rome “Tor Vergata”, Rome, Italy; Department of Physics, University of Trieste, Trieste, Italy; Italian Space Agency, Rome, Italy; Institute for Space Astrophysics and Planetology, INAF, Rome, Italy; Institute for Space Astrophysics and Planetology, INAF, Rome, Italy; Trieste Astronomical Observatory, INAF, Trieste, Italy; Trieste Astronomical Observatory, INAF, Trieste, Italy
Abstract: Kelvin-Helmholtz (KH) and tearing mode (TM) instabilities are one of the most important mechanisms of solar wind energy, momentum and plasma transport within the magnetosphere.
To investigate the conditions under which KHTM instabilities occur in the Earth environment it is fundamental to combine simultaneous multipoint in situ measurements and MHD simulations. We analyzed data from the THEMIS and Cluster spacecraft considering two Space Weather events starting with an M2.0 flare event (Case-1) that occurred on 21 June 2015 and the most-intensive flare (X9.3) of solar cycle 24 that occurred on 6 September 2017 (Case-2).
Our analysis utilized a 2D MHD model for incompressible and viscous flow. The results from Case-1 indicate the presence of KH and TM instabilities (Fig. 1), suggesting existence of observed low-amplitude oscillations at the nose of the magnetopause. However, the MHD simulations for Case-2 did not show any evidence of KH vortices, but did reveal the presence of “magnetic island” structures during a low-shear condition (Fig. 2). The reconnection rate derived from the observations is compared with the computed one in the presence of developed instabilities inside the Earth’s magnetopause.
This work has been published in Frontiers (Biasiotti L, et al. (2024), Front. Astron. Space Sci. 11:1395775.doi: 10.3389/fspas.2024.1395775).
SWR4.2 Wed 6/11 09:00-10:15, room C2A – Mondego
Author(s): Wojciech Miloch, Yaqi Jin, Daria Kotova, Alan Wood, Gareth Dorrian, Lucilla Alfonsi, Luca Spogli, Rayan Imam, Eelco Doornbos, Kasper van Dam, Mainul Hoque, Jaroslav Urbar
Department of Physics, University of Oslo, Oslo, Norway; Department of Physics, University of Oslo, Oslo, Norway; Department of Physics, University of Oslo, Oslo, Norway; Space Environment and Radio Engineering (SERENE) group, University of Birmingham, Birmingham, UK; Space Environment and Radio Engineering (SERENE) group, University of Birmingham, Birmingham, UK; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; The Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands; The Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands; German Aerospace Center (DLR), Neustrelitz, Germany; Institute of Atmospheric Physics CAS, Prague, Czech Republic
Abstract: Variability and structuring of the Earth’s ionosphere depends on forcing from above and below. Coupling of the ionosphere with the Earth’s magnetosphere and the solar wind, as well as to the neutral atmosphere, make the phenomena in the ionosphere highly dynamic and the state of ionosphere depends on many external variables. Thus, modelling of the whole ionosphere and capturing its full dynamic range considering all spatiotemporal scales is challenging.
Measurements by satellites in the low Earth orbits can form a basis for ionospheric models where different spatiotemporal scales can be addressed. These results can significantly contribute to our efforts within space weather modeling and monitoring. The European Space Agency’s Swarm mission is a constellation of three identical satellites in polar orbits, which has provided high-quality in situ data for more than ten years. This dataset allows for both space weather and climatology studies. Recently, with the Swarm-VIP models it was demonstrated that the Swarm mission can successfully address ionospheric variability at larger scales in relation to geophysical proxies.
The new Swarm-VIP-Dynamic project started in early 2024 and it focuses on the variability, irregularities, and predictive capabilities for the dynamic ionosphere, including short time scales. In this project, we develop a suite of models for capturing the ionosphere structuring and dynamics at various spatiotemporal scales. In addition to the Swarm data, we use datasets from other satellites and ground-based instruments for validation and to explore the added value of space instrumentation with various observation and sampling characteristics. We also test the feasibility of the models to be used in a real-time environment. We present recent results from the Swarm-VIP-Dynamic project, its model concepts, as well as prospects of further development in the context of space weather and predicting ionospheric space weather effects.
Author(s): Juan Andrés Cahuasquí, Mainul Hoque, Norbert Jakowski, Dmytro Vasylyev, Stephan Buchert, Grzegorz Nykiel, Martin Kriegel, Paul David, Youssef Tagargouste, Lars Tøffner-Clausen, Jens Berdermann
German Aerospace Center DLR; German Aerospace Center DLR; German Aerospace Center DLR; German Aerospace Center DLR; Swedish Institute of Space Physics (IRF); Gdansk University of Technology; German Aerospace Center DLR; German Aerospace Center DLR; German Aerospace Center DLR; Technical University of Denmark; German Aerospace Center DLR
Abstract: The successful completion of the Swarm DISC project “Monitoring of Ionospheric Gradients at Swarm (MIGRAS)” has led to the development of two new data products – the electron density gradient ionosphere index (NeGIX) and the total electron content gradient ionosphere index (TEGIX) –, for characterizing the perturbation degree of the topside ionosphere. NeGIX estimates spatial electron density gradients using L1 Langmuir probe measurements, and TEGIX estimates spatial TEC gradients using L2 GNSS Precise Orbit Determination (POD) data of Swarm. Unlike existing Swarm ionospheric indices based on single satellite measurements (e.g. the ionospheric bubble index IBI, or the ionospheric plasma irregularities index IPIR), the two new products benefit from the combination of spatially- and temporally-related measurements from Swarm satellites Alpha (A) and Charlie (C) to estimate ionospheric gradients in spatial scales of up to 200 km. This provides a better insight into ionospheric irregularities and structures not only along the satellites’ orbits, but also in the zonal direction.
In this work, we present the results of a validation study of the Swarm data products NeGIX and TEGIX based on more than 10 years of Swarm data availability. The long-term data analysis enables us to examine the applicability of the newly-developed indices to characterize time- (seasonal, diurnal) and spatial-dependent ionospheric features such as the equatorial crests, mid-latitude trough, or the South Atlantic Anomaly. On the other hand, analysis of concrete events of severe geomagnetic activity, such as the St. Patrick’s Day storm of 2015 or the geomagnetic storm on May 10th and 11th of 2024, allows us to evaluate their applicability to serve as reliable proxies for the identification of perturbations that can threat the availability and functionality of radio systems for telecommunication, navigation and remote sensing. We compare the performance of the MIGRAS products versus other existing ionospheric indices (e.g. the ground-based GIX, IBI or IPIR) that describe small- to mid-scale irregularities, such as ionospheric plasma bubbles. Beyond the scientific and applicable purposes of this work, our validation study aims also at endorsing the operational availability of NeGIX and TEGIX among the unique and broad spectrum of Swarm data services for space weather research.
Author(s): Martin Cafolla, Sandra Chapman, Sandra Chapman, Sandra Chapman, Nick Watkins, Nick Watkins, Xing Meng, Olga Verkhoglyadova
Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, UK; Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, UK; Department of Mathematics and Statistics, University of Tromso, Norway; International Space Science Institute, Bern, Switzerland; Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, UK; Grantham Research Institute, London School of Economics and Political Science, London, UK; School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China; Jet Propulsion Laboratory, California Institute of Technology, USA
Abstract: Space weather events affect GPS positioning and timing, resulting in issues with navigation andcommunication. It is therefore important to monitor such events, which can be done through ground GNSS observations of Total Electron Content (TEC). Our study uses 20 years of TEC data from the Jet Propulsion Laboratory (JPL) compiled from over 200 globally distributed ground stations to create 15-minute cadence Global Ionospheric Maps (GIMs) with a spatial resolution of 1◦ × 1◦ in longitude/latitude. Maps are converted to a geomagnetic coordinate frame that fixes the sub-solar point, where the Sun is directly overhead, at a constant longitude λ = 0◦ and defines a basis incorporating the Earth’s dipole axis and sub-solar vector. A threshold of the top 1% of TEC measurements is taken to isolate large-scale TEC enhancements, known as High Density Regions (HDRs). With image processing tools in python we detect and track these HDRs over 2 solar cycles to obtain a set of labelled, contiguous space-time TEC HDRs. We can determine the locations of these HDRs, how long they last and their size/brightness. Our analysis detects, labels and tracks HDR origin, path, areas, TEC intensities and duration. Analysis of this extensive data set shows a difference in behaviour between continental-scale (∼ 10^7km^2) and smaller enhancements and geomagnetic responses to their trajectories. We also show seasonal fluctuations in TEC enhancements through time-series analysis, picking out key frequencies seen in Earth/solar rotation. Due to results being statistical in nature, they can differentiate reproducible trends in the data which have the potential to be seen in predictive models for ionospheric enhancements within the observed spatial/temporal scales.
Author(s): Alan Wood, Gareth Dorrian, Ben Boyde, Hannah Trigg, Richard Fallows, Maaijke Mevius
University of Birmingham, UK; University of Birmingham, UK; University of Birmingham, UK; University of Birmingham, UK; Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory, UK; ASTRON – The Netherlands Institute for Radio Astronomy
Abstract: The Low Frequency Array (LOFAR) is one of the most advanced radio telescopes in the world. When radio waves from a distant astronomical source traverse the ionosphere, structures in this plasma affect the signal. The high temporal resolution available (~10 ms), the range of frequencies observed (10-90 MHz & 110-250 MHz) and the large number of receiving stations (currently 52 across Europe) mean that LOFAR can also observe the effects of the midlatitude and sub-auroral ionosphere at an unprecedented level of detail.
The Space Environment and Radio Engineering (SERENE) research group at the University of Birmingham (UoB) are leading a four-year research programme to determine the morphology, origin and evolution of plasma structures inferred from observations made using LOFAR, and to establish the implications of these observations for Earth system science.
Multiple observational case studies have been undertaken. These show substructure within a sporadic-E layer (Wood et al., 2024), substructure within a Medium Scale Travelling Ionospheric Disturbance (TID) (Dorrian et al., 2023), a Small Scale TID (Boyde et al., 2022) and symmetric quasi-periodic scintillations (Trigg et al., 2024). The small-scale sizes of many of these features (kilometres to tens of kilometres) implies a local source, either due to instability processes in the mid-latitude ionosphere or due to drivers from below. A methodology has been developed to determine the propagation direction, speed and amplitude of waves observed in the ionosphere (Boyde et al., 2024) and a climatology has been created using this method. The waves observed primarily propagate in the opposite direction to the prevailing wind, strongly suggesting that the structures observed are the ionospheric manifestation of upward propagating Atmospheric Gravity Waves (Boyde et al., in preparation). This indicates that the majority of the plasma structures observed in this climatology are driven by variability lower in the terrestrial atmosphere.
This work is supported by the Leverhulme Trust under Research Project Grant RPG-2020-140.
References
Boyde, B. et al. (2024). Wavelet analysis of differential TEC measurements obtained using LOFAR. Radio Science, 59, doi:10.1029/2023RS007871
Boyde, B. et al. (2022). Lensing from small-scale travelling ionospheric disturbances observed using LOFAR.” J. Space Weather Space Clim., 12, doi:10.1051/swsc/2022030
Dorrian, G. D. et al. (2023). LOFAR observations of substructure within a traveling ionospheric disturbance at mid-latitude, Space Weather, 21, doi:10.1029/2022SW003198
Trigg, H. et al. (2024). Observations of high definition symmetric quasi-periodic scintillations in the mid-latitude ionosphere with LOFAR. J. Geophys. Res., 2023JA032336, under review.
Wood, A. G. et al. (2024). Quasi-stationary substructure within a sporadic E layer observed by the Low Frequency Array (LOFAR), J. Space Weather Space Clim., 230077, under review.
Author(s): Vanina Lanabere, Andrew P. Dimmock, Stephan Buchert, Yuri V. Khotyaintsev, Octav Marghitu, Louis Richard
Swedish Institute of Space Physics; Swedish Institute of Space Physics; Swedish Institute of Space Physics; Swedish Institute of Space Physics; Institute of Space Science; Swedish Institute of Space Physics
Abstract: Earthward bursty bulk flows (BBFs) occurring in the mid-magnetotail are responsible for most plasma transport from the magnetotail to the inner-magnetosphere, which are coupled to the high-latitude ionosphere via Field-Aligned Current (FAC) systems. By combining ionospheric observations over about 10 years from the Swarm constellation with magnetospheric missions, especially the Magnetospheric Multiscale (MMS) Mission, we study whether and how the FAC system responds to BBFs. In this study, we use a database of approximately 2000 BBFs detected during the tail seasons of MMS between 2017 and 2021, which are carefully mapped onto the ionosphere using a set of Tsyganenko models. The footpoints obtained with these models usually significantly differ from each other and depend strongly on the dipole tilt angle (angle between the dipole axis and the GSM z-axis), solar wind and geomagnetic conditions. However, the statistical location of the BBF footpoint reveals a consistent pattern between 65° and 75° magnetic latitude and between 20 and 04 MLT, with a maximum in the pre-midnight sector. We compare the footpoint locations with statistical maps of FACs during intervals when MMS magnetotail data are available. This study aims to provide a deeper understanding of FAC behaviour by examining variations in current density, structural distortions, and spatial scale. Additionally, the identification of case studies complements the statistical findings and provides a better understanding of spatially localised geomagnetic perturbations, which are increasingly recognized as significant contributors to geomagnetically induced currents. These results will enhance our understanding of FACs and which are one of the primary magnetosphere-ionosphere coupling mechanisms.
SWR4.3 Thu 7/11 09:00-10:15, room C2A – Mondego
Author(s): sean bruinsma, sophie laurens
GET-CNES, Space Geodesy Office; GET-CNES, Space Geodesy Office
Abstract: Atmospheric density models are used in satellite orbit determination and prediction programs to compute the atmospheric drag force. They represent temperature and (partial) density as a function of altitude, latitude, local solar time, day-of-year, and parameters related to the state of atmospheric heating due to solar EUV emissions (with proxies F10.7 or F30) and solar wind (with proxies Kp or Hp).
DTM_nrt, which uses exospheric temperature corrections inferred from observed densities essentially for debiasing, was developed in 2013 in the framework of the European Union’s 7th Framework programme ATMOP. The temperature corrections were then predicted 1-3 days out using an artificial neural network. The background model used at the time was DTM2009. We have started the development of an updated DTM_nrt, which uses the more precise DTM2020 as background model, since near real time total density data may become available in the foreseeable future.
The first part of the project consists in calculating the temperature corrections to DTM2020 based on densities of CHAMP, GRACE, GOCE, Swarm-A, GRACE-FO and Stella, verify their consistency, and develop a method to make them consistent if needed. In 2013, daily temperature corrections were calculated. More frequent corrections are required to improve the predictions and the highest achievable cadence will be tested in this study. The ultimate forecast performance of DTM_nrt is quantified by means of comparing with the density data after exospheric temperature correction, i.e. the performance in case of perfect prediction of such corrections. These ultimate results will be compared with assessment results of DTM2020 in order to estimate the gain in precision thanks to the data assimilation. The second part of the project consists in the actual update of the neural network model. This presentation shows the results for the first part of the project.
Author(s): Xin Wang, Bingxian Luo, Siqing Liu
National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China.; National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China.; National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China.
Abstract: Thermospheric neutral mass density is essential for the calculation of atmospheric drag, which is the main cause of the orbit decay for low-Earth-orbit (LEO) satellites. An recent example of space weather affecting human space activity occurred on 3–4 February 2022, associated with two successive moderate geomagnetic storms. The thermospheric mass density enhancement of about 50% at the height of ~210 km, led to 38 Starlink satellites being destroyed before they were lifted to a higher orbit.
During geomagnetic storms, the Joule heating has a strong impact on neutral mass density. In this work, we statistically investigate 265 geomagnetic storms to explore the response of thermospheric density to Joule heating from 2002 to 2008. We obtain the density enhancements from Challenging Minisatellite Payload (CHAMP) and the Gravity Recovery and Climate Experiment (GRACE) satellites, and we also calculate Joule heating from the Defense Meteorological Satellite Program (DMSP) spacecraft and the Weimer electric potential model. The results show that the thermospheric density delays Joule heating during geomagnetic storms. The time lag is about 0-2 hrs during weak and moderate storms, while it is 3-5 hrs for intense storms. In addition, Joule heating can affect the density enhancement at higher latitude regions. Thermospheric model, the NRLMSISE-00 model, commonly underestimates the neutral density during geomagnetic storms. Hence, we use the temporal relationship of thermospheric density with geomagnetic activity indices and Joule heating as calibration for the NRLMSISE-00. The calibrated NRLMSISE-00 model results can better simulate the storm-time thermospheric density, with the Mean Relative Error (MRE) between observation and model decreasing from 40% to 10%.
Author(s): Myrto Tzamali, Alexi Glover, Juha-Pekka Luntama
Research Fellow (ESA-ESOC); Space Weather Service Coordinator (ESA-ESOC); Head of Space Weather Office (ESA-ESOC)
Abstract: Thermospheric densities are crucial for orbit prediction, satellite tracking, and investigating the environment in which Low Earth Orbit (LEO) satellites operate. Deriving thermospheric densities from accelerometer measurements onboard satellites is currently the only in-situ data source available at altitudes below 600 km. These measurements are susceptible to various errors related to the calibration and thermal sensitivity of the accelerometer, and the mismodeling of the non-gravitational forces acting on the satellite, such as Solar Radiation Pressure, thermal Radiation pressure, and drag. In this study, we investigate the error sources in the thermospheric densities derived from the Swarm and GRACE-FO LEO missions during their common operational years from 2018 to 2024, focusing on their strong dependence on local time and latitude. We also analyze the highest fluctuations of the residual densities observed at the poles and during terminator crossings, especially during the solar minimum when the drag acting on the satellite is minimal. Additionally, we compare the discrepancies in the datasets from the two missions during various geomagnetic storms, noting that during this period, the altitudes of the missions differ by almost 50 km.
