Magnetic field observations have a long history of advancing our understanding of ionospheric current flow, even before we launched space missions. Earlier magnetic field missions were single satellites that provided new insights into ionospheric current flow. Swarm is the first constellation focused on measuring magnetic fields from LEO. In this talk, we will focus on the value of knowing the magnetic field variation and discuss challenges, advances, and future opportunities.
One scientist's signal is another scientist's noise, and therefore working with magnetic perturbation leads to the collaboration of scientists from solid Earth to the magnetosphere. Opportunities can be challenges since magnetic observations include the signal from many sources which can be from far away or close by, making the interpretation of magnetic signals often difficult. In ionosphere-thermosphere numerical modeling, magnetic perturbations are not a standard diagnostic even though a wealth of data exists. While ionospheric data is used for data assimilation, magnetic data so far is not. A huge advantage of the Swarm satellite configuration is that it can unambiguously identify ionospheric current flow when the satellites are close. A similar concept is used by NASA Electrojet Zeeman Imaging Explorer (EZIE), a CubeSat mission scheduled for launch in spring 2025. In addition, EZIE is unique as it will measure the magnetic field around 80 km remotely via Zeeman splitting, to shed light on the substorm current flow and the equatorial electrojet.
In this presentation, we will describe the value of studying the ionospheric current to gain insights into the ionosphere-thermosphere system. We will show examples from high to low latitudes illustrating how magnetic perturbation especially in constellations and combined ground and space based data can advance our understanding of the MIT system. We conclude with thoughts about future observations.
How to cite: Maute, A., Yee, J.-H., Gjerloev, J., Alken, P., and Merkin, S.: Missions and efforts using magnetic field observations to advance our knowledge of the coupled magnetosphere-ionosphere-thermosphere (MIT) system, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6857, https://doi.org/10.5194/egusphere-egu25-6857, 2025.
In this study, we analyze electron density measurements from the Low-Earth Orbiting (LEO) satellite constellations Swarm and GRACE-FO to examine the effects of the May-2024 geomagnetic storm on the equatorial and low-latitude ionosphere. Results show that the equatorial ionization anomaly (EIA) was particularly enhanced on the dayside and depleted on the nightside. Notably, an intensification of the EIA was observed during early morning hours (at ~05/07 LTs) by the GRACE-FO and Swarm A satellites. The observed EIA modifications can be attributed to the strong influence of the electric fields and thermospheric winds. Comparisons with CHAMP and GRACE observations during the Halloween storm indicate an increase of a similar order of magnitude in the EIA’s crest-to-trough ratio (CTR) and L-value around similar local times and longitudes, emphasizing the May-2024 storm as one of the strongest geomagnetic storms in the space age. Additionally, strong equatorial plasma depletion (EPD) activity was noted, including EPDs detected during early morning hours at ~05 LT (~07 LT) by GRACE-FO (Swarm A). These EPDs reached very high apex altitudes of ~5000 km during pre-midnight and ~3400 km at early morning hours during 11-12 May, in contrast to ~1000 km during pre-storm conditions. The lower apex altitude of the early morning EPDs than of the pre-midnight EPDs suggests that these EPDs are generated after midnight and they are not remnants from the previous evening. This suggestion is also supported by ground-based ionosonde observations in Southeast Asia, combined with satellite data, which reveal an elevation of the ionosphere after midnight, supporting the Rayleigh-Taylor instability mechanism crucial for the EPD growth.
How to cite: Das, S. K., Stolle, C., Yamazaki, Y., Rodríguez-Zuluaga, J., Wan, X., Kervalishvili, G., Rauberg, J., Zhong, J., and Perwitasari, S.: On the low-latitude ionospheric responses to the May-2024 geomagnetic storm observed by LEO satellites, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3337, https://doi.org/10.5194/egusphere-egu25-3337, 2025.
Geomagnetic storms significantly impact the morphology and dynamics of the Equatorial Ionization Anomaly (EIA). The geomagnetic storm of May 10, 2024, also known as the “Mother’s Day Storm”, was the most intense geomagnetic storm in the last two solar cycles. Given its severity, understanding the storm's impact on the ionosphere is crucial. This study investigates the variations of the low-latitude ionosphere during the Mother's Day Storm, utilizing observations from ESA’s Swarm satellites, as well as total electron density (TEC) estimates from the ground.