Author(s): Georgios Balasis, Constantinos Papadimitriou, Adamantia Zoe Boutsi, Omiros Giannakis
National Observatory of Athens; National Observatory of Athens; National Observatory of Athens; National Observatory of Athens
Abstract: In November 2023, the ESA Swarm constellation mission celebrated 10 years in orbit, offering one of the best-ever surveys of the topside ionosphere. Among its achievements, it has been recently demonstrated that Swarm data can be used to derive space-based geomagnetic activity indices, like the standard ground-based geomagnetic indices, monitoring magnetic storm and magnetospheric substorm activity. Given the fact that the official ground-based index for the substorm activity (i.e., the Auroral Electrojet – AE index) is constructed by data from 12 ground stations, solely in the northern hemisphere, it can be said that this index is predominantly northern, while the Swarm-derived AE index may be more representative of a global state, since it is based on measurements from both hemispheres. Recently, many novel concepts originated in time series analysis based on information theory have been developed, partly motivated by specific research questions linked to various domains of geosciences, including space physics. Here, we apply information theory approaches (i.e., Hurst exponent and a variety of entropy measures) to analyze the Swarm-derived magnetic indices around intense magnetic storms. We show the applicability of information theory to study the dynamical complexity of the upper atmosphere, through highlighting the temporal transition from the quiet-time to the storm-time magnetosphere, which may prove significant for space weather studies. Our results suggest that the spaceborne indices have the capacity to capture the same dynamics and behaviors, with regards to their informational content, as the traditionally used ground-based ones. A few studies have addressed the question of whether the auroras are symmetric between the northern and southern hemispheres. Therefore, the possibility to have different Swarm-derived AE indices for the northern and southern hemispheres respectively, may provide, under appropriate time series analysis techniques based on information theoretic approaches, an opportunity to further confirm the recent findings on interhemispheric asymmetry. Here, we also provide evidence for interhemispheric energy asymmetry based on the analyses of Swarm-derived auroral indices AE North and AE South.
Author(s): Antonio Guerrero
University of Alcala
Abstract: The geomagnetic field is one of the oldest indicators of the effectiveness of space weather events but progress in the monitoring and forecasting of geomagnetic disturbances has not improved considerably since long ago. The science of the magnetosphere-ionosphere-thermosphere system have taken their chances to help in the improvement of space weather but usually using an old-fashion assessment of the geomagnetic field through global indices instead of local ones.
We present here a product that unites several aspect or real needs in space weather. World maps of local geomagnetic disturbances for low and mid latitudes (regions where most of end-users develop their activities worldwide) able to run with real time data. The map indicates the disturbances in a discrete (0 to +- 9) colour scheme (that is accessible) using a similar scale to that used by the well-known Kp index. Added to its capability to run in real-time and its easy-to-understand colour scale, the map is capable to offer a resolution of 1 minute (as low as the data input). The map, at current stage of development, uses data from INTERMAGNET observatories that are processed using the Local Disturbance index (LDi), a procedure developed at University of Alcala to obtain an indication of the geomagnetic disturbances.
We show the advantages of using such a product in recognizing negative, but also positive, geomagnetic disturbances worldwide which can go unnoticed using traditional means. We hope this product will fill a gap and help improve understanding of the Magnetosphere-Ionosphere-Thermosphere system.
Posters
Posters I Display Tue 5/11 – Wed 6/11, room C1A – Aeminium
Authors in attendance: Tue 5/11 10:15–11:30, 15:15-16:15; Wed 6/11 10:15–11:30
Author(s): Mostafa Ahmed, Mohamed Omar, Hala Gomaa, Ayman Mahrous
Helwan University; Helwan University; Helwan University; E-JUST
Abstract: This research presents a comprehensive 11-year statistical study (2010-2020) of ionospheric gravity waves induced by magnetic storms. We utilize all-sky camera images of airglow from the MacDonald Observatory to investigate these atmospheric disturbances. The study aims to discern patterns and behaviors in the ionospheric gravity waves associated with magnetic storms, contributing to a deeper understanding of their dynamics and impacts.
Magnetic storms are known to disrupt the Earth’s magnetic field and can significantly affect the ionosphere. These disturbances can lead to the generation of gravity waves in the upper atmosphere. Our work focuses on identifying and characterizing these gravity waves in the ionosphere. The study period spans 11 years, allowing for a robust analysis of various atmospheric conditions and their relationship to gravity wave occurrences.
The methodology involves extensive data preprocessing, feature extraction, and the application of advanced statistical techniques. By analyzing a large dataset of airglow images, we aim to identify gravity wave signatures during magnetic storms. This approach holds promise for improved space weather predictions and a more profound understanding of upper atmospheric phenomena.
This research’s outcomes are expected to provide valuable insights into the behavior of ionospheric gravity waves under the influence of magnetic storms. Furthermore, this study may contribute to the broader field of space weather research, offering tools to enhance our understanding of the Earth’s upper atmosphere dynamics and predictability during magnetic storms.
Author(s): Habtamu Marew Alemu, Kateryna Aksonova, Jaroslav |Chum
Institute of Atmospheric Physics of the Czech Academy of Sciences; Institute of Atmospheric Physics of the Czech Academy of Sciences; Institute of Atmospheric Physics of the Czech Academy of Sciences
Abstract: We present a storm time Ionosphere-Thermosphere profile to the January 14, 2022 Moderate Storm under Solar Minimum condition. ICON satellite observations (ion density and neutral wind speed) are used for the storm time analysis. The study has been conducted using ionosphere-thermosphere parameters from a bout 85-600 km altitude which allows to look storm responses of different layers of ionosphere unlike the most common single-layer analysis. The results show that the storm caused ion density enhancement and spread (irregularity) structure. The storm effect is witnessed at all longitudinal sector within -120 to 420 latitude. Westward wind speed of up to 400m/s is recorded during the main phase of the storm and eastward wind speed of up to 300m/s are observed. The storm caused disturbances at all altitudes considered; 160, 200, 250 and 300 km and a pronounced effect is observed at an altitude of 160 km. Generally, ICON observations are able to indicate how the ionosphere is influenced by the geomagnetic storms.
Author(s): Simone Mestici, Fabio Giannattasio, Paola De Michelis, Francesco Berrilli, Giuseppe Consolini
Università di Roma La Sapienza; Istituto Nazionale di Geofisica e Vulcanologia; Istituto Nazionale di Geofisica e Vulcanologia; Università di Roma Tor Vergata; INAF-Istituto di Astrofisica e Planetologia Spaziali
Abstract: Space plasma turbulence plays a relevant role in several plasma environments, such as solar wind and the Earth’s magnetosphere–ionosphere system, and is essential for describing their complex coupling. This interaction gives rise to various phenomena, including ionospheric irregularities and the amplification of magnetospheric and ionospheric currents. The structure and dynamics of these currents have relevant implications, for example, in studying ionospheric heating and the nature of electric and magnetic field fluctuations in the auroral and polar environments. In this study, we investigate the nature of small-scale fluctuations characterizing the ionospheric magnetic field in response to different geomagnetic conditions. We use high-resolution (50 Hz) magnetic data from the ESA’s Swarm mission, collected during a series of high-latitude crossings, to probe the scaling features of magnetic field fluctuations in auroral and polar cap regions at spatial scales still poorly explored. Our findings reveal that magnetic field fluctuations in field-aligned currents (FACs) and polar cap regions across both hemispheres are characterized by different scaling properties, suggesting a distinct driver of turbulence. Furthermore, we find that geomagnetic activity significantly influences the nature of energy dissipation in FAC regions, leading to more localized filamentary structures toward smaller scales.
Reference Article: 10.3390/rs16111928
Author(s): Susanna Bekker, Ryan Milligan
Queen’s University Belfast; Queen’s University Belfast
Abstract: The Earth’s ionosphere is subject to seasonal, daily, and sporadic variations associated with changes in solar and magnetic activity. The problem of studying the response of ionospheric layers to natural disturbances caused by solar radiation variations in different wavelength ranges is still open and is being actively developed at present. Variations in X-ray and UV irradiance during solar flares lead to a noticeable increase in the electron concentration in the illuminated part of the Earth’s ionosphere. One of the most valuable tools for studying solar-terrestrial connections is Global Navigation Satellite System (GNSS). Due to the large amount of experimental data accumulated by GNSS, the total electron content (TEC) response to the impulsive phase of a solar flare has been studied quite well. At the same time, recent studies have shown that approximately 40% of X-class flares have second strong peak of warm coronal emission (which is called “EUV late phase”), whose influence on the ionization of ionospheric layers is not yet clear. A combined analysis of successive solar emissions and the caused electron concentration changes made it possible to numerically estimate the ionospheric response to the impulsive and late phases of the X2.9 (3 November 2011), X2.4 (23 October 2012), and X2.0 (25 April 2014) solar flares which are characterized by different spectrum and localization on the solar disk. It has been demonstrated that the TEC increment during the EUV late phase of a limb flare can exceed the response to its impulsive phase and reaches 0.6-0.7 tecu. The TEC response to the relatively weak emissions of the EUV late phase of a disk flare depends on the flare spectrum and is 30–50 % of the TEC increase during the impulsive phase. The energy of the EUV late phase of more powerful event than those considered in this work can be much higher, so the obtained result indicates a serious need to consider the late emission of warm coronal lines when modeling and forecasting the ionospheric response to variations in solar radiation. The results obtained demonstrates the great promise of synchronous analysis of solar spectrum radiation variations and experimental measurements of ionospheric parameters for the study of solar-terrestrial connections.
Author(s): Dr. Awuor Adero, Prof. Paul Baki, Prof. Geeta Vichare, Dr. Pierre Cilliers, Dr. Chao Xiong, Dr. Peter Kotze
Technical University of kenya; Technical University of kenya; Indian Institute of Geomagnetism, New Panvel, Navi Mumbai, 410 218, India; SANSA; GFZ German Research Centre for Geosciences, Telegrafenberg, 14473, Potsdam, Germany; SANSA
Abstract: Present paper studies Field aligned currents (FACs) estimated by employing Ampere’s law to the magnetic field recorded by CHAMP satellite during 24 geomagnetic storms. Low-pass filtered FACs with a cutoff period of 20 s (scale size~150 km) are used to determine FAC range, which is defined as a peak-to-peak amplitude of FAC density. Thus we are considering only the strongest positive and negative FACs emerging either from Region 1, Region 2, Region 0, or substorm current wedge systems. It is known that the FACs significantly depend on the highly variable solar wind (SW) and interplanetary magnetic field (IMF) conditions and also on the processes internal to magnetospheric-ionospheric system such as substorm. The correlation analysis carried out here shows that sometimes the FAC range, correlates well with SymH, AsyH, AsyD, AL, am and Kp indices (>95% significance), but not always. The variation of the FAC range with magnetic local times shows distinctly different patterns during southward and northward IMF conditions, with peaks near dawn-dusk during southward IMF and near local noon-midnight during northward IMF. These results are in agreement with the earlier reports. However, the seasonal dependence reveals that the noon time peak is essentially associated with the summer season. We have determined a new parameter called ‘occurrence rate of FAC range >1 μA/m2’ and examined it
under various solar wind and IMF conditions. It is found that the probability of FAC range >1 μA/m2 have a clear dependence on the clock angle, suggesting more frequent intensifications during southward IMF. Clear linear dependence on the cone angle demonstrates higher occurrence probability of FAC range> 1 μA/m2 when the IMF is perpendicular to the Sun-Earth line (cone angle nearing 90 deg). All these results based on the newly defined parameters such as FAC range and probability of FAC range >1 μA/m2, for the storm time mesoscale FAC are consistent with the previous studies. The FAC ranges are found to have a linear dependence on the values of IMF
BY, BYZ, BT and BZ, though saturation is apparent at higher values of the IMF parameters. FAC range shows distinctly different dependence for slow and fast solar wind, suggesting the importance of the composition and properties of SW in controlling the FAC strengths
Author(s): Alemayehu Cherkos
Addis Ababa University
Abstract: This study examined the effect of solar flux (F10.7) and sunspots number (R) on the daily variation of equatorial electrojet (EEJ) and morning/afternoon counter electrojet (MCEJ/ACEJ) in the ionospheric E region across the eight longitudinal sectors during quiet days from January 2008 to December 2013. In particular, we focus on both minimum and maximum solar cycle of 24. For this purpose, we have collected a 6-year ground-based magnetic data from multiple stations to investigate EEJ/CEJ climatology in the Peruvian, Brazilian, West & East African, Indian, Southeast Asian, Philippine, and Pacific sectors with the corresponding F10.7 and R data from satellites simultaneously. Our results reveal that the variations of monthly mean EEJ intensities were consistent with the variations of solar flux and sunspot number patterns of a cycle, further indicating that
there is a significant seasonal and longitudinal dependence. During the high solar cycle period, F10.7 and R have shown a strong peak around equinoctial months, consequently, the strong daytime EEJs occurred in the Peruvian and Southeast Asian sectors followed by the Philippine regions throughout the years investigated. In those sectors, the correlation between the day Maxima EEJ and F10.7 strengths have a positive value during periods of high solar activity, and they have relatively higher values than the other sectors. A predominance of MCEJ occurrences is observed in the Brazilian (TTB), East African (AAE), and Peruvian (HUA) sectors. We have also observed the CEJ dependence on solar flux with an anti-correlation between ACEJ events and F10.7 are observed especially during a high solar cycle period.
Author(s): Natalia Hladczuk, Jose van den IJssel, Pieter Visser, Sabin Anton, Christian Siemes
Delft University of Technology, Delft, The Netherlands; Delft University of Technology, Delft, The Netherlands; Delft University of Technology, Delft, The Netherlands; Delft University of Technology, Delft, The Netherlands; Delft University of Technology, Delft, The Netherlands
Abstract: The characteristics of the neutral thermospheric wind play an important role in understanding the coupling of Earth’s thermosphere and ionosphere and improving models used in space operations. The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite, which operated at an altitude of about 250 km, provided thermosphere crosswind data during most of its operational lifetime from 2009 to 2013.
The accuracy of thermospheric wind data sets derived from satellite accelerations is coupled with aerodynamic and radiation pressure modelling uncertainties. Currently, available GOCE crosswind datasets employ a high-fidelity geometry and aerodynamic model representation together with a new setting of the aerodynamic energy accommodation coefficient αE = 0.82. Despite that, a few possible shortcomings have been identified in existing datasets. It has been shown that current GOCE winds present a significant offset compared to other datasets, especially on the duskside. Moreover, there are characteristic jumps in the crosswind data as the satellite enters and exits eclipses.
This presentation will address these shortcomings and focus on improving GOCE crosswind products by enhancing our solar radiation pressure modelling and introducing thermal emission modelling. In our approach to solar radiation pressure modelling, we employed the high-fidelity geometry model of GOCE, augmented with formerly optimised parameters describing the thermo-optical surface properties. We then used ray-tracing techniques on the augmented geometry model to derive the force coefficients, accounting for shadowing and multiple reflections.
Considering its large surface area and the extreme temperature variations the GOCE satellite experienced, thermal acceleration plays a pivotal role, especially during penumbra transitions. The GOCE satellite was equipped with thermistors, the majority of which had been placed underneath the satellite’s panels and only a few on the outer surfaces facing cold space. In our approach to calculating the satellite’s thermal emission, we use available in-situ measurements from thermistors on the sun-opposing side. For the remaining panels, we use the similarities between the Swarm, GRACE-FO and GOCE mission design to define thermal parameters.
In this presentation, we will show a comprehensive approach to improving radiation pressure modelling and present enhanced and consistently processed crosswind observations for GOCE. Finally, we will compare results with available wind models as well as previous GOCE datasets.