Data from the Langmuir Probes, the Electric Field Instrument (EFI), and TEC derived from GPS receivers onboard The Swarm satellites were used to analyze the F-region ionosphere. Additionally, ground-based TEC maps from the Madrigal database were employed to examine the altitudinal evolution of the EIA structure.
Results demonstrate a significant enhancement of the double-peak electron density structure of the EIA during the main phase of the storm (starting around 17 UT on May 10), with evidence of the super fountain effect. The EIA crests reached altitudes above the Swarm B satellite orbit (510 km), extending to approximately 40 degrees north and south of the equator. In contrast, the generation of the EIA was suppressed during the storm's recovery phase. These behaviors are interpreted in the context of storm-induced electric fields.
How to cite: Mohandesi, A., Knudsen, D. J., Skone, S., and Ghadjari, H.: Investigating Low-latitude Ionospheric Variations During the 2024 "Mother's Day Storm": Combined Swarm and Ground-Based Observations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14373, https://doi.org/10.5194/egusphere-egu25-14373, 2025.
The response of the ionosphere-thermosphere system in Europe during the severe geomagnetic storm of May 2024 was investigated. Between May 7 and 11, multiple X-class solar flares and at least five Earth-directed coronal mass ejections (CMEs) were observed. The initial CME impacted Earth at 12:30 PM UTC on May 10, triggering a geomagnetic enhancement and inducing a negative ionospheric storm over mid-latitude European stations, leading to data gaps on May 11 due to the "G condition" (wherein the electron density at the F2 layer maximum equals or falls below that of the F1 layer maximum).
Thermospheric parameters analyzed using the THERION method revealed a 60% increase in neutral [O] density at 300 km altitude and elevated thermospheric temperatures(~50% increase), while column [O] concentrations showed a ~30% decrease. Enhanced equatorward winds, peaking at 79 m/s, were observed between May 10 and 13. Comparative analysis with other longitudinal sectors confirmed significant regional responses, emphasizing the dynamic behavior of the coupled ionosphere-thermosphere system during severe geomagnetic events.
How to cite: Perrone, L., Mikhaylov, A., Sabbagh, D., and Bagiacchi, P.: Ionosphere-Thermosphere System Response During the May 2024 Geomagnetic Storm, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4988, https://doi.org/10.5194/egusphere-egu25-4988, 2025.
A peculiar compressional Pc3 magnetic pulsation was observed by the Swarm satellites on the dayside which may have been caused by the Lamb wave generated at the Tonga undersea volcanic eruption on January 15, 2022. The difference between this and other usual compressional Pc3 pulsations observed at low and mid-latitudes is its spectral structure. The power spectral density (PSD) usually peaks at the periods between 20 and 30 sec, but in this event observed on the dayside orbit around the time when the Lamb wave passed under the Swarm orbit, the PSD peaks below 20 sec and is small in the periods longer than 20 sec. It is shown that this is a very rare case, although not the only one, during the period examined, i.e., from December 2013 to April 2022. The PSD has many sharp spectral peaks, but they don't have usual harmonic structure, and the frequencies of the peaks are nearly common with those of other similar events. The Pc3s observed at low-latitude (L<3 Re) ground magnetic stations simultaneously with the satellites show a very good correspondence of PSD peaks with those of the Swarm satellites although those of high-latitude station do not. The solar wind on January 15, 2022 was disturbed and high speed, so the possibility that the solar wind was the cause of the Pc3 cannot be completely excluded. However, the coincidence of the Pc3 appearance with the Lamb wave arrival, its peculiar spectral structure, and a comparison with ground magnetic observations suggest that this phenomenon is likely to be related to the Lamb wave arrival. A plasmaspheric cavity resonance excited by a magneto-sonic wave injected from the ionosphere via ionospheric dynamo could be a possible mechanism. This is probably the first report on a Pc3 magnetic pulsation possibly caused by lower atmospheric disturbance.
How to cite: Iyemori, T., Yokoyama, Y., and Aoyama, T.: A Pc3 magnetic pulsation possibly associated with the Lamb wave generated by the 2022 Tonga undersea volcanic eruption, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7665, https://doi.org/10.5194/egusphere-egu25-7665, 2025.