Author(s): Solomon Otoo Lomotey, Jonas Rodrigues de Souza, Cristiano Max Wrasse, Hisao Takahashi, Diego Barros, Cosme Alexandre Oliveira Barros Figueiredo, José Humberto Andrade Sobral, Fábio Egito, Patrick Essien, Toyese Tunde Ayorinde, Anderson Vestena Bilibio, Nana Ama Browne Klutse
University of Environment and Sustainable Development (UESD); Space Weather Division, National Institute for Space Research (INPE), São José dos Campos SP, Brazil; Space Weather Division, National Institute for Space Research (INPE), São José dos Campos SP, Brazil; Space Weather Division, National Institute for Space Research (INPE), São José dos Campos SP, Brazil; Space Weather Division, National Institute for Space Research (INPE), São José dos Campos SP, Brazil; Space Weather Division, National Institute for Space Research (INPE), São José dos Campos SP, Brazil; Space Weather Division, National Institute for Space Research (INPE), São José dos Campos SP, Brazil; Unidade Acadê,mica de Física, Universidade de Campina Grande, Campina Grande, Brazil; Department of Physics, University of Cape Coast, Cape Coast, Ghana; Space Weather Division, National Institute for Space Research (INPE), São José dos Campos SP, Brazil; Space Weather Division, National Institute for Space Research (INPE), São José dos Campos SP, Brazil; Department of Physics, University of Ghana, Accra, Ghana
Abstract: See the attached file
Author(s): Jocelyn Franck-Patient BOUNGOU POATY, Jean Bienvenu DINGA, Clobite BOUKA BIONA
Université Marien NGOUABI / Institut National de Recherche en Sciences Exactes et Naturelles (IRSEN) / L’Aboratoire de Physique de l’Atmosphère de l’Université Marien NGOUABI/ Université Dénis SASSOU N’GUESSO; Université Marien NGOUABI / Institut National de Recherche en Sciences Exactes et Naturelles (IRSEN) / L’Aboratoire de Physique de l’Atmosphère de l’Université Marien NGOUABI; Université Marien NGOUABI / Institut National de Recherche en Sciences Exactes et Naturelles (IRSEN) / L’Aboratoire de Physique de l’Atmosphère de l’Université Marien NGOUABI/ Université Dénis SASSOU N’GUESSO
Abstract: Dans cette étude, nous avons utilisé les fichiers Rinex, CODG, DCB et YUMA, qui ont servi à représenter les courbes Rinex et CODG TEC des 08 et 09 mars et des 18 et 19 juillet (jours géomagnétiquement calmes) en 2014, permettant d’observer quotidiennement variations de la densité électronique ionosphérique. Nous avons également utilisé des paramètres du vent solaire tels que les champs magnétiques et électriques interplanétaires, Dst et la vitesse, la température, la pression et la densité du vent solaire, pour voir comment ils contribuent aux variations de l’activité ionosphérique. L’analyse des courbes TEC montre qu’elles culminent toutes entre 12h et 16h UTC, quelle que soit la station, la saison ou le jour choisi. Pour le mois de mars, les courbes présentent des maxima plus prononcés que celles du mois de juillet. Par ailleurs, en mars, des variations des courbes TEC ont été constatées qui ne pouvaient s’expliquer par l’ensoleillement. En effet, l’analyse des courbes des paramètres du vent solaire a montré que ceux-ci ont une influence significative sur les variations ionosphériques, notamment celles qui ne peuvent être expliquées par l’ensoleillement. Nous avons également constaté que la pression était un déclencheur de variations de la vitesse et de la température du vent solaire, selon qu’il y avait compression ou dépression. On peut donc affirmer que les paramètres du vent solaire ont une influence remarquable sur les variations ionosphériques observées.
Author(s): Bhupendra Malvi, P. K. Purohit
National Institute of Technical Teachers’ Training & Research, Bhopal – 462002 (M.P.) , India; National Institute of Technical Teachers’ Training & Research, Bhopal – 462002 (M.P.) , India
Abstract: This study investigates the response of the Total Electron Content (TEC) of the ionosphere to the geomagnetic storm that occurred on May 4, 1998, during the 23 solar cycle. The DST index dropped to -205 nT, indicating the extent of disturbance to Earth’s magnetic field. This indicates the severity of the storm. Ionosphere disturbances, in conjunction with geomagnetic storms, have been the subject of close attention from ionosphere specialists for several decades. Ionospheric storms are an extreme form of space weather that has significant negative effects on our society’s increasingly sophisticated ground- and space-based technological systems. We used different types of data sets, like solar wind parameters, interplanetary magnetic field (IMF) Bz, and GPS vertical total electron content (VTEC). We identified 29 IGS network receivers across the European, African, and Asia-Pacific sectors. This study aims to obtain a detailed understanding of the changes in the ionosphere’s total electron content (TEC) in both the northern and southern hemispheres at various geographic longitudinal and latitudinal stations.
Author(s): Aisling O’Hare, Susanna Bekker, Laura Hayes, Ryan Milligan
Queen’s University Belfast; Queen’s University Belfast; European Space Agency (ESA), European Space Research and Technology Centre (ESTEC); Queen’s University Belfast
Abstract: The extreme ultraviolet (EUV) and X-ray radiation emitted during solar flares has been shown to cause considerable increases in the electron density of the Earth’s ionosphere. It has been suggested that flares exhibiting quasi-periodic pulsations (QPPs) in X-ray emission can be linked to subsequent pulsations in the Earth’s ionospheric D-region. Similar pulsations have also been detected in UV/EUV solar flare emission although the extent of their impact on the Earth’s ionosphere is still unclear. Here, we present an investigation searching for quasi-periodic changes in solar flare emission simultaneously observed by various space-based instruments spanning X-ray and EUV wavelengths, including GOES-R/XRS and SDO/EVE. The effect on the Earth’s ionosphere will also be monitored using Total Electron Content (TEC) measurements from GPS receivers. Combining these observations will allow us to probe how sensitive different altitudes of the ionosphere are to rapid changes in the most geoeffective emission lines.
Author(s): Jan Błęcki, Paweł Jujeczko, Roman Wronowski
CBK PAN; CBK PAN; CBK PAN
Abstract: Emissions with extremely high intensity around the electron cyclotron frequency have been registered few times by a satellite Magion 4 a companion of Interball 1 in the polar cusps. These waves which were correlated with strong fluxes of highly energetic electrons have been registered also by CLUSTER satellites. DEMETER satellite registered fluxes of the energetic electrons together with broadband emissions of plasma waves in the ionosphere over the strong thunderstorms. The fluxes of the superthermal electrons are likely the sources of these emissions in both cases. The use of ionospheric satellite gives the chance to perform in situ measurement of plasma parameters during such dynamic processes as geomagnetic storms. For our analysis we used a set of selected data of electric and magnetic field variations in ELF, VLF and HF ranges together with spectra of energetic electrons originated from the French microsatellite DEMETER which was operating on the circular orbit with inclination of about 80o at altitude of 660 km from July 2004 until December 2010. The scientific payload of DEMETER consisted of: ICE – an instrument for electric field variation measurements in ULF/ELF/VLF range from DC (constant field) up to 20 kHz and a HF analyser which measured these variations up to 4 MHz, IDP (ion spectrometer) which measured ion density in a range 5·102 – 5·106/cm3 and ion temperature in a range 1000 – 5000 K, ISL (Langmuir probe) which measured electron density in a range 102 – 5·106/cm3 and electron temperature in a range 500 – 3000 K, IAP (spectrometer for high energy electrons) which measured energetic electrons in a range 30 keV – 10 MeV, IDP which measured ion composition: H+, He+, O+, NO+ , IMSC which measured magnetic field from DC up to 20kHz. The time of DEMETER’s operation was the time of a decreasing Solar activity, but in spite of that we found 5 strong magnetic storms and one superstorm. We will discuss the registration done by DEMETER during these events.
Acknowledgments.
This work is based on observations with the electric field experiment ICE and the magnetic field experiment IMSC embarked on DEMETER. The authors thank J. J. Berthelier the PI of the electric field experiment for the use of the data and M. Parrot PI of magnetic field experiment. We also thank H. D. Betz (LINET) and G. Diendorfer (EUCLID) for the information on the thunderstorm activity. This work has been partially supported by the National Science Centre, Poland (NCN), through grant No. 2021/41/B/ST10/00823.
Author(s): Lilensten Jean, Bosse Léo, Barthélemy Mathieu, Nicolas Gillet, Gaël Cessateur, Herve Lamy, Johnsen Magnar Gullikstad, slava bourgeois
CNRS – IPAG; CALA; UGA – IPAG; CNRS – IsTerre; IASB; IASB; University i Tromsø; Observatório Geofísico e Astronómico Coimbra
Abstract: In 1958, Duncan published a paper showing that the auroral red line was polarized with a Degree of linear polarisation (DoLP) of 30%. This measurement was soon shown to be impossible and the topic was soon forgotten. In 2008, our group came with the same idea based on quantum physics: the red line should be polarized, although at a much smaller rate. Along with the University of Oslo, we built a first instrument (SPP) that would prevent any instrumental artifact. The polarization was discovered in 2009, with a rate varying between 1 and 5%.
In 2015, a new series of polarimeters (the “Cru” series) was conceived and patented by CNRS, France. It analyses each line separately. It allowed to evidence that
All the main auroral lines are actually polarized
This also stands for the nightglow at equatorial latitudes
Modeling and laboratory experiments allowed to retrieve these features and to prove that the polarization is created at the emission. A dedicated radiative transfer code allowed to determine the impact of the low altitude aerosols, making the polarization a good way to characterize them during the night with a passive observation. The same code, compared to measurements in light-polluted areas, allowed to estimate the polarization of the light pollution scattered by the aerosols, making the polarization a way to detect faint light pollution. The last campaigns (2022 – 2024) were devoted to observing a single emission volume from different viewing angles in order to check whether the ionospheric polarization could align with the ionospheric currents.
These discoveries carry some promises. In space weather, they could allow:
To track ionospheric currents in the E region (90 to 110 km)
To track magnetic field variations and the ionospheric currents in the F region (around 220 km).
With numerous industrial applications in several fields, starting with the determination of ionospheric irregularities disrupting HF waves.
Moreover, they could allow:
To characterize the tropospheric aerosols
To detect light pollution
They also challenge our understanding of the quantum states of atomic oxygen.
Finally, the instruments detect all sources of night sky polarization. These sources are used by some night insects for navigation. The technics therefore raises some interest amongst the entomologists.
A complementary instrument called PLIP has been developed at BIRA-IASB with the aim of providing polarization information on a larger FOV than the Cru instruments. It has a lower time resolution but a higher spatial resolution.
In this lecture, we will review these discoveries and show that for a limited cost, this method could provide advances in the next years for space weather monitoring. However, the understanding of the discoveries need to be deepened and more campaigns are necessary, particularly coordinated to EISCAT 3D. Still, there is lots of room for colleagues wishing to open with us this fascinating new window on our space environment.
Author(s): Dorota Przepiórka-Skup, Barbara Matyjasiak, Hanna Rothkaehl
Space Research Centre, Polish Academy of Sciences; Space Research Centre, Polish Academy of Sciences; Space Research Centre, Polish Academy of Sciences
Abstract: The mid-latitude trough (MIT), located in the subauroral regions of Earth’s upper atmosphere, is distinguished by a reduction in ionospheric electron density. This region undergoes profound changes in ionospheric content, influenced by processes originating from the heliosphere and the thermosphere. The MIT represents a significant ionospheric irregularity, reaching its peak development during nighttime. The morphological features, size, and location of the mid-latitude trough (MIT) display variability influenced by many factors, operating across both short-term and long-term timescales. The dynamic features emphasise the complex interaction between solar influences and atmospheric processes within the thermosphere. This positions MIT as a crucial element in the context of space weather.
This study focuses on the MIT variability over long timescales, addressing the dependence on seasonal and solar activity. This study pioneers a numerical and statistical description of MIT morphology, revealing an asymmetrical nature. About 70% of the analysed MIT structures displayed a steeper polar gradient, while only 30% exhibited less pronounced asymmetries or slightly steeper equatorial gradients. Despite the predominance of the asymmetrical morphologies with the steeper polar wall, the specific ratios of the polar wall gradient to the equatorial wall gradient vary with the change of seasons. The hemispheric asymmetry is also evident. The northern trough morphology exhibits greater sensitivity to seasonal variations than the southern trough morphologies. In addition to solar processes, Earth-based factors, such as the configuration and variability of Earth’s magnetic field, should be considered. Earth’s magnetic field, characterised by North-South asymmetry, may play a crucial role in trough formation. However, further analysis is needed to understand better the relationship between Earth’s magnetic field characteristics and MIT.
These findings stem from a thorough analysis utilising DEMETER, SWARM and DMSP observations, encompassing various geomagnetic conditions.
Author(s): Lucilla Alfonsi, Wojciech J. Miloch, Nicolas Bergeot
ALFONSI LUCILLA; University of Oslo, Norway; Royal Observatory of Belgium, Belgium
Abstract: AGATA (Antarctic Geospace and ATmosphere research) is a Programme Planning Group approved by SCAR (Scientific Committee on Antarctic Research) to propose a new Scientific Research Programme (SRP) after more than 10 years from the previous initiative on similar topics. The proposed SRP will aim to gather the scientific communities working on polar regions to answering the outstanding scientific questions within atmospheric and space physics over polar regions:
How are different atmospheric layers coupled in the polar regions?
How does the upper polar atmosphere respond to increased geomagnetic activity, including energy transfer from space?
How does the whole polar atmosphere impact short- and long-term climate variations?
As the central role of the polar regions in understanding the coupling between the magnetosphere and the neutral and the ionized atmosphere (ionosphere), answering these questions will not only have implications on the understanding of processes in the polar atmosphere, but it will also greatly improve our understanding of the global atmospheric dynamics, thus contributing to the development of large-scale whole atmosphere and climate models.
If approved by SCAR, the AGATA SRP will bring together communities which investigate the polar atmosphere and geospace, with a particular focus on Antarctica, but also with a bi-polar perspective. AGATA will be a coordinated, worldwide effort to monitor, investigate and better understand the physics of the polar atmosphere and the impact of the Sun-Earth interactions on the polar regions. AGATA will take advantage of existing and planned instrumentation in Antarctica, but also in the Arctic and satellite-based observations, and it will aim for coordinated research efforts and data exchange. AGATA will also be important for sciences that depend on the removal and mitigation of negative effects of the atmosphere on their observations (such as, e.g., radio astronomy and geodesy). At this stage the AGATA Planning Group is working for submitting the proposal for the new SRP to SCAR and it welcomes new members to contribute to our endeavor. To learn more you can visit the AGATA web pages: www.scar.org/science/agata/home/
Author(s): Gareth Dorrian, Hannah Trigg, Ben Boyde, Alan Wood, Richard Fallows, Maaijke Mevius
University of Birmingham; University of Birmingham; University of Birmingham; University of Birmingham; RAL Space; ASTRON
Abstract: Quasi-periodic scintillations (QPS) are recurrent features in radio scintillation observations caused by plasma structures in the Earth’s ionosphere. Generally they are categorised into two forms, symmetric and asymmetric. Symmetric QPS are characterised by a series of signal intensity fringes either side of a distinct v-shaped signal fade in LOFAR dynamic spectra. In previous literature, such features have only been observed using single channel scintillation observations. Here we present LOFAR broadband ionospheric scintillation observations of exceptionally well defined symmetric quasi-periodic scintillations. Two case studies are shown, one from 15th. December 2016, and one from 30th. January 2018, in which well-defined main signal fades and secondary diffraction fringing are observed. In particular, the broadband observing capabilities of LOFAR permit us to see considerable frequency dependent behaviour in the QPS which, to our knowledge, is a new result. Very clear examples of scintillation arcs are extracted from delay-Doppler spectral analysis of these two events, which permit the estimation of propagation velocities for the plasma structures causing the QPS ranging from 50-200 ms-1. Spacing between each individual plasma structure ranges between 5-20 km. Each of the two events is accurately reproduced using a Gaussian perturbation thin phase screen model using small variations in total electron content (TEC) amplitudes of order 1 mTEC, demonstrating the sensitivity of LOFAR to very small fluctuations in ionospheric plasma density. To our knowledge these results are among the most detailed observations and modelling of this particular phenomena in the literature.
Author(s): Simone Mestici, Fabio Giannattasio, Paola De Michelis, Alessio Pignalberi, Roberta Tozzi, Francesco Berrilli, Giuseppe Consolini
Università di Roma La Sapienza; Istituto Nazionale di Geofisica e Vulcanologia; Istituto Nazionale di Geofisica e Vulcanologia; Istituto Nazionale di Geofisica e Vulcanologia; Istituto Nazionale di Geofisica e Vulcanologia; Università di Roma Tor Vergata; Isituto Nazionale di Astrofisica – IAPS
Abstract: The dynamic properties of ionospheric plasma are closely related to solar activity and geomagnetic conditions. The coupling between solar wind and the Earth’s magnetosphere-ionosphere system is particularly evident in the high-latitude ionosphere, where solar wind and the orientation of the interplanetary magnetic field have a great impact on plasma circulation and partially contribute to the formation of ionospheric irregularities. At the same time, seasonal variations, i.e., different sunlit conditions, also have a strong influence on the ionosphere’s dynamics. Over the past years, significant efforts have been made to develop and improve ionospheric models. Nevertheless, a comprehensive understanding of the processes that regulate plasma dynamics in different conditions has yet to mature, and thus further studies are required.
In this scenario, we use spherical harmonic decomposition to study the dependence of electron density in the topside ionosphere and at high latitudes on magnetic local time, solar activity, local season, and interplanetary magnetic field orientation. Our dataset consists of almost ten years of measurements, from 1 June 2014 to 31 December 2023, collected by the Swarm constellation with a sampling rate of 1 Hz. We provide discrete maps of electron density for both hemispheres under different activity conditions and seasons and use interpolation to model density patterns at intermediate conditions. We then discuss the results obtained in light of the literature and previous models.
Author(s): Jan Rusz, Jaroslav Chum, Jiří Baše
Institute of Atmospheric Physics CAS; Institute of Atmospheric Physics CAS; Institute of Atmospheric Physics CAS
Abstract: The statistical analysis is based on measurements by multi-point, multi-frequency continuous Doppler sounding system (CDS) combined with measurements by a nearby ionosonde. Both systems are situated in the western part of the Czech Republic. A configuration of the system allows to determine not only the vertical oscillation plasma velocity proportional to Doppler shift, but also the velocity and direction of GWs propagation at different heights.