The Swarm data base is well-suited to address a number of topics of serious interest in space weather science and monitoring as for instance: spatial and temporal characteristics of ionospheric electron density, improving topside approaches in ionospheric models for monitoring and forecasting the dynamics of the geo-plasma environment. In this study, we developed a neural network-based electron density model using the electron density measured by Langmuir probes on the Swarm A and C satellites. Data from the years 2014 till 2021 has been used for this study, where the satellites have an approximate altitude range of 470-430 km. The model’s capability of showing large and small-scale features of the ionosphere was tested and the results show that the model is capable of showing the crest formations on both sides of the magnetic equator, as well as seasonal and diurnal variations. Furthermore, using the neural network-based model predictions, the nighttime winter anomaly (NWA) feature was investigated. The NWA is a small-scale feature that can be observed during low solar activity conditions at nighttime in the Northern Hemisphere at the American sector and in the Southern Hemisphere at the Asian sector. Such electron density models at specific height region can be used for three-dimensional ionosphere model validation as well as for the development of improved ionosphere models. Again, accurate modelling and monitoring of ionospheric electron density at certain height region can help prediction of space weather impact.
How to cite: Adolfs, M. and Hoque, M. M.: Electron density modelling at Swarm height using Neural Networks for space weather monitoring, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13355, https://doi.org/10.5194/egusphere-egu25-13355, 2025.
An intense surge in equatorial electron temperature (Te) at sunrise, known as the morning Te overshoot, has been one of the most widely studied ionospheric features since its discovery in the early Space Age. Despite extensive research, its behavior during geomagnetic storms remains poorly understood. Using global electron temperature observations by the CHAllenging Minisatellite Payload (CHAMP) mission in 2002-2010, we develop a neural network Te model, which helped us uncover a two-stage response of the morning Te overshoot to geomagnetic activity. During the storm’s main phase, electron temperatures in the overshoot region exhibit a pronounced enhancement, which is followed by a dramatic depletion exceeding 1000 K and the disappearance of the overshoot during the recovery phase. This two-phase evolution corresponds to the initial impact of a westward prompt penetration electric field (PPEF), which reduces electron densities therefore allowing for a more efficient energy exchange between the newly ionized particles at sunrise and lower energy (depleted) ambient plasma. The initial PPEF influence is overtaken by the eastward disturbance dynamo field later in the storm, which flips the ExB drift from downward to upward and lifts more electrons into the F-region. Increased electron densities enhance the cooling rates leading to the disappearance of the overshoot in the recovery phase of the storms. Our findings shed new light on the dynamics of the morning electron temperature overshoot and highlight the capability of digital twin models to uncover previously unrecognized physical phenomena in the near-Earth space environment. Additionally, we discuss the applications of the developed model for various ionospheric applications, including the calibration of electron temperatures from Swarm Langmuir Probes.
How to cite: Smirnov, A., Shprits, Y., Lühr, H., Pignalberi, A., Kronberg, E., Prol, F., and Xiong, C.: Extreme two-phase change of the ionospheric electron temperature overshoot during geomagnetic storms uncovered by neural networks, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19863, https://doi.org/10.5194/egusphere-egu25-19863, 2025.
Geomagnetic field and ionospheric environment monitoring is presently achieved with huge success by the three satellites of the Swarm Earth Explorer ESA constellation launched in November 2013. Maintaining and improving observations beyond the lifetime of Swarm is critical for both science investigations and advanced applications. NanoMagSat aims at fulfilling this goal. This much cheaper mission is currently in Phase B within the context of the ESA Scout program. It will deploy and operate a new Low-Earth orbiting constellation of three identical 16U nanosatellites, using two inclined (~ 60°) and one polar orbits at an initial altitude of 545 km, to complement and take over the Swarm mission. The mission is planned to start deploying end of 2027, for a minimum of three years of full constellation operation between 2028 and 2031.
This constellation is designed to cover all local times (LT) at all latitudes, with special emphasis on latitudes between 60°N and 60°S, where all LT will be visited within about a month, much faster than is currently achieved by the Swarm constellation. Each satellite will carry an advanced Miniaturized Absolute scalar and self-calibrated vector Magnetometer (MAM) with star trackers (STR) collocated on an ultra-stable optical bench at the tip of a deployable boom, a new compact High Frequency Magnetometer (HFM) (at mid-boom), a multi-Needle Langmuir Probe (m-NLP) and dual frequency GNSS receivers (all on the satellite body). This payload suite will acquire high-precision/resolution oriented absolute vector magnetic data at 1 Hz, very low noise scalar and vector magnetic field data at 2 kHz, electron density data at 2 kHz, and electron temperature data at 1 Hz. GNSS receivers will also allow top-side TEC and ionospheric radio-occultation profiles to be recovered.