The GWs carry energy from the lower to higher altitudes, dissipating and depositing their momentum and energy along the way. The amplitude of GWs increases with height due to the decrease in the density of the atmosphere, but at the same time the attenuation of the waves also increases due to the dissipation of energy through internal fluid friction.
The energy of medium-scale GWs with periods ranging from 5 to 60 minutes, propagating in the ionosphere, is measured and statistically analyzed to explore their daily and annual variations. This analysis also examines the relationship between wave energy and the altitude of observation. The results from the solar maximum and solar minimum periods are compared.
Author(s): Jeff Klenzing, Alexa Halford, Jonathon Smith
NASA GSFC; NASA GSFC; Catholic University of America / NADA GSFC
Abstract: The Responsive Environmental Assessment Commercially Hosted (REACH) project is a set of hosted, hosted payloads from the Aerospace Corporation. These payloads are on 32 Iridium-Next satellites which were deployed over the course of 8 launches from Feb 2017 through March 2019. This put the constellation into 6 different orbital planes allowing for amazing magnetic local time coverage. Each of the 32 payloads has two dosimeters which are able to capture the broad dynamics of important particle populations for space weather impacts. The historic REACH data has recently been archived at the NASA Space Physics Data Facility. This paper presents an overview of the dataset and the utility in Space Weather applications.
Author(s): M Mainul Hoque, N Jakowski, J A Cahuasquí, G Nykiel
German Aerospace Center DLR; German Aerospace Center DLR; German Aerospace Center DLR; Gdansk University of Technology, Gdansk, Poland
Abstract: Ionospheric ionization may cause serious propagation errors in modern radio systems such as Global Navigation Satellite Systems (GNSS) and space-based remote sensing radars. In particular reliable information on the perturbation degree of the ionosphere is required in safety of life applications (e.g. Space or Ground Based Augmentation Systems to guide aircraft landing) or precise navigation and positioning in many GNSS applications with permanently growing challenges concerning accuracy, continuity, availability and integrity. Space weather services are able to help customers of these systems by providing compact and easy to use information on the perturbation degree of the ionosphere like index numbers in a standardized scale. To estimate spatial gradients and rapid temporal variations of ionospheric total electron content TEC, DLR has developed two approaches recently (Jakowski and Hoque 2019). The Gradient Ionosphere index (GIX) and the Sudden Ionospheric Disturbance indeX (SIDX) are able to estimate the perturbation degree of the ionosphere instantaneously without considering previous measurements. In this study, we would present the relationship between the GIX and SIDX indices, and GNSS positioning results. We would compare the impact of the St. Patrick’s Day storm (17-18 March 2015) and the recent storm 10-14 May 2024 on the computed indices as well as on positioning results. Early investigation shows that although the May storm is much stronger the impact on positioning is smaller over Europe. This is obviously due to the different storm onset times. We can verify this hypothesis by studying the behavior at other longitude sectors with different local times. So, the May storm indicates strong effects at the American sector at daytime, when farmers’ tractor GPS systems failed during peak planting season. It is assumed that the local time of storm onset plays an important role, not only the strength of the storm.
Reference:
Jakowski N, Hoque MM (2019) Estimation of spatial gradients and temporal variations of the total electron content using ground‐based GNSS measurements. Space Weather, 17. https://doi.org/10.1029/2018SW002119
Author(s): Sk Samin Kader, Dr. Tarun Kumar Pant
Space Physics Laboratory, Vikram Sarabhai Space Centre, ISRO, Govt. of India, Dept. of space, Thiruvananthapuram, India.; Space Physics Laboratory, Vikram Sarabhai Space Centre, ISRO, Govt. of India, Dept. of space, Thiruvananthapuram, India.
Abstract: The response of mid latitude to equatorial Ionosphere-Thermosphere system during April 2023 geomagnetic storm is analyzed using multi-instrument, ground and satellite, observations. This geomagnetic storm exhibited several intriguing characteristics, revealing additional complexities in ionospheric and thermospheric responses. The shock front, associated with the Interplanetary Coronal Mass Ejection (ICME) which caused this storm, was detected at the L1 point at around 17:00 UT on April 23, 2023, and it induced a geomagnetic storm at Earth’s magnetosphere at around 17:45 UT. The ionospheric plasma density obtained from the SWARM satellite data indicated an enhanced Equatorial Ionization Anomaly (EIA) during the storm’s main phase, attributable to the Prompt Penetration Electric Field (PPEF). Significant fluctuations in top-side Total Electron Content (TEC) and ion density were also observed during both the main and recovery phases of the storm. The hourly vertical TEC variations, derived from the Global Ionospheric Map (GIM), showed substantial enhancements and depletions across different longitudinal regions during various storm phases.The Special Sensor Ultraviolet Spectrographic Imager (SSUSI) detected an equatorward expansion of the auroral oval. Additionally, equatorward thermospheric winds, driven by Joule heating over polar regions, had a considerable impact on mid to low latitudes regions, as evidenced by changes in the [O/N2] ratio. Furthermore, north–south asymmetry is observed in terms of O/N2 ratio changes during the recovery phase of the geomagnetic storm. The significant variation in the different longitude sector in terms of TEC fluctuation were observed during recovery/main phases and were mainly attributed to the effects of PPEF, Disturbance Dynamo Electric Field (DDEF) and the thermospheric neutral winds. This geomagnetic storm shows some unique characteristic in terms of its effect along the different longitude regions with local time dependency. In this regard, study of this type of events are important for improvement of ionospheric modeling. Detailed results will be presented during the meeting.
Author(s): Pelin Iochem, Claudia Borries, Samira Tasnim, Jürgen Kusche, Anita Aikio, Lei Cai, Ilkka Virtanen, Nada Ellahouny
Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany; Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany; Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Neustrelitz, Germany; Institute of Geodesy and Geoinformation, Rheinische Friedrich-Wilhelms-University of Bonn, Bonn, Germany; University of Oulu, Space Physics and Astronomy Research Unit, Oulu, Finland; Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland; Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland; Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
Abstract: Solar wind-magnetosphere interaction causes persistent energy deposition at the high latitudes Earth system continuously modifying the ionospheric and thermospheric structures. The modifications are reflected in variations of the electric field, thermosphere heating, plasma transport, thermospheric composition, circulation and other effects. These significant variations do not only affect the high latitude region but also have an impact on a global scale. This work aims to explain the mechanisms that could be responsible for the response of the ionosphere- thermosphere system to the solar wind and interplanetary magnetic field variations.
Since the variations in the ionosphere are easily monitored by the Total Electron Content (TEC), we use this parameter with a data coverage of more than twenty years and with 2.5°x5° degree spatial and 2-hour temporal resolution. The ionosphere conditions are studied at Tromsø, Norway (69.58°N, 19.23°E), where the most continuous dataset of IGS TEC can be combined with EISCAT UHF incoherent scatter radar observations on electron density altitude profiles. For the solar wind data, we use 2-hour resampled Advanced Composition Explorer (ACE) and derive the geoeffective interplanetary electric field, which is used for the estimations of the solar wind energy input into the magnetosphere. In our analyses, we apply a cross-correlation method with a moving 90-day window that generates a dataset of the correlation values corresponding to the variation of TEC with merging electric field. The method also delivers the time lag between ionosphere and solar wind variations.
We observe moderate correlations (±0.8) between TEC and merging electric field, which shows strong solar cycle, seasonal and local time dependence. Our three main results are: 1) a positive correlation during winter nighttime; 2) a noontime anomaly with a positive correlation; and 3) a negative correlation during summer. We show that the ionospheric response is with a delay of ≈4 hours during winter nighttime and a longer delay of ≈18 hours during summer conditions. Particle precipitation, Joule heating, and plasma convection are the expected driving mechanisms behind the observed ionospheric response. EISCAT UHF radar CP1 and CP2 measurements at the Tromsø location are analyzed for three corresponding events to identify the contribution of the different mechanisms to the response.
Author(s): ANKIT GUPTA
CSIR National physical Laboratory New Delhi, Academy of scientific and innovative research Ghaziabad
Abstract: This study investigates the impact of solar eclipses that occurred during the year 2014 to 2023, affecting Indian region ionosphere, using F2 layer critical parameters (foF2, hmF2) obtained using Digisonde from a low-mid latitude Indian station, Delhi (28.6°N, 77.2°E, 19.2°N). Four solar eclipse events that occurred during this period are examined, taking into account their varying degrees of obscuration, duration, and timing. The availability of this unique dataset provides a valuable opportunity to investigate the intricate relationship between the ionosphere and different solar disturbances. The findings indicate that the F2 layer of the ionosphere is responsive to the extent of obscuration, duration, and onset time of the eclipse. Additionally, the study examines the correlation between the E layer and Vertical Total Electron Content (VTEC) during solar eclipses, revealing a significant level of dependence. Furthermore, it is observed that the recovery time of the ionospheric layers is approximately twice as long as the time required for maximal variations within these layers. The study also indicates the presence of gravity waves during these eclipses.
Author(s): Veronika Barta, Tamás Bozóki, Dávid Péter Süle, Daniel Kouba, Jens Mielich, Tobias G.W. Verhulst, Tero Raita, Attila Buzás
HUN-REN Institute of Earth Physics and Space Science, Sopron, Hungary; HUN-REN Institute of Earth Physics and Space Science, Sopron, Hungary; HUN-REN Institute of Earth Physics and Space Science, Sopron, Hungary; Institute of Atmospheric Physics, Czech Academy of Sciences, Prague, Czech Republic; Leibniz-Institute of Atmospheric Physics, Rostock, Germany; Royal Meteorological Institute (RMI), Brussels, Belgium; Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland; HUN-REN-ELTE Space Research Group, Budapest, Hungary
Abstract: The sudden increase of Solar X-ray and EUV emission during solar flares causes increased ionization and absorption of electromagnetic (EM) waves in the sunlit hemisphere of the Earth’s ionosphere. Solar flares are also often accompanied by energetic particles which can lead to additional ionization and absorption especially at the higher latitudes (> 60 °). One way to determine the ionospheric absorption changes is to use the minimum reflection frequency, fmin, derived from ionograms, which is the rough measure of the “non-deviative” radio wave absorption. Therefore, it can be used as an index during high absorption changes caused by e.g. solar flares. It is also possible to determine the ionospheric absorption changes with the signal-to-noise ratio of radio waves obtained from ionograms (SNR method) during flares compared to values obtained from reference. A novel method has been developed by Buzás et al. [1] based on the amplitude data of the EM waves measured by Digisondes to calculate and investigate the relative absorption changes (compared to quiet period) occurring during solar flares. The effect of 13 (>C4.8) solar flares that occurred between 06:00 and 16:30 (UT, daytime LT = UT+2 h) from 04 to 10 September 2017 have been studied using this so-called “amplitude method”. Total and partial radio fade-outs, furthermore, +20%–1400% amplitude changes (measured at 2.5 and 4 MHz) were experienced at three European Digisonde stations during and after the investigated flares.
The most common instruments to determine the ionospheric absorption are the so-called riometers (Relative Ionospheric Opacity meter) which analyze the cosmic radio noise measured at certain frequencies (usually ~ 30 MHz). However, these instruments are generally installed at high geographic latitudes (>60°). The results of the amplitude method and the absorption changes measured by the Finnish Riometer Chain have been compared with the values determined by the NOAA D-RAP model during the same 13 solar flare events. The X-class flares caused 1.5–2.5 dB attenuation at 30–32.5 MHz based on riometer data, while the absorption changes were between 10 and 15 dB in the 2.5–4.5 MHz frequency range (thus 10 times higher) according to the amplitude data measured by the Digisondes. According to the comparison of the values predicted by D-RAP model with the observed Digisonde (amplitude) and riometer data, the model underestimates the ionospheric absorption changes caused by solar flares and overestimates the impact of the energetic particles at higher latitudes. Another promising way to determine the ionospheric absorption with Digisondes is the “riometer operational mode”, which the Digisonde is able to listen to the radio universe above foF2 up to the maximum 30 MHz limit.[1] Buzás, A., Kouba, D., Mielich, J., Burešová, D., Mošna, Z., Koucká Knížová, P., & Barta, V. (2023). Investigating the effect of large solar flares on the ionosphere based on novel Digisonde data comparing three different methods. Frontiers in Astronomy and Space Sciences, 10.
Author(s): Irfan Azeem, Dimitrios Vassiliadis, Nicholas Zaremba
NOAA/Office of Space Weather Observations; NOAA/Office of Space Weather Observations; NOAA /Office of Space Weather Observations
Abstract: The National Oceanic and Atmospheric Administration (NOAA) plays a critical role in monitoring and forecasting space weather phenomena. NOAA’s National Environmental Satellite, Data, and Information Service (NESDIS) is responsible for the continuity of critical space weather observations supporting operational forecasts and warnings. One key area of interest for NOAA/NESDIS is the measurement of auroral intensity from space, as it indicates particle energy input into the upper atmosphere. Continuous remote sensing of Earth’s high-latitude polar regions offers the potential for new, unique, and valuable space weather services. Currently, NOAA relies on the OVATION (Oval Variation, Assessment, Tracking, Intensity, and On-line Nowcasting) model to provide short-term forecasts of the location and intensity of the aurora based on solar wind inputs. Supplementing this model with direct measurements of the auroral oval boundary and intensity would enhance our understanding by characterizing temporal and spatial variations in the auroral zone ionosphere. Additionally, imaging of the aural oval can reveal the polar cap location, where solar energetic particles induce ionization of the D-layer of the ionosphere, impacting HF communications. Data on conductivity and energy deposition in this region, derived from auroral imaging, can be assimilated into geospace models, improving the accuracy of geomagnetic disturbance predictions. These enhanced models are crucial for geoelectric models that support the power grid and other critical infrastructure. This paper details NOAA’s operational needs for auroral observations from space, underscoring the necessity for improved spatial and temporal resolution, real-time data acquisition, and advanced predictive capabilities to meet the demands of space weather forecasting and mitigation.
Author(s): Daria Kotova, Luca Spogli, Yaqi Jin, Rayan Imam, Wojciech Miloch
Department of Physics, University of Oslo; Istituto Nazionale di Geofisica e Vulcanologia; Department of Physics, University of Oslo; Istituto Nazionale di Geofisica e Vulcanologia; Department of Physics, University of Oslo
Abstract: This study presents the first results showing the impact of Strong Thermal Emission Velocity Enhancement (STEVE) on the GNSS signals. STEVE is a narrow ribbon of light that appears in the night sky, often alongside the aurora borealis. Unlike the typical green and pink hues of the auroras, STEVE displays a distinct mauve or purple colour, as a visible manifestation of energy transfer in the upper atmosphere. The high velocity and temperature in the ionosphere effectively heat the thermosphere and supply nitrogen (N₂) at the altitudes where STEVE emissions occur (approximately 130–270 km). This energy input can lead to growing instability leading to irregularities in plasma that can affect the propagation of transionospheric radio signals. To conduct this study, we use dataset from the all-sky camera and 50 Hz data from two GNSS Ionospheric Scintillation and TEC Monitor receivers in Dronning Maud Land, Antarctica. The All-Sky Imager (ASI) at the Norwegian Research Station Troll is working at the wavelength of three filters (557.7 nm, 630.0 nm) corresponding atomic auroral and airglow emission lines and N2+ emission (427.8 nm) in the Earth’s atmosphere. The NovAtel GPStation-6 receiver is also installed in the Troll station, co-located with ASI. We also use ground-based data acquired by the Septentrio PolaRx5S receiver from South African Research Station SANAE IV located 186 km from Troll. Both stations are located on the equatorward edge of the quiet auroral oval. Thus, observatories are in the optimal location to study the ionospheric response to geomagnetic disturbances and the effect of subauroral activities on transionospheric signal and accuracy of positioning. An event was selected when a narrow STEVE arch, visible in the all-sky camera image data, appeared over the stations. The selected conditions corresponded to the subauroal activity of quiet geomagnetic conditions. Of the three possible filters of ASI, we use the red filter images (630.0 nm) because STEVE is more represented in it. We show that at the time when the ionospheric pierce point (a projection of GNSS satellite data to the height of the electron density maximum in the ionosphere) crosses STEVE the signal experiences scintillation in phase and the amplitude above the noise level of the receiver. Understanding STEVE’s origin and behaviour can provide insights into the complex interactions in the subauroral regions between the Earth’s magnetosphere, ionosphere, and thermosphere. Monitoring STEVE events can enhance our understanding of ionospheric dynamics, which play a crucial role in radio wave propagation, satellite communication, and navigation systems.
DK, YJ, WM acknowledge funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC Consolidator Grant agreement No. 866357, POLAR-4DSpace). The station in SANAE IV was deployed in the framework of the DemoGRAPE project funded by PNRA 564 (Progetto di Ricerca 2013/C3.01) and it is run under the Memorandum of Understanding between INGV and SANSA (Delibera CdA INGV 297/2016). LS express his gratitude Dr. Emanuele Pica, Carlo Marcocci, and Lucilla Alfonsi of INGV for the help and support with raw data from the SANAE IV receiver.
Author(s): Philippe Yaya, Roiya Souissi, Ali Naouri, Marie Cherrier
CLS; CLS; CLS; CLS
Abstract: CLS – a subsidiary of the French space agency – is part of the ACFJ consortium (Australia, Canada, France, Japan) and is responsible for providing near real-time maps of ionospheric scintillation for an operational Space Weather service dedicated to civil aviation. In this work, we describe the various steps to generate the maps and discuss their limitation. Taking advantage of almost 5 years of operation, which correspond to the increasing phase of solar cycle 25, the main characteristics of the GNSS-based scintillation observations at low latitudes are outlined. Based on these observations, an empirical model of equatorial scintillations targeted on specific locations was built. Finaly, a forecasting model using machine learning techniques is described in terms of parametrization and accuracy at various horizons up to 24h.
Author(s): Rebecca Ghidoni, Luca Spogli, Maaijke Mevius, Claudio Cesaroni, Lucilla Alfonsi, Katarzyna Beser, Marco Guerra, Tiziano Maestri
Università di Bologna, Italy; Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy; Netherlands Institute for Radio Astronomy (ASTRON), Dwingeloo, The Netherlands; Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy; Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy; Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ, USA; Università “La Sapienza”, Rome, Italy; Università di Bologna, Italy
Abstract: This study focuses on the identification and characterization of ionospheric irregularities duringa minor geomagnetic storm that took place between January 14 and 15, 2022, that allowed us tosimultaneously use the LOw Frequency ARray (LOFAR) telescope and Global Navigation SatelliteSystem (GNSS) receivers over Europe. Combining LOFAR and GNSS offer unique advantages in terms of spatial and temporal resolution, giving us slightly different perspectives on the same ionosphere.A key distinction between these instruments is the frequencies at which they operate: the LOFARLow Band Antennas (LBA) functions at few tens of MHz, while GNSS operates at a few GHz. Thisdifference allows them to detect different spatial scales of ionospheric perturbations, providing amore comprehensive view of the disturbances that occurred during the storm.The differences in the capability of these instruments were especially noticeable consideringthe distribution of the LOFAR core stations in the Netherlands, few hundreds of meters apart fromeach other. We were able to measure the velocity of the ionospheric perturbations that affectedthe signal measured by those antennas with significantly higher precision compared to the dataderived from the variation in Total Electron Content (dTEC) observed by the GNSS satellites.LOFAR’s high-temporal resolution allowed us to focus on finer details of the ionospheric distur-bances, capturing small-scale fluctuations that might not be as apparent from the GNSS data.GNSS, on the other hand, provided a broader overview of the ionosphere. Rate of TEC index(ROTI) measurements from GNSS satellites offered a comprehensive picture of the irregularitiesmap across the ionosphere. Although this method has limitations in precision and spatial resolu-tion, the widespread availability and extensive coverage of GNSS data made it invaluable for ourstudy. It allowed us to track the larger-scale movements and overall behavior of the ionosphericdisturbances throughout the storm.The ability to integrate data from both LOFAR and GNSS thus enabled a multi-scale analysis,combining the micro-level precision of LOFAR with the macro-level coverage of GNSS.
Author(s): Bushra Gul
University Of Karachi
Abstract: The proof of first principle established in preliminary work has been validated over a wider spatio-temporal range in which the relationship between ionosonde measured foEs has been studied with disturbed zonal wind (dzw) obtained from Horizontal Wind Model (HWM14) over mid latitudinal stations from both hemispheres. The data spans over two solar cycles (1996-2019) from Rome (geog coord: 41.9◦N, 12.49◦E), Kokubunji (37.7◦N,139.46◦E), Yamagawa (35.4◦N, 133.6◦E), Grahamstown (33.15◦S, 26.52◦E), Okinawa (26.3◦N , 127.8◦E). The relation between foEs and dzw was investigated by estimating correlation coefficients (cc) considering major stormcondition (Ap=80) at 100 km altitude. High cc values were found (> 0.8) at the north hemispheric stations. The highest cc was observed at Kokubunji (0.97, year:2000). Conversely cc values observed at Grahamstown (south-ern hemisphere) were not promising. This may be due to the lack of data availability in HWM14. Temporal coverage shows no significant influence of solar and geomagnetic activity level variations on frequency and stochastic parameters of mid-latitude sporadic-E layer. On the basis of higher cc values, it may be said that the latitudinal fluctuations in Es- layer properties aresignificantly correlated with zonal wind shear.
Author(s): Ebenezer Agyei-Yeboah, Paulo Roberto Fagundes, Alexandre Tardelli, Valdir Gil Pillat, Francisco Vieira, Mateus de Oliveira Arcanjo
Universidade do Vale do Paraiba, Brazil; Universidade do Vale do Paraiba, Brazil; Universidade do Vale do Paraiba, Brazil; Universidade do Vale do Paraiba, Brazil; Observatório de Física Espacial, Instituto Federal de Tocantins, Brazil; Universidade do Vale do Paraiba, Brazil
Abstract: The influence of sudden stratospheric warming (SSW) on the ionosphere and ionospheric irregularities has been studied extensively over the years. However, majority of these investigations have been conducted using warming events originating from the northern hemisphere. Only a few studies have been done on ionospheric variations due to the Antarctic SSW events and to the best of our knowledge, there have not been any studies on southern hemisphere SSW and the occurrence of ionospheric irregularities. In this study, the occurrence of ionospheric irregularities during the 2019 minor Southern hemisphere (SH)/Antarctic SSW is investigated. The event occurs in a relatively calm solar and geomagnetic activity period which makes it possible to identify the effects of SSW on the occurrence of irregularities. Three ionosondes located in different latitudinal regions in Brazil as well as a network of ground-based GPS receiver stations located in both Brazil and Africa were used for this undertaking. Complimentary data from the same ionosonde stations using the same months from 2017 and 2018 were also used. On average more Spread-F was observed in 2019 than in 2017 or 2018 at all stations. ROT observations showed more occurrence in the Brazil sectors followed by West Africa and thenEast Africa. It was observed that the occurrence frequency decreased between 8% and 46 % from the pre-SSW phase to ascending/peak phases and from 2018 to 2019 for the peak phase.
Author(s): Ebenezer Agyei-Yeboah, Paulo Roberto Fagundes, Alexandre Tardelli, Universidade do Vale do Paraiba, Brazil, Alessio Pignalberi, Venkatesh Kavutarapu, Michael Pezzopane, Francisco Vieira
Universidade do Vale do Paraiba, Brazil; Universidade do Vale do Paraiba, Brazil; Universidade do Vale do Paraiba, Brazil; Universidade do Vale do Paraiba, Brazil; Istituto Nazionale di Geofisica e Vulcanologia, Italy; National Atmospheric Research Laboratory (NARL); Istituto Nazionale di Geofisica e Vulcanologia, Italy; Observatório de Física Espacial, Instituto Federal de Tocantins, Brazil
Abstract: This investigation uses simultaneous observations from all-sky imager system and an ionosonde collocated at Araguatins (5.65° S, 48.07° W and dip-latitude of 4.17° S), a near-equatorial region in Brazil. These simultaneous observations were used to investigate the occurrence of plasma bubbles and blobs in the field of the imaging system and their association with atypical range Spread-F signature in ionograms. Also, in-situ observation of plasma density from Swarm satellites were used to support the ground-based observations. Using a few cases, a methodology will be established to identify in the plasma blobs (atypical ESF) in the ionograms when there is the simultaneous observation of plasma bubbles and blobs in the field of view of the ionosonde. For this purpose, simultaneous sequence of OI 630.0 nm nightglow images and ionograms are presented for different case studies; 1. when there is the absence of a plasma bubble or blob, 2. when there is only the occurrence of plasma bubbles and 3. when there is the occurrence of plasma bubbles and blobs, in order to compare traces in the ionogram in all these case studies. With these we can cover all kinds of signatures in the ionograms corresponding to no irregularities, plasma bubbles only and plasma bubbles-blobs. These OI 630.0 nm nightglows and ionograms recorded simultaneously make it possible to establish a novel methodology to recognize in ionograms cases when there is the occurrence of Spread-F signature associated with bubble-blob in the FOV of the ionosonde.
Author(s): Ola Abu Elezz, Ahmed Yassen, Pierre Cilliers
Space Weather Monitoring Center (SWMC), Faculty of Science, Helwan University, Cairo, Egypt.; Institute of Basic and Applied Sciences, Egypt-Japan University of Science and Technology, Alexandria, Egypt.; South African National Space Agency (SANSA), Hermanus, South Africa.
Abstract: In this study, The ionospheric electron density profiles predicted by the NeQuick2 model are evaluated using data collected during the geomagnetic storm of 28 May 2017 (Dst = -125 nT, Kp(max)=7). The predicted electron density profiles by the NeQuick2 model were compared with the measurements from the Ionosonde stations in South Africa, such as Hermanus (-34.42°N, 19.22°E), Grahamstown (-33.30°N, 26.50°E), and Madimbo (-22.39°N, 30.88°E), and with the IRI2016 model results. We have found the NeQuick2 model overestimates both the peak electron density by an average of 50 electrons/m3 and the height of the peak density by an average of 50 km, as determined from the Ionosonde measurements. The electron density profiles predicted by the IRI 2016 model are closer to the Ionosonde measurements than the NeQuick2 model. Both the NeQuick2 and IRI 2016 models and the Ionosonde measurements indicate that the electron density on the storm day was less than the values during the geomagnetically quiet day on 3 May 2017) thus confirming a negative storm on 28 May 2017.
Author(s): Nai-Yu Wang, Eric Sutton, Tzu-Wei Fang, Irfan Azeem
NOAA NESDIS Office of Space Weather Observations; University of Colorado; Space Weather Prediction Center; NOAA NESDIS Office of Space Weather Observations
Abstract: Thermosphere neutral density (TND) is important for studying coupling processes within the Earth’s Ionosphere-Thermosphere-Magnetosphere (ITM) and for orbit determination of satellites in the Low Earth Orbit (LEO). Predicting and estimating TND is challenging because of the variability in the solar radiation inputs at different wavelengths and energy dissipation by auroral electric fields and currents in the polar ionospheres, space weather events such as geomagnetic storms, the interactions between atmospheric neutral molecules/atoms and charged particles, can results in significant changes in the density of neutral atoms and molecules. Since satellite drag is directly related to thermosphere neutral density, there is a substantial interest for operational modeling and prediction of the thermosphere. Large constellations of commercial SmallSats equipped with Global Navigation Satellite System (GNSS) devices bring the opportunity and make them valuable sources of Precision Orbit Determination (POD) information. Additional ability to monitor satellite attitudes enables the construction of more accurate force model. These information can be combined to derive the TND and then use the derived TND to initialize and constrain physics based ITM models. To this end, NOAA NESDIS Office of Space Weather Observations (SWO) and Space Weather Prediction Center (SWPC) are conducting a study to explore the potential of using orbit ephemeris to derive on-orbit neutral density from a large number of SpaceX Starlink satellites and utilize these measurements in a data-assimilative system with the Whole Atmosphere Model-Ionosphere Plasmasphere Electrodynamics (WAM-IPE), and evaluate the performance improvement in the specification and forecasts of TND. We will discuss the status of the retrieval of the thermosphere neutral density data from the Starlink constellation, the validation of derived TND with the high accuracy satellite drag model (HASDM), and the progress towards the implementation of a data assimilative system with the WAM-IPE model.
Author(s): Jaroslav Urbar, Jaroslav Chum, Lubos Rejfek, Vladimir Truhlik, Jan Rusz
Institute of Atmospheric Physics ASCR; Institute of Atmospheric Physics ASCR; Institute of Atmospheric Physics ASCR; Institute of Atmospheric Physics ASCR; Institute of Atmospheric Physics ASCR
Abstract: We present statistical relations between GNSS positioning deviations obtained using state-of-the-art Septentrio receivers as well as low-cost receivers and wide range of ionospheric disturbance parameters available for Europe, including indicators of Travelling Ionospheric Disturbances developed within the TechTIDE project.
The main outcome is that the ionospheric F-layer Doppler frequency-shift (dF), measured by HF Continuous Doppler Sounding Systems (CDSS) strongly correlates having positive dF during positive altitude deviations (and vice-versa). We are currently extending the CDSS network, operational in Czechia, Slovakia, Germany and Belgium, as well as in Argentina, South Africa and Taiwan, to other locations of interest.
The CDSS can also identify the 3-D parameters of the Medium Scale Travelling Ionospheric Disturbances and related infrasound.
Author(s): Dmytro Sydorenko, Robert Rankin
University of Alberta; University of Alberta
Abstract: A comprehensive 3D model of the high-latitude ionosphere has been developed. The model covers magnetic latitudes above 40 degrees and altitudes from 90km to about 1200 km. It calculates the evolution of the ionospheric plasma using fluid equations and accounts for chemical reactions, ionization by solar EUV and photoelectrons, heating and cooling processes, the global convection electric field, neutral wind, tilt of the geomagnetic field, date, and the time of the day. The model has been used to simulate the formation of sporadic E-layers produced by the compression of clouds of metallic ions (Mg+) and outputs data files containing the electron density as a function of altitude, latitude, and longitude at consecutive times. These outputs can be used as input by a ray-tracing code to understand how OTHR radar is affected by intervals of Sporadic E. The algorithm is written in Fortran and parallelized with MPI and is intended for use as an operational model for space weather characterization of the high-latitude ionosphere.
Author(s): Giorgio Arlan da Silva Picanço, Paulo Roberto Fagundes, Luciano Pedro Oscar Mendoza, Clezio Marcos Denardini, Amalia Margarita Meza, Maria Paula Natali, Valdir Gil Pillat, Esmeralda Romero Hernández, Rogelio Aguirre Gutierrez, Irapuan Rodrigues
Research and Development Institute, University of Vale of Paraíba (IP&D/UNIVAP), São José dos Campos, Brazil; Research and Development Institute, University of Vale of Paraíba (IP&D/UNIVAP), São José dos Campos, Brazil; Faculty of Astronomical and Geophysical Sciences, National University of La Plata (FCAG/UNLP), La Plata, Argentina; National Institute for Space Research (INPE), São José dos Campos, Brazil; Faculty of Astronomical and Geophysical Sciences, National University of La Plata (FCAG/UNLP), La Plata, Argentina; Faculty of Astronomical and Geophysical Sciences, National University of La Plata (FCAG/UNLP), La Plata, Argentina; Research and Development Institute, University of Vale of Paraíba (IP&D/UNIVAP), São José dos Campos, Brazil; Faculty of Physical-Mathematical Sciences, Autonomous University of Nuevo León (FCFM/UANL), Monterrey, Mexico; Faculty of Physical-Mathematical Sciences, Autonomous University of Nuevo León (FCFM/UANL), Monterrey, Mexico; Research and Development Institute, University of Vale of Paraíba (IP&D/UNIVAP), São José dos Campos, Brazil
Abstract: Global Navigation Satellite Systems (GNSS) play an important role as a primary data source for deriving several ionospheric parameters, including Total Electron Content (TEC), which quantifies plasma density in terms of free electrons in the satellite-receiver path. During space weather events, GNSS data contributes significantly to understanding ionospheric variability through the analysis of TEC-derived indices such as the Disturbance Ionosphere indeX (DIX) and the Rate of Change of TEC Index (ROTI). However, calculating these indices is not always feasible due to challenges in the reproducibility of methodologies for TEC calculation and the availability of software tools. Often, these methodologies are complex and not readily accessible or standardized, making it difficult for researchers to consistently derive and utilize TEC-derived indices. Thus, in this paper, we introduce an Open-Access System for Ionospheric Studies (OASIS) for preprocessing GNSS data and generating parameters such as TEC, DIX, and ROTI as output. OASIS is capable of detecting and correcting large, medium, and small-amplitude cycle slips, as well as phase/pseudorange outliers. The preprocessed data is leveled and utilized to derive TEC, DIX, and ROTI from 15- and 30-second RINEX files. Furthermore, the software utilizes data from multi-frequency combinations of GPS, GLONASS, Galileo, and BeiDou receivers. The entire library is developed using open-source tools, specifically Python and Bash. To evaluate OASIS outputs, we focused our analysis on a geomagnetic storm period, specifically examining the occurrence of equatorial plasma bubbles with high spatiotemporal resolution alongside ionospheric disturbances related to disturbed electric field penetration. The results show that the software can handle multi-frequency and multi-constellation GNSS data and highlight its potential as a user-friendly, freely accessible tool for studying local, regional, and global ionospheric responses to space weather events. Finally, this study emphasizes the significance of GNSS as a reliable source for monitoring and analyzing ionospheric conditions during space weather disturbances.
Author(s): Gilda González
UC Berkeley
Abstract: Plasma bubbles have the potential to disrupt radio communications and satellite-based
navigation. The influence of geomagnetic storms on these irregularities remains not
fully understood, particularly in how they may affect their generation or suppression.
Enhanced predictive capabilities require comprehensive studies of the ionosphere’s
behavior. The purpose of this research is to analyze the generation or inhibition of
ionospheric irregularities in the F region at low latitudes during geomagnetic storms. To
conduct the analysis, we use ICON IVM ion density and vertical drift, ICON FUV data
and GOLD OI 135.6 nm radiance maps. Additionally, we consider ICON MIGHTI
wind data (red line emission) to study the role of the neutral wind. Our results suggest
that the storm-time electric fields play an important role in the development of
irregularities. The potential drivers of the plasma bubbles variability during disturbed
geomagnetic conditions will be examined using wind profiles provided by ICON
MIGHTI.