In this presentation, the main science goals of the mission will first be introduced and the rationale for the choice of the payload and constellation design next explained. The various data products currently planned to be produced will also be described. Special emphasis will be put on the innovative aspects of the mission with respect to Swarm and other previous missions. Finally, the benefit of relying on such nanosatellite constellations for maintaining long-term observations of the magnetic field and ionospheric environment, to complement ground-based observations will also be discussed.
How to cite: Hulot, G., Coïsson, P., Léger, J.-M., Clausen, L. B. N., Jørgensen, J. L., van den Ijssel, J., Chauvet, L., Jager, T., Deconinck, F., Nieto, P., Cipriani, F., Pastena, M., and Lejault, J.-P.: The Upcoming ESA Scout NanoMagSat Mission, a Nanosatellite Constellation to Further Improve Geomagnetic Field and Ionospheric Environment Monitoring and Modeling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9287, https://doi.org/10.5194/egusphere-egu25-9287, 2025.
Modern geomagnetic field models can successfully represent many details of the observed large-scale field and its slow time changes. However, the obtained model uncertainty is often underestimated, which limits our ability to evaluate the reliability of signals recovered in the field models. The increasing amount of globally distributed, high-quality magnetic data observed by low-Earth orbit satellites, such as Swarm, MSS-1 and the planned NanoMagSat mission, present an opportunity to improve the model uncertainty by providing important statistical information on the expected errors of the input magnetic data used in field modelling.
During the field model estimation, data errors are usually assumed to be uncorrelated in time and independent of position. However, limitations in the parameterization of the models regarding magnetospheric and ionospheric sources lead to residuals between model predictions and magnetic observations that are not only larger than the expected measurement noise but are also correlated and varying with position. Not adequately describing these correlations during the model estimation leads to unrealistic model uncertainties, which hinders, for example, their use in applications such as assimilation into numerical Geodynamo simulations.
Here, the statistics of vector residuals between magnetic observations from the Swarm satellites and the CHAOS-7 geomagnetic field model predictions are studied by computing sample means and covariances for the field components as a function of time and magnetic coordinates. This analysis reveals significant covariances, particularly at mid-to-high latitudes. The sample covariances are used to construct non-diagonal data error covariance matrices, which can be used in field modelling.
Finally, test field models built using the non-diagonal data error covariances matrices within the CHAOS modelling framework are discussed, illustrating the effect of correlated data errors on the recovered fields and the associated model uncertainties.
How to cite: Kloss, C.: Accounting for correlated errors in Swarm magnetic data within the CHAOS field modelling framework, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11188, https://doi.org/10.5194/egusphere-egu25-11188, 2025.
Measurements from geomagnetic satellites continue to underpin advances in geomagnetic field models that describe Earth’s internally generated magnetic field. Here we present a new field model: MSCM that integrates vector and scalar data from the Swarm, CSES, and MSS-1 satellites. The model spans 2014.0 to 2024.5, incorporating the core, lithospheric, and magnetospheric fields, showing similar characteristics to other published models. For the first time, we demonstrate that incorporating CSES vector data successfully produces a geomagnetic field model, albeit one in which the radial and azimuthal CSES vector components are Huber downweighted. We further show that data from MSS-1 can be used to construct a fully time-dependent geomagnetic field model. MSCM identifies new behaviour of the South Atlantic Anomaly, the broad region of low magnetic field intensity over the southern Atlantic. This prominent feature appears split into a western and eastern part, each with its own intensity minimum. Since 2015, the principal western minimum has undergone only modest intensity decreases of 290 nT and westward motion of 20km/yr, while the recently-formed eastern minimum has shown an intensity drop 2-3 times greater of 730nT with no apparent motion.
How to cite: Gao, Y., Wang, Z., Livermore, P., Rogers, H., and Liu, C.: MSCM: A geomagnetic Model derived from Swarm, CSES and MSS-1 satellite data and the evolution of the South Atlantic Anomaly, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12183, https://doi.org/10.5194/egusphere-egu25-12183, 2025.