Author(s): Tinlé PAHIMA, Doua Allain GNABAHOU, Frédéric OUATTARA, Minh LE HUY
Laboratory of Analytical Chemistry of Space and Energy Physics (LAC@PSE); Université Norbert ZONGO; Institute of Geophysics, Vietnamese Academy of Science and Technology
Abstract: The study of equatorial ionospheric scintillation at the GPS stations of Koudougou and Baclieu , stations located in the equatorial region from 2015 to 2019, was carried out using the ROTI index. The ROTI index is one of the indices used to characterize the phase fluctuations responsible for phase scintillations when GPS satellite signals encounter ionospheric irregularities as they cross the ionosphere. Low ROTI values are generally observed from 0300 TL to 1930 TL for all years, with ROTI values ranging from 0 to 0.4 tecu/mn. The time interval during which low ROTI values are recorded can vary, starting late (0300TL) and ending early (before 1930TL) or late (after 1930 TL). Maximum ROTI values (ROTI ≥0.5 tecu/mn) are recorded before sunrise from 0000TL to 0200TL and after sunset, from 19:30 to 2300TL, which characterizes the presence of strong scintillations. Strong scintillations are observed at the equinoxes. In the case of the equatorial ionosphere, it is accepted that the Rayleigh-Taylor instability mechanism is the main cause of the ionization irregularities that develop after sunset.
Keywords: Scintillation, ROTI index, equinoxes, ionospheric irregularity
Translated with DeepL.com (free version)
Author(s): Shradha Mohanty, M.Mainul Hoque
German Aerospace Center (DLR); German Aerospace Center (DLR)
Abstract: GNSS radio occultation (RO) observations conducted on board low-earth orbit (LEO) satellites are widely used in many atmospheric applications, including ionospheric and space weather research. Utilizing information from four satellites/missions, we have employed a multi-satellite, multi-instrument strategy to detect ionospheric irregularities causing scintillations over the low-latitude equatorial region. We used the electron density (Ne) and total electron content (TEC) profiles from COSMIC-2, as well as high rate 50 Hz atmospheric phase (conPhs) with signal to noise ratio (SNR) measurements along GNSS-RO ray-path obtained by STRATOS reciever onboard Spire’s CubeSats constellation. Equatorial plasma bubbles in the post-sunset sector are identified using the nighttime disk images from the Global-scale Observations of the Limb and Disk (GOLD) mission. We also took advantage of the availability of the Ion Velocity Meter (IVM) instrument from Ionospheric Connections Explorer (ICON), which provides electron density in-situ data.
The GNSS-RO high rate conPhs files from Spire and the COSMIC-2 ionPrfs are accessed via the University Corporation for Atmospheric Research (UCAR) data repository. The onboard amplitude scintillation detection method in Spire CubeSats allows continuous recording of 50 Hz phase and pseudorange data up to satellite orbit height, and such data are levelled as “extended profiles”. At present, this functionality is restricted only to the GPS constellation. Amplitude scintillation index S4 derived from the 50 Hz SNR data of the extended profiles, is used to detect the F-layer amplitude scintillations.
We applied an irregularity detection technique to the TEC and COSMIC-2 Ne profiles, which reach altitudes in the F-layer as well. We have additionally detected irregularity events after sunset using the ICON in-situ electron density data. The equatorial plasma bubbles seen in the GOLD images, and in the COSMIC-2 and ICON observations are closely related in both space and time. Our study shows that the GNSS-RO data from commercial CubeSats can be used in concert with other satellite missions, such as GOLD data, to enhance and augment ionospheric scintillation research conducted by COSMIC-2 and other RO missions.
Author(s): Konstantin Kabin, Alex C. Cushley, Jean-Marc Noel
Royal Military College of Canada; Royal Military College of Canada; Royal Military College of Canada
Abstract: Most commercial airplanes are equipped with Automatic Dependent Surveillance Broadcast (ADS-B) which is used by the air traffic control to supplement or replace secondary surveillance radar observations and by other aircraft for traffic situation awareness. A similar system for commercial ships is the Automatic Identification System (AIS) which is used by the International Maritime Organization to monitor the ships’ locations and help to avoid collisions. Both of these emit linearly polarized VHF signals (with frequencies of 1090, or 978 MHz for ADS-B and 161.975, or 162.025 MHz for AIS) which are detectable by low Earth orbiting satellites. Linearly polarized radio waves experience Faraday rotation when propagating along the terrestrial magnetic field. By measuring the Faraday rotation angle the total electron content (TEC) of the ionosphere can be inferred.
ADS-B and AIS signals are currently underused for monitoring the ionosphere so they present an exciting opportunity. These signals have the advantage of providing data in the ocean regions where it is not possible to deploy stationary GPS receivers. Although these signals are, naturally, heavily concentrated on most popular routes used by airlines and maritime trade, they allow a meaningful extension of the existing land-based GPS arrays. Additionally, since Faraday rotation depends not only on TEC, but also on the electron density distribution along the magnetic field lines, it may be possible to combine ADS-B/AIS data with GPS TEC measurements to infer some information about the vertical structure of the ionosphere. Finally, with multiple signals and receivers it would be possible to use tomography to analyze ionospheric spatial structure.
Author(s): Tshimangadzo Merline Matamba, Donald W. Danskin
1 South African National Space Agency (SANSA), Hermanus 7200, South Africa.; South African National Space Agency (SANSA), Hermanus 7200, South Africa
Abstract: The ionosphere is part of the atmosphere consisting of electrically charged particles (electrons and ions) that affect how radio waves propagate from the satellite to ground-based receivers. During severe space weather conditions, the electron density varies due to the changes in the electron distribution during the storm. The South African National Space Agency (SANSA) near-real-time products are used to monitor the total electron content (TEC), critical frequency of the F2 layer (foF2), and gradients in TEC. The spatial gradients are observed to be non-uniform over Southern Africa and vary depending on the phase of the geomagnetic storm and the season. The TEC from the near-real-time TEC maps is compared with the TEC estimated from the South African ionosondes, and the TEC from the AfriTEC model.
Author(s): Piero Diego, Davide Badoni, Cristian De Santis, Alexandra Parmentier, Gianmaria Rebustini, Fabrizio De Angelis, Mirko Piersanti, Emanuele Papini, Roberto Ammendola, Emiliano Fiorenza, Giulia D’Angelo, Igor Bertello, Pietro Ubertini
INAF-IAPS; INFN-Sezione di Roma “Tor Vergata”; INFN-Sezione di Roma “Tor Vergata”; INAF-IAPS; INFN-Sezione di Roma “Tor Vergata”; INAF-IAPS; University of l’Aquila; INAF-IAPS; INFN-Sezione di Roma “Tor Vergata”; INAF-IAPS; INAF-IAPS; INAF-IAPS; INAF-IAPS
Abstract: The China Seismo-Electromagnetic Satellite (CSES) mission relies on an ionospheric constellation aiming to measure the electromagnetic fields, plasma and charged particles. The primary task of the mission is to improve our understanding of ionospheric variability induced by forcing of both external and internal origin. The first spacecraft, CSES-01 (launched in 2018), is currently in operation, and CSES-02 is scheduled to be launched at the end of 2024. The satellites, 3-axis attitude stabilized, are designed to operate in a 98° Sun-synchronous (14-02 LT) circular orbit at an altitude of 500 km. The peculiar orbit allows the monitoring of both latitudinal and day-night ionospheric variabilities during the occurrence of the various forcings. Among the various instruments on board the CSES satellites, the Electric Field Detector (EFD) deserves a special mention for its design and performance. Based on the dual-probe technique, its four spherical sensors are located at the tips of four booms of 4.5 m, thus allowing the detection of the three components of the ionospheric electric field and avoiding S/C interferences on such delicate measurements. Electric field components are collected in the frequency range from quasi-DC up to 3.5 MHz. The entire range is collected as waveforms and spectra and divided into different bands in order to maximize the scientific information despite the data budget limit induced by the highest frequency. Finally, novel technical features allow for obtaining an unprecedented resolution in the observed parameters.
at high latitudes.
Specifically, this contribution will highlight EFD ability to monitor even small variations in space plasma potential. This enables a detailed description of plasma structures and dynamics, such as Field Aligned Current and Auroral Oval Boundary configurations; and it gives insight into the generation of sporadic structures, such as Equatorial Plasma Depletions and ionospheric irregularities at high latitudes.
Author(s): Mahith Madhanakumar, Andres Spicher, Juha Vierinen, Kjellmar Oksavik, Kjellmar Oksavik, Anthea J. Coster, Devin Ray Huyghebaert, Devin Ray Huyghebaert, Carley J. Martin, Ingemar Häggström, Larry J. Paxton
Department of Physics and Technology, UiT The Arctic University of Norway; Department of Physics and Technology, UiT The Arctic University of Norway; Department of Physics and Technology, UiT The Arctic University of Norway; University of Bergen; Arctic Geophysics, University Centre in Svalbard; Haystack Observatory, Massachusetts Institute of Technology; Department of Physics and Technology, UiT The Arctic University of Norway; Institute of Space and Atmospheric Studies, University of Saskatchewan; Institute of Space and Atmospheric Studies, University of Saskatchewan; EISCAT Scientific Association; The Johns Hopkins University Applied Physics Laboratory
Abstract: The ionospheric impact on radio signals from Global Navigation Satellite System (GNSS) are of growing concern for the modern society that heavily depends on services such as positioning, navigation and timing (PNT). Irregularities with scale sizes ranging from a few hundred meters to kilometers are capable of inducing rapid perturbations in the amplitude and phase of L-band signals causing scintillation, which at times can result in signal loss-of-locks and disruption to continuous signal tracking by the receiver. Predicting or developing mitigation strategies for scintillation events would therefore require an understanding of the ionospheric conditions that can likely produce irregularities over a wide spectrum of scale sizes and sufficient strengths capable of affecting GNSS signals. We therefore conducted a multi-instrument study to investigate the evolution of scintillation strengths and the associated conditions at the high latitude polar ionosphere.
During weak geomagnetic conditions, the analysis revealed simultaneous occurrence of intense levels of amplitude and phase scintillation in multiple GNSS signals. Intense scintillation was observed to start in the pre-noon sector and was asssociated with the poleward transport of polar cap patchs from lower latitudes. Observation from the EISCAT Svalbard radar (ESR) revealed the dense plasma structures to be co-located with regions of strong Joule heating and soft precipitation. Furthermore, a significant suppression in the scintillation strengths in the post-noon sector was observed when a depleted region of ionospheric plasma was transported into the polar ionosphere from the dawn sector when the IMF By and Bz components exhibited strong reversals.
Through this study, we show that even weak geomagnetic storms can result in adverse space weather effects and IMF/geomagnetic conditions alone cannot fully capture its impact on GNSS radio signals.
Author(s): Jean de Dieu Nibigira
University of Alberta
Abstract: In this presentation, the inference of ionospheric electron density profiles and other quan-
tities are presented and discussed. Nearest neighbor (NN) and Radial Basis Function
(RBF) regression methods were used separately and then the combination of the
two methods. The training and validation data sets were constructed using a one
hundred thousands data set from IRI 2020 model with randomly chosen years (1987-
2022), months (1-12), days (1-31), latitudes (-60 to 60°), longitudes (0,360°), times
(0-23h) and altitudes (85-600km). For comparison with another constructed model
to infer ionospheric parameters, we also used a set of real data from ISR measure-
ments that were provided by Prof. John Bosco Habalurema at Rhodes University
and SANSA in South Africa. In addition to the ionospheric electron density profiles,
both methods were also used to infer some other ionospheric parameters such as the
effective mass, electron and ion temperatures that are not provided by the vertical
incidence ionosondes instruments. The presented results showed that the inference
of ionospheric electron is better with NN method than with RBF method or their
combination. Best and worst cases for each method are plotted, compared and dis-
cussed in this thesis. It is depicted that the relative error is generally between 5
and 15 percents for best and worst cases, respectively. The nearest neighbor method
overestimates the inferred electron density, the effective mass and the temperature
predictions especially at higher altitudes and higher density values in general, but
slightly underestimates them or match them at lower density values and lower alti-
tudes. Moreover, it is observed that the nearest neighbor method infers the effective
mass, the electron and ion temperatures with lower relative errors than the electron density profiles. The use of the combination of the NN method with the RBF method
only improves the results at the peak values (altitude and density) of the electron den-
sity profiles. In some cases, at the higher altitude the predictions/inferences of the
electron density profiles are improved compared to the inference from separate NN
or RBF method.
Author(s): Jaroslav Urbar, Šimon Mackovjak, Patrick Hannawald, Carsten Schmidt, Lisa Küchelbacher, Jaroslav Chum, Vladimír Truhlík, Petra Koucká Knížová, Ján Kubančák, Sabine Wüst, Michael Bittner
Institute of Atmospheric Physics ASCR, Prague, Czech Republic; Slovak Academy of Sciences, Institute of Experimental Physics, Košice, Slovakia; Deutsches Zentrum für Luft- und Raumfahrt e.V., Oberpfaffenhofen, Germany; Deutsches Zentrum für Luft- und Raumfahrt e.V., Oberpfaffenhofen, Germany; Deutsches Zentrum für Luft- und Raumfahrt e.V., Oberpfaffenhofen, Germany; Institute of Atmospheric Physics ASCR, Prague, Czech Republic; Institute of Atmospheric Physics ASCR, Prague, Czech Republic; Institute of Atmospheric Physics ASCR, Prague, Czech Republic; Slovak Academy of Sciences, Institute of Experimental Physics, Košice, Slovakia; Deutsches Zentrum für Luft- und Raumfahrt e.V., Oberpfaffenhofen, Germany; Deutsches Zentrum für Luft- und Raumfahrt e.V., Oberpfaffenhofen, Germany
Abstract: The day-to day variability of quiet-time ionosphere is surprisingly high even during periods of negligible solar forcing. Relatively well understood is the high-latitude variability where the solar wind is directly driving the high latitude currents, convection electric field or polar aurorae. But the current understanding does not allow to accurately model the ionospheric state during the quiet-time conditions also at mid- and low-latitudes. Surprising effects remain even at mid-latitudes, including for instance double daily maxima of ionospheric critical frequency.
SWARM measurements allow the characterization of the upper atmospheric conditions and dynamics for more than 10 years now. The analysis of SWARM data also showed that the ionosphere is sometimes disturbed even during “quiet” solar periods: the electron density and electric field, for instance, can show significant variability that currently remains unexplained.
Using SWARM data, supported by extensive ground-based measurements of both the upper mesospheric/ lower thermosphere (UMLT) and ionospheric D-, E- and F-region, we contribute to characterize the atmospheric state during these quiet periods. Thus, QUID-REGIS contributes to the understanding of disturbances in the upper atmosphere and clarifies whether these are at least in parts a result of neutral atmospheric dynamics from the lower atmosphere at mid-latitudes.
During solar quiet periods, we will analyze SWARM data to detect unexpected variability. For these periods, we will investigate measurements at lower heights for atmospheric and ionospheric variability. These measurements comprise airglow observations representative for the neutral atmosphere in the UMLT(80-100km), magnetic field (and other) observations representative for the ionospheric dynamo region(85-200km) as well as airglow observations, Doppler sounding and ionosonde measurements from about 100 to 350km altitude.
Whenever we detect unexpected variability in SWARM data we statistically evaluate if the lower atmosphere might serve as a source region for these variabilities. Then, atmospheric waves may serve as an explanation. We will derive and analyze well-established indices of planetary wave and gravity wave dynamics in the UMLT to characterize those waves and quantitatively estimate their contribution to the observed variability in the ionosphere. We then evaluate, if the disturbances in the ionosphere during the quiet periods are causing less accurate outputs of the IRI-model, in such case we would provide the improved version of IRI model based on Swarm electron density data. We aim to deliver the typical quantities of the dynamics as a look-up table to contribute to modeling of the baseline conditions.
In summary, a better quantification of the role of UMLT wave dynamics in the occurrence of solar quiet ionospheric disturbances will be achieved along with a better representation of baseline ionospheric conditions.
Author(s): Andreas Strasser, Sandro Krauss, Felix Öhlinger, Barbara Süsser-Rechberger
Graz University of Technology, Institute of Geodesy; Graz University of Technology, Institute of Geodesy; Graz University of Technology, Institute of Geodesy; Graz University of Technology, Institute of Geodesy
Abstract: Since the launch of the CHAMP satellite in July 2000, it has been continuously possible to derive thermospheric neutral densities from satellite measurements. This can be achieved by several different methods. At Graz University of Technology, three different approaches are currently in use. The most precise strategy available is based on accelerometer measurements. At the moment we only use these for GRACE-FO-1. As an additional method, on-board GNSS measurements are used to calculate densities from precise kinematic orbits. Sufficiently accurate orbits are processed and published by our working group for several satellite missions. Since 2024, we have also been using SLR observations to obtain density information.
The resulting datasets are used to improve the understanding of the coupled magnetosphere-ionosphere-thermosphere system. Since space weather strongly influences this system, its response to (changes in) solar activity is of great interest. Several solar events of the last decades are analysed and discussed.