KASI has been developing LEO satellite observation missions to study the Earth's ionosphere and upper atmosphere. These missions include SNIPE (Small scale magNetospheric and Ionospheric Plasma Experiment), SNIPE-2 (Small scale magNetospheric and Ionospheric Plasma Experiment-2), ROKITS (Republic Of Korea Imaging Test System), and ATHENA (Aurora THErmosphere ioNosphere for spAceweather). The successful launch of the SNIPE (Small scale magNetospheric and Ionospheric Plasma Experiment) mission in May 2023, featuring a formation flight of three nanosatellites, enables simultaneous observation of the spatio-temporal changes in plasma microstructures in the near-Earth space. It is still operational as of January 2025 and has provided high-quality observations of ionospheric plasma changes, particularly during the intense geomagnetic storms of May and October 2024. Based on this SNIPE, development of SNIPE-2, which will conduct stable near-Earth space exploration with six CubeSats, has also begun. Looking ahead, KASI’s upcoming mission, ROKITS (Republic Of Korea Imaging Test System), is scheduled for launch in 2025 to observe the Earth’s upper atmosphere with a wide-field aurora/airglow imager in visible wavelength (OI 557.7 nm and OI 630.0 nm). This imager will operate in a noon-midnight sun-synchronous orbit at an altitude of 600 km. The primary scientific goal of ROKITS is to define the boundary of the auroral oval and analyze various auroral shapes and the evolution of auroral features. Additionally, KASI is initiating an ambitious mission ATHENA (Aurora and Thermosphere: Energetics, Neutrals, and Atmosphere). ATHENA aims to advance our understanding of space weather forced from above and below using the observations by two threshold payloads: optical imagers operating in visual/infrared (KASI/ROKITS_IR) and far-ultraviolet (JHUAPL/GUVI+) wavelengths. ATHENA will fly these instruments in a near-polar, sun-synchronous orbit at about 640km. The key space weather parameters from the mission include auroral boundary and external energy input, atmospheric gravity waves, and vertical profiles of main atmospheric constituents. This presentation outlines the current and future LEO satellite exploration efforts of Korea’s Earth’s ionosphere and Thermosphere.
How to cite: Kwak, Y.-S., Lee, J., Lee, W. K., Kil, H., and Park, J.: Korea’s LEO Satellite Explorations of the Earth’s Ionosphere and Thermosphere, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20929, https://doi.org/10.5194/egusphere-egu25-20929, 2025.
The VirES service[1] has been developed to make Swarm products accessible to programmers and non-programmers alike. Web services provide robust access to both data and models, which are coupled to a graphical interface for easy exploration and visualisation, as well as Python tooling to support community-developed tools and processing options. VirES is also integrated with other data systems through adoption of the Heliophysics API (HAPI)[2].
The web client GUI provides both 3D visualisation and customisable 2D plotting, allowing data exploration without any programming required. On the other hand, ready-to-run Jupyter notebooks[3] provide the more intrepid explorer the opportunity to generate more bespoke analysis and visualisation. The notebooks are backed by a JupyterHub furnished with domain-relevant Python packages, which together lower the barrier to entry to programming. Both the web client and notebooks are interlinked with the Swarm handbook[4] which provides more detailed documentation of products.
While the service was originally developed to serve Swarm products, we also provide access to ground magnetic observatory data derived from INTERMAGNET, as well as Swarm "multimission" products derived from other spacecraft as part of Swarm projects. We are actively looking into ways in which the service and associated software can support related missions, including the Macau Science Satellites and NanoMagSat.
VirES is developed for ESA by EOX IT Services[5], in close collaboration with researchers across the Swarm Data, Innovation, and Science Cluster (DISC). We aim to produce a sustainable ecosystem of tools and services, which together support accessibility, interoperability, open science, and cloud-based processing. All services are available freely to all, and the software is developed openly on GitHub[6,7].
[1] https://vires.services
[2] https://hapi-server.org
[3] https://notebooks.vires.services
[4] https://swarmhandbook.earth.esa.int
[5] https://eox.at
[6] https://github.com/ESA-VirES
[7] https://github.com/Swarm-DISC
How to cite: Pačes, M. and Smith, A.: ESA's VirES service for accessing and analysing data from Swarm and beyond, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20825, https://doi.org/10.5194/egusphere-egu25-20825, 2025.
Whistlers are generated by the electromagnetic signal from lightning discharges leaking into the
ionosphere and magnetosphere. They propagate upward through the ionosphere, where they can be
detected by satellites. The dispersion of whistler signal during propagation has been empirically
described by Eckersley [1935] by the following law: T = D / √ f , where T is the group delay of the
wave packet, f is its frequency and D is called the dispersion of the whistler.
We focus on events detected during burst-mode campaigns of the Absolute Scalar Magnetometer
(ASM) of the Swarm satellites at orbital altitudes ~475 km (Alpha) and ~510 km (Bravo). Since
the bandwidth of interest of this instrument