Author(s): Anna Morozova, Luca Spogli, Rayan Imam, Emanuele Pica, Juan Andrés Cahuasquí, Mohammed Mainul Hoque, Norbert Jakowski, Daniela Estaço
IA-UC, University of Coimbra, Portugal; INGV, Rome, Italy; INGV, Rome, Italy; INGV, Rome, Italy; Institute for Solar-Terrestrial Physics, DLR, Neustrelitz, Germany; Institute for Solar-Terrestrial Physics, DLR, Neustrelitz, Germany; Institute for Solar-Terrestrial Physics, DLR, Neustrelitz, Germany; Departamento de Física da University of Aveiro, Aveiro, Portugal (at the time research was conducted)
Abstract: Mid-latitudes are usually considered as less prone to the occurrence of ionospheric irregularities affecting the reliability of Global Navigation Satellite System (GNSS) signals. However, being a densely populated area, there is an increasing interest in correctly evaluating the impact of such classes of phenomena. In such a perspective, we analyse the case of the geomagnetic storm of June 22-23, 2015 over the Western Mediterranean area. That event caused a rare phenomenon of a spill-over of equatorial plasma bubbles (EPBs) well north from their usual region, being an area of about ~+/- 20º around the magnetic equator. We analyse this event using data from ground-based GNSS receivers, from which we evaluate the amplitude scintillationS4 and the Rate Of Total Electron Content change (ROTI) indices. The simultaneous use of the two indices allows speculating on the scale sizes of the found irregularities. Furthermore, these data are complemented with the in situ information provided by the ESA’s Swarm satellites, which measures the plasma density at the satellite heights and has, among its data products, an ionospheric plasma bubble index, able to reveal the presence of EPBs. Two new Swarm products recently developed namely TEGIX and NEGIX using GNSS and electron density measurements onboard Swarm satellites A and C. The TEGIX measures spatial total electron content (TEC) gradients in the topside ionosphere whereas the NEGIX measures the spatial electron density gradients at the satellite height. TEGIX and NEGIX data products will be investigated for any possible signatures of plasma bubbles during the specified storm event.
The multi-source data allows for a better understanding of the ionospheric dynamic during the studied event, and identification and characterization of the ionospheric plasma bubbles that reached middle latitudes near the Iberian Peninsula during the studied event.
Author(s): Iurii Cherniak, Irina Zakharenkova, Douglas Hunt
COSMIC Program Office, University Corporation for Atmospheric Research; COSMIC Program Office, University Corporation for Atmospheric Research; COSMIC Program Office, University Corporation for Atmospheric Research
Abstract: The Radio Occultation (RO) observations from GNSS receivers onboard LEO satellites have been successfully used for different Space Weather and Space Climate applications for over 25 years. But RO approach can be also effective for sounding of the Earth’s ionosphere from the geostationary orbit when radio signals tracked from GPS transmitters on the opposite side of the Earth. In this study, we present results of RO technique applied to GPS measurements from the GOES satellites recorded onboard the Geostationary Operational Environmental Satellites (GOES) mission operating at ~35800 km altitude. The GOES satellites are equipped by GPS receivers for navigation and orbital maneuvers tracking but not for remote sensing applications.
We demonstrate how GPS signals propagated through the Earth’s atmosphere and tracked by the GOES GPS receivers can be used to retrieve the vertical distribution of plasma density in the ionosphere (electron density profiles, EDPs) by RO technique and for the detection of ionosphere plasma irregularities developed as ionospheric response to the Space Weather events.
One of the features of RO sounding form the geostationary orbit is that geographical distribution of the retrieved GEO-RO-based EDPs is uniquely constrained and repeatable in the Earth-Centered-Earth-Fixed reference frame with respect to the GPS constellation orbiting. Such EDPs from GEO have provide opportunity to generate unique temporal and spatial atmospheric measurements complementary to those from the LEO space-based receivers. Another advantage of GOES geosynchronous configuration of RO sounding for regular ionosphere monitoring and climatological studies is that obtained ionospheric EDPs have a maximum altitude up to 1000–2000 km, much higher than any existing LEO RO missions.
The GPS receivers onboard the GOES satellites track the GPS signals propagated through the Earth’s ionosphere, and it allows us to analyze rapid variations of TEC along these links, which can be caused by ionospheric plasma gradients and ionospheric irregularities. Using the novel geostationary GOES GPS observations, we examined signatures of the ionospheric irregularities’ occurrence for two major geomagnetic storms that occurred in September 2017 and August 2018. The presence of ionospheric plasma density irregularities in the vicinity of GOES GPS RO sounding field-of-view during main phases of both geomagnetic storms and their absence during quiet pre-storm conditions were confirmed by Rate of TEC (ROTI) maps constructed with multi-station ground-based GNSS observations. So, the GPS RO observations with geostationary configuration can provides new opportunities for detection of ionospheric irregularities and ionospheric density gradients for the Space Weather applications.
Author(s): Dmytro Vasylyev, Martin Kriegel, Paul David
DLR Institute for Solar-Terrestrial Physics; DLR Institute for Solar-Terrestrial Physics; DLR Institute for Solar-Terrestrial Physics
Abstract: Radio-frequency electromagnetic waves can undergo random modulations of amplitude and phase as they propagate through the randomly inhomogeneous ionosphere. This effect, known as scintillation, can drastically affect the performance and robustness of many services ranging from precise positioning to communications. In our institute, we are working on the operational provision of not only the empirical scintillation levels, but also the scintillation model that can provide global coverage and would be useful for short-term scintillation prediction.
Recently we have acquired the Global Ionospheric Scintillation Model (GISM), which is based on the multiple random phase screen method [1]. Currently, this model is only able to cover the low-latitude regions, and our efforts are focused on extending the model to high and polar latitudes before it can be put into operational service. For this purpose, it is planned to use the recently developed method of phase gradient screens, which allows to simulate the refractive type of scintillation caused by scattering on strong ionospheric gradients [2]. The climatology of the required gradient field will be derived from the in-situ electron density measurements on board the Swarm satellites over a period of 10 years. In this context, the method of empirical orthogonal functions is used to relate the gradient values to the relevant driving parameters such as solar flux index, solar wind coupling parameter, geomagnetic field strength, etc.
References:[1] D. Vasylyev et al., “Modeling of ionospheric scintillation”, JSWSC, 12, 22 (2022).[2] D. Vasylyev et al., “Scintillation modeling with random phase gradient screens”, accepted by JSWSC.
SWR4-p50 Unexpected Energization in the Auroral Ionosphere during Periods of Disturbed Space Weather
Author(s): Francesca Di Mare, Gregory G. Howes
NASA GSFC/CUA; University of Iowa
Abstract: The Twin Rockets to Investigate Cusp Electrodynamics (TRICE-2), launched from Norway’s Andøya Space Center on December 8, 2018, have led to the discovery of a new type of turbulence in the Earth’s polar ionosphere. This turbulence consists of waves moving up and down the Earth’s magnetic field lines, called inertial Alfvén waves. By combining the rockets’ measurements of the turbulent electric field with that of the turbulent magnetic field, we deduced that the turbulent energy flows to small scales along a pathway that is different from previous observations of turbulence in space. Rather than solely energizing electrons through a process called Landau damping, the properties of the turbulence inferred from the TRICE-2 observations suggest the turbulence can also energize the protons in the ionospheric plasma through a mechanism called cyclotron damping. Thus, these TRICE-2 rocket observations provide a solid foundation for the unexpected energization of protons in the ionospheric plasma during periods of disturbed space weather.
Author(s): Kitti Alexandra Berényi, Loredana Perrone, Dario Sabbagh, Carlo Scotto, Alessandro Ippolito, Árpád Kis, Veronika Barta
HUN-REN-ELTE Space Research Group, Budapest; HUN-REN Institute of Earth Physics and Space Science, Sopron; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Roma, Italy; HUN-REN Institute of Earth Physics and Space Science, H-9400 Sopron, Hungary; HUN-REN Institute of Earth Physics and Space Science, H-9400 Sopron, Hungary
Abstract: A comparison of three types of ionosonde data from Europe during an interplanetary coronal mass ejection (ICME)- and a corotating interaction region (CIR)-driven geomagnetic storm event is detailed in this study. The selected events are 16–20 March 2015 for the ICME-driven storm
and 30 May to 4 June 2013 for the CIR-driven one. Ionospheric data from three European ionosonde stations, namely Pruhonice (PQ), Sopron (SO) and Rome (RO), are investigated. The ionospheric F2-layer responses to these geomagnetic events are analyzed with the ionospheric foF2 and h’F2 parameters, the calculated deltafoF2 and deltahF2 values, the ratio of total electron content (rTEC) and Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite Global Ultraviolet Imager (GUVI) thermospheric [O]/[N2] measurement data. The storm-time and the quiet-day mean values are also compared, and it can be concluded that the quiet-day curves are similar at all the stations while the storm-time ones show the latitudinal dependence during the development of the storm. As a result of the electron density comparison, during the two events, it can be concluded that the sudden storm commencement (SSC) that characterized the ICME induced a traveling atmospheric disturbance (TAD) seen in the European stations in the main phase, while this is not seen in the CIR-driven ionospheric storm, which shows a stronger and more prolonged negative effect in all the stations, probably due to the season and the depleted O/N2 ratio.
Author(s): Claudia Borries, Pelin Iochem
German Aerospace Center – DLR; German Aerospace Center – DLR
Abstract: Recently, a persistent solar wind impact on the variability of the high latitude ionosphere has been reported for the Tromsø station. Since the electrodynamic processes in high latitudes impact the ionosphere and thermosphere conditions globally, the solar wind forcing is part of the variability of the global ionospheric electron density. This can be shown by correlation analyses performed between the Kan-Lee merging electric field (a solar wind – magnetosphere coupling function) and the Total Electron Content obtained from the IGS maps. We present correlation results for a high solar for an example day in 2013, a year of high solar activity during 24th solar cycle.
The global patterns of the persistent solar wind impact on the ionosphere vary with geomagnetic latitude, season and local time. These patterns agree well with the typical ionospheric storm climatology. Our results show that the solar wind variability is a relevant parameter to consider for the modelling of TEC.
Author(s): Sara Mainella, Pietro Vermicelli
INGV; SpacEarth Technology
Abstract: In our previous report [1], we identified which ground-based and space-borne infrastructures are susceptible to upper atmospheric phenomena (UPA) and conducted a critical comparison of the related socioeconomic estimates found in the literature. This issue is increasingly important, given the growing reliance of modern society on technologies vulnerable to space weather events.
Our findings indicated that the financial implications of UPA risks to essential space-borne and ground-based systems are substantial. Moreover, the literature predominantly addresses events with low return probabilities (1-30, 100, or 1000-year events, as defined in [2]). We also noted that the science of quantifying the socioeconomic impacts of UPA is still underdeveloped, lacking crucial modeling data partly due to the limited experience of contemporary society with extreme events, often resulting in reliance on qualitative assumptions [3]. To overcome these challenges and considering the upcoming peak of sunspot activity in the current solar cycle, expected in 2025, we have decided to focus on UPA that occur during moderate space weather events. These occurrences and their propagation forecasts are increasingly studied, for instance, within the EU-funded (GA 101081835) T-FORS project. These UPA, known as Traveling Ionospheric Disturbances (TIDs), are particularly relevant for assessing socioeconomic impacts because they are considered the “silent killers of accuracy” in critical services such as GNSS precise positioning using PPP or RTK techniques.
To illustrate our point, we present a case study. The St. Patrick’s Day storm on March 17, 2015, was the most severe geomagnetic storm of the 24th solar cycle, with a Dstmin index of approximately -226nT, making it an event with an annual occurrence probability [2], hence a moderate one. Poniatoski et al. [4] examined the impact of Medium-Scale TIDs (MSTIDs) on the kinematic PPP of GNSS stations across central Europe, finding a significant reduction in positional accuracy—worse than 1.5 meters for all components—during the storm’s main phase when high-intensity MSTIDs were present. This reduced accuracy was so pronounced that accurate positioning was impossible for over three hours. Considering that many GNSS applications and technologies in precision agriculture (PA) require positional accuracy of less than 1 meter [5] and that a one-hour GNSS outage can cost the PA sector around €200,000 (according to authors’ estimates), the St. Patrick’s Day storm likely incurred costs of about €600,000 for this sector. By extrapolating from this example, we can address the broader question of how expensive the impact of MSTIDs on GNSS positioning might be. We will begin by creating a more general assessment of the expected decline in positional accuracy and the duration of these declines under various storm scenarios. From there, we will achieve our objective by integrating this information with the GNSS requirements across different sectors and utilizing existing methods [3] to estimate the socioeconomic costs of GNSS outages caused by MSTIDs.
Author(s): Veronika Haberle, Aurélie Marchaudon, Aude Chambodut, Pierre-Louis Blelly
Conrad Observatory, GeoSphere Austria; Institut de Recherche en Astrophysique et Planétologie (IRAP), CNRS; Université de Strasbourg, CNRS; Institut de Recherche en Astrophysique et Planétologie (IRAP), CNRS
Abstract: Ground magnetic field measurements have a long history of being used to determine the geoeffectiveness of space weather events. However these measurements are made up of a superposition of a vast amount of magnetic sources originating inside and outside the Earth.
In the absence of space weather driving, the geomagnetic field follows smooth variations induced by quiet sources like the internal secular variation and external solar quiet current system that originates in the mid-latitudinal ionosphere. In order to describe these variations, and thus characterise the quiet sources, geomagnetic baselines are put in place, often used as a first step in deriving magnetic activity indices.
As the need for operational space weather nowcasting and situational awareness increases, the need for accurate determination of intensity and duration of space weather events increases too.
In this contribution we present the algorithm to produce the (near) real-time geomagnetic baseline and its applicability to mid- to low latitudinal observatories. Furthermore we show which sources are contained within the baseline and for which purposes it can be deployed.
Among others the introduced baseline allows for the operational identification of solar forcing intensities and may also be used for derivation of magnetic indices that use magnetic field data from low- to mid-latitudinal observatories.
Author(s): Slaviša Živković, Giuliana Verbanac, Mario Bandić, Ljiljana Ivanković
State School Franjo Hanaman, Drenovci, Croatia; Faculty of Science University of Zagreb, Department of Geophysics, Croatia; Faculty of Science University of Zagreb, Department of Geophysics, Croatia; University of Applied Sciences Velika Gorica, Croatia
Abstract: We present the graphical user interface (GUI) that we designed and developed to determine the plasmapause crossings based on all four CLUSTER satellites. For the time period 2002-2018 we used electron densities obtained from WHISTLER instrument, spacecraft potential obtained from EFW instrument, magnetic field measured by FGM, satellite position, L-shell parameter and WHISPER spectrograms from Cluster Science Archive. Knowing the plasmapuse position is very important for space weather foercasting.
The determination of CLUSTER plasmapause crossings are based on the electron density profile which are at CSA often given only up to 30 cm-3 which does not enable to detect the plasmapause position that can be e.g. at 100 cm -3. We aim to derive the full density profile or at least as high as possible density values from the spacecraft potential. The deduced electron density are checked using the WHISPER spectrograms.
The developed GUI enables usage of standard different tools such as zoom, pan, saving fits parameters, offers different options for saving density gradients.
The first tests have shown that GUI enables for determining plasmapause crossing accurately, as far as possible based on available CLUSTER data given at CSA.
Developed GUI has a potential to contribute to use as much as possible data from CLUSTER mission.
This study is supported by ESA project: “Deducing plasmaspheric wind using CLUSTER satellite” (ESA Contract No: 4000144006/24/NL/EH/yd).
Author(s): Arthur Amaral Ferreira, Claudia Borries, Renato Alves Borges
German Aerospace Center, Institute for Solar-Terrestrial Physics, Neustrelitz, Germany; German Aerospace Center, Institute for Solar-Terrestrial Physics, Neustrelitz, Germany; Department of Electrical Engineering, University of Brasilia, Brazil
Abstract: Frequently observed during geomagnetic storm events, the Large Scale Travelling Ionospheric Disturbances (LSTIDs) correspond to wave-like perturbations in the ionospheric electron density. They are the signatures in the ionosphere of Atmospheric Gravity Waves triggered due to the dissipation of energy and momentum in the auroral region during geomagnetic storms. Several investigations of the phenomena have been performed during the last decades in order to characterize its magnitude, frequency of occurrence and propagation parameters for different longitudinal sectors using different instruments. Recently, a new index based on Global Navigation Satellite Systems (GNSS) measurements has been proposed, which allows statistical analysis of TIDs occurrence and prediction of TID activity at mid-latitude Europe. One of the methodologies proposed for predicting the TID activity index is based on a linear regression approach and uses historical values of solar wind measurements obtained from the Lagrangian point L1 in order to predict the TID activity level for different lead times. So far, the prediction of the TID activity index has been demonstrated for a single station in mid-latitude Europe only. Here, we evaluate the performance of the prediction model for different longitudinal sectors and investigate how it varies for the different sectors.
Author(s): Joana Pereira, Isabel Fernandez Gomez, Claudia Borries, Michael Schmidt, Frank Heymann
Institute of Solar-Terrestrial Physics, German Aerospace Center, Neustrelitz, Germany; Institute of Solar-Terrestrial Physics, German Aerospace Center, Neustrelitz, Germany; Institute of Solar-Terrestrial Physics, German Aerospace Center, Neustrelitz, Germany; Deutsches Geodätisches Forschungsinstitut (DGFI-TUM), TUM School of Engineering and Design, Technical University of Munich, Munich, Germany; Institute of Solar-Terrestrial Physics, German Aerospace Center, Neustrelitz, Germany
Abstract: Space weather events (SWE) that result in geomagnetic storms influence electromagnetic wave propagation in the Earth’s ionosphere and atmosphere, affecting communications, navigation, and positioning. Forecasting the state of the upper atmosphere and conditions following SWE is one of the key aspects to protect the current high technological society. However, accurately representing the thermosphere-ionosphere (TI) system is challenging due to its complex interactions with the lower atmosphere and the magnetosphere that are challenging to correctly represent. SWE events have often been poorly observed which can lead to uncertain conclusions about these phenomena. TI modeling is essential for understanding the complex coupling interactions between thermosphere and ionosphere to predict and mitigate SWE effects. Model validation is crucial to assess the capabilities of these models and to develop new modelling techniques. It shows the model’s performance and identifies errors which can be caused by factors such as the solar cycle, daily or seasonal variability and other biases. So far, there is no standard set of validation tools or reference datasets that can be used in the TI domain. In this work Ionospheric radio occultation data (electron density) from COSMIC2 mission serves as the basis for validating the two models, (1) International Reference Ionosphere (IRI) and (2) the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM). A set of verification and statistical methods is used to evaluate these models under various conditions (geomagnetically quiet and active) and periods (seasonal variations). The outcome of this study is an initial model validation framework that employs different statistics and metrics, allowing the comparison of the models performance.
Author(s): Alessandro Ippolito, Dario Sabbagh, Loredana Perrone, Carlo Scotto, Maria Graciela Molina, Marco
Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143 Rome, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143 Rome, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143 Rome, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143 Rome, Italy; 1. Tucumán Space Weather Center (TSWC), Facultad de Ciencias Exactas y Tecnología (FACET), Universidad Nacional de Tucumán (UNT), Av. Independencia 1800, Tucumán, Argentina. 2. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina. 3. Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143 Rome, Italy.; Tucumán Space Weather Center (TSWC), Facultad de Ciencias Exactas y Tecnología (FACET), Universidad Nacional de Tucumán (UNT), Av. Independencia 1800, Tucumán, Argentina.
Abstract: The response of the ionosphere-thermosphere system in the European sector has been investigated for two moderate geomagnetic storms occurred respectively on 6 and 19 May 2023. Ionospheric parameters foF2 and hmF2 were used to study the behavior of the ionosphere in relation to the geomagnetic storms. In addition, solar wind conditions have been analysed to better understand the source and the evolution of such storms. Ionosonde data acquired in the North American sector were also studied for comparison. To better understand the role of aeronomic parameters in the formation mechanisms of the geomagnetic storms, we used a technique based on ionosonde observations in the ionospheric F region and neutral plasma density from Swarm satellite observations, to retrieve the thermospheric neutral composition ([O], [N2], [O2]), the exospheric temperature Tex, and the vertical plasma drift. We observed that both geomagnetic storms triggered negative and positive phases in the ionospheric parameters in the northern hemisphere, as can be deduced by the analysis we performed of manually validated ionosonde data. The F2-region electron density variations in the Earth’s northern hemisphere during the 6 and 19 May storms, can be mainly due to neutral composition, temperature and thermospheric wind modifications induced by the geomagnetic storms.
Author(s): Marcus N. Pedersen, Heikki Vanhamäki, Anita Aikio, Lei Cai, Milla Myllymaa
University of Oulu; University of Oulu; University of Oulu; University of Oulu; University of Oulu
Abstract: Understanding both the spatial and temporal dynamics of the near-Earth space environment is important for successful forecasting of space weather. One example is the auroral Joule heating which causes thermal expansion of the upper atmosphere, increasing the thermospheric density and causes low Earth orbiting (LEO) satellites to experience more drag. This chain of events often begin as geoeffective solar wind transients such as high-speed stream/stream interaction regions (HSS/SIR) or interplanetary coronal mass ejections (ICME) impact Earth’s space environment. The “Joule heating effects on ionosphere-thermosphere coupling and neutral density (JOIN)” research project is part of ESA’s “4D Ionosphere” initiative. The JOIN project has four science objectives:
Determine the global statistical distribution and variability of the high-latitude Joule heating during geomagnetic storms driven by HSS/SIR or ICMEs.
Correlate the storm-time Joule heating with observed large-scale atmospheric density variations at LEO.
Estimate variations in the atmospheric scale height by directly comparing density measurements from two different altitudes during co-planarity periods between various LEO satellites at polar orbits.
Perform event studies of meso-scale Joule heating and density variations at auroral regions by utilizing conjunctions between Swarm satellites and incoherent scatter radars (e.g., EISCAT, EISCAT3D and Poker flat).
This poster presentation will focus on the preliminary results related to the two first science objectives. Based on superposed epoch analysis of 231 geomagnetic storms between 2014 and 2024, it is found that the Joule heating in the ionospheric E-region and neutral density enhancements at the altitude of the Swarm and GRACE satellites show different characteristics depending on the geomagnetic storm driver. The Joule heating has a faster increase at the beginning of the storm main phase when the storm is initiated by a HSS/SIR or sheath region of ICMEs, while a more gradual and longer lasting increase is found in storms driven by magnetic clouds within ICMEs. This is inline with previous results of the total field-aligned and ionospheric currents during storms (Pedersen et al., 2021, 2022). The thermospheric density enhances gradually during the storm main phase and the enhancements are typically largest and longest-lasting for storms driven by MC due to the prolonged interval of increased Joule heating.
Author(s): Zbyšek Mošna, Veronika Barta, Kitti Alexandra Berényi, Jens Mielich, Tobias Verhulst, Daniel Kouba, Jaroslav Urbář, Jaroslav Chum, Petra Koucká Knížová, Habtamu Marew, Kateřina Podolská, Rumiana Bojilova
Institute of Atmospheric Physics, Czech Academy of Sciences; Institute of Earth Physics and Space Science (EPSS), Sopron, Hungary; Institute of Earth Physics and Space Science (EPSS), Sopron, Hungary; Leibniz Institute of Atmospheric Physics at the University of Rostock, Kuehlungsborn, Germany; STCE – Royal Meteorological Institute, Ukkel, Belgium; Institute of Atmospheric Physics, Czech Academy of Sciences; Institute of Atmospheric Physics, Czech Academy of Sciences; Institute of Atmospheric Physics, Czech Academy of Sciences; Institute of Atmospheric Physics, Czech Academy of Sciences; Institute of Atmospheric Physics, Czech Academy of Sciences; Institute of Atmospheric Physics, Czech Academy of Sciences; National Institute of Geophysics, Geodesy and Geography – Bulgarian Academy of Sciences
Abstract: Our contribution presents a deep and comprehensive multi-instrumental analysis of two distinct ionospheric storms occurring in March and April 2023 in the middle-latitudinal European region utilizing ionospheric vertical sounding at five European stations: Juliusruh, Dourbes, Pruhonice, Sopron, and a reference station, San Vito. Additionally, we employ Digisonde Drift Measurement, Continuous Doppler Sounding System, local geomagnetic measurements, and optical observations. We concentrate on the F2 and F1 region parameters and shape of the electron density profile. During the March event, a pre-storm enhancement was observed, characterized by an increase in electron density up to approximately 20% at northern stations, with minimal effect observed at San Vito.
We present a novel detailed temporal and spatial description of a so-called G-condition. It was observed not only in the morning hours in the period of the increased geomagnetic activity during (and shortly after) the main phase of the storm, but also during low to moderate geomagnetic activity with Kp between 1 and 3+. Further, an alteration in the shape of the electron density profile, notably captured by the parameter B0 was observed. A substantial increase in B0, by several hundred percent, was noted during both events on the day of the geomagnetic disturbance and importantly also on the subsequent day with low-to-moderate geomagnetic activity.
During both storms, the critical frequency foF1 decreased at all stations including San Vito. Changes in electron density in the F1 region indicate plasma outflow during morning hours. Distinct and persistent oblique reflections from the auroral oval were observed on the ionograms for several hours during both events and these observations were in agreement with optical observations of auroral activity and concurrent rapid geomagnetic changes at collocated stations.
For the first time, we present a unique and convincing excellent agreement between the Continuous Doppler Sounding System and Digisonde Drift Measurement. The results reveal vertical movement of plasma up to ±80 m/s. Analysis of observed vertical plasma drifts and horizontal component H of magnetic field in Czechia and Belgium suggest that vertical motion of the F-region plasma is caused by ExB plasma drift.
Author(s): D.ario Sabbagh, Loredana Perrone
Istituto Nazionale di Geofisica e Vulcanologia; Istituto Nazionale di Geofisica e Vulcanologia
Abstract: In this study we investigate the variations of the hourly observations at the Ionospheric Observatory of Rome (41.82° N, 12.51° E) during the last deep solar minimum 2018-2020 and next to the approaching solar maximum 2021-2023 of solar activity. The values of the critical frequency of the F2 layer (foF2) manually scaled from the ionograms recorded by the AIS-INGV ionosonde, and the vertical Total Electron Content (vTEC) acquired by the co-located GNSS receiver are analysed to detect ionospheric anomalies.
Each hourly deviation of foF2 greater than ±15% with respect to a background level defined by 27-day running median values is here considered, while the Interquartile Range (IQR) method applied to the same running windows is used to define vTEC anomalous values. Short-Persistence (SP) and Long-Persistent (LP) anomalies are then defined for both the quantities, according to their sign and duration (i.e., 2-3 hours or ≥4 hours, respectively). The dependence of these strong variations on geomagnetic activity has been accurately investigated, along with their occurrence during daytime/night-time hours and the different seasons.
A detailed analysis of specific cases, as the two moderate geomagnetic storms occurred in February 2022, that determined the loss of 38 STARLINK satellites, has been carried out.
Author(s): Enkelejda Qamili, Roberta Forte, Nicola Comparetti, Alessandro Maltese, Antonio De la Fuente, Anja Stromme
SERCO for European Space Agency (ESA-ESRIN); SERCO for European Space Agency (ESA-ESRIN); SERCO for European Space Agency (ESA-ESRIN); SERCO for European Space Agency (ESA-ESRIN); European Space Agency (ESA-ESRIN); European Space Agency (ESA-ESRIN)
Abstract: After 10 years in Space, Swarm ESA’s Earth Explorer mission continues to be in excellent shape and continues to contribute to a wide range of scientific studies, from the core of our planet, via the mantle and the lithosphere, to the ionosphere and its interactions with Solar wind.
Its highly accurate observations of electromagnetic and atmospheric parameters of the near-Earth space environment, and the peculiar mission constellation design, make Swarm eligible for developing novel Space Weather products and applications.
In November 2023 a “Fast” processing chain has been transferred into operations, providing Swarm L1B products (orbit, attitude, magnetic field and plasma measurements) with a minimum delay with respect to the acquisition. And, since July 2024, also new FAC (Field Aligned Current) L2 products are being generated with the “Fast” chain and are now available on Swarm dissemination server as well.
These Fast data products add significant value in monitoring present Space Weather phenomena and help modelling and nowcasting the evolution of several geomagnetic and ionospheric events.
This work presents the set-up of the Swarm “Fast” data processing chain, current status and plans for future improvements and applications.
Author(s): Artem Reznychenko, Andriy Zalizovski, Oleksandr Koloskov, Volodymyr Lisachenko, Yuri Yampolski, Sergei Kashcheyev, Iwona Stanislawska, Mariusz Pożoga, Anton Kashcheyev, Vadym Paznukhov
(1) Institute of Radio Astronomy of NAS of Ukraine, Kharkiv, Ukraine / (2) Space Research Centre of Polish Academy of Sciences, Poland; (1) Institute of Radio Astronomy of NAS of Ukraine, Kharkiv, Ukraine / (2) Space Research Centre of Polish Academy of Sciences, Poland / (3) National Antarctic Scientific Center of Ukraine, Kyiv, Ukraine; (1) Institute of Radio Astronomy of NAS of Ukraine, Kharkiv, Ukraine / (3) National Antarctic Scientific Center of Ukraine, Kyiv, Ukraine / (4) University of New Brunswick, NB, Fredericton, Canada; (1) Institute of Radio Astronomy of NAS of Ukraine, Kharkiv, Ukraine; (1) Institute of Radio Astronomy of NAS of Ukraine, Kharkiv, Ukraine; (1) Institute of Radio Astronomy of NAS of Ukraine, Kharkiv, Ukraine; (2) Space Research Centre of Polish Academy of Sciences, Poland; (2) Space Research Centre of Polish Academy of Sciences, Poland; (4) University of New Brunswick, NB, Fredericton, Canada; (5) Boston College, Institute for Scientific Research, Chestnut Hill, MA, USA
Abstract: The network of spatially separated remote-controlled Doppler HF receiving sites, developed by the Radio Astronomy Institute of the National Academy of Sciences of Ukraine enables the study of HF radio signals propagation features on radio lines of different lengths and latitudes. Long-term, continuous measurements allow investigating various ionospheric processes and impact of atmospheric and cosmic factors on these processes. Such research contributes to the development of the engineering models that link the parameters of signal propagation on different latitudinal regions with ionospheric and space weather conditions. The network includes both high latitudes receiving points located in the Arctic (Tromso and Longyearbyen, Norway) and Antarctica (at the Ukrainian Antarctic Station Akademik Vernadsky) and mid-latitudes sites situated in Ukraine. Unfortunately, several monitoring sites of the HF receiver network in Ukraine were destroyed by the invaders. Therefore, the restoration and upgrading of the network with new observation points are crucial tasks. In August 2022 a new HF receiving site was created at LOFAR PL610 observatory operated by the Space Research Centre of Polish Academy of Sciences in Borowiec, Poland. Since August 2022, receivers in Borowiec register the HF signals from the CHU time service station (Canada) and send data to the database. This study presents preliminary results of operation of the new receiving point and continuous functioning of the whole receiving network after modernizations.
Two years of measurements have enabled us to track seasonal variations in the signal propagation conditions on the CHU-Borowiec radio path. Notable features were observed. Among them is the appearance of sky wave propagation when the rising-up solar terminator crosses the receiving point but almost the whole direct radio path is still shadowed yet.
In addition to long-term observations, the network is also used for case study of some events. This year we participated in measuring the ionospheric effects of the solar eclipse on April 8, 2024. During the eclipse, the signals from the CHU radio station were monitored on several probe radio paths, including, the reception positions at Fredericton, Canada, and Boston USA. The Doppler frequency shifts (DFS) of signals at all receiving points demonstrate a reaction to the intersection of the lunar full and partial shadow with radio paths. We carried out a simulation of the impact of changes in integral illumination over the radio paths on DFS variations. It shows a good agreement between the model and experimental DFS curves. These findings might be valuable for updating the ionospheric models as well as for better understanding the mechanisms of manifestation of various ionospheric and space weather events in the parameters of HF signals.
Author(s): Kseniia Golubenko, Eugene Rozanov, Mélanie Baroni, Timofei Sukhodolov, Ilya Usoskin
University of Oulu
Abstract: We introduce a chemistry-climate model (CCM) SOCOL-AERv2-BE, specifically designed to track cosmogenic isotopes of beryllium in the atmosphere. The model is based on the original code of CCM SOCOL (SOlar Climate Ozone Links) and includes the general circulation model (GCM) MA-ECHAM5 for the low and middle atmosphere, an updated version of the atmospheric chemistry-transport model MEZON, and the aerosol module AER. SOCOL can operate with various levels of detail in terms of horizontal resolution (spectral truncation T31 or T42) and vertical layers (39 or 90) and has been specifically tuned to model the transport of beryllium. This includes the interactive deposition scheme which encompasses both wet and dry depositions. The modelled concentrations of 7Be and 10Be in near-ground air have been systematically compared with the measured values at four nearly antipodal high-latitude locations. The model results agree with the measurements within the uncertainties, suggesting that the model reasonably well reproduces the processes of production, decay (for 7Be), and lateral deposition of the isotopes. Furthermore, the model successfully captured the temporal variability of Be concentrations on both annual and sub-annual scales, demonstrating an adequate reproduction of the dominant annual cycle observed in the Northern Hemisphere. For practical applications, we developed a straightforward parameterization of the full-model outcomes, which provides a quick robust estimate of the 10Be concentrations in near-surface air in polar regions and agrees within 20% with the full model. This enables rapid yet robust estimation of near-ground 10Be concentrations, based only on computed production rates in 18 or 96 production zones, without the need for full transport model computations. Such a practical approach can be directly used in studies of solar and geomagnetic variability using cosmogenic isotopes.
Author(s): Eric Sutton
University of Colorado at Boulder
Abstract: Interactions between resident space objects in low-Earth orbit (LEO, i.e., the region below ~1,000 km altitude) and the ambient atmospheric environment cause significant orbital perturbations. While LEO is a most desirable orbital regime from the standpoint of debris disposal, the uncertainty of an object’s orbital trajectory is often a limiting factor in the accuracy of conjunction assessments used to determine when and if a collision-avoidance maneuver is needed. At the same time, the increasing population of LEO over the last 5 years has compounded the overall risk of collisions. By combining tracking data from recently launched small satellites, often in the form of high-rate GNSS observables or quantities derived thereof, with attitude and satellite geometry information, the thermosphere can be observed with unprecedented coverage. The necessary information is available, in various forms, from several mega constellations, including Starlink, Spire, and others. This talk will outline the progress, challenges, and limitations of working with multiple commercial datasets as well as the promise of scientifically instrumented, targeted missions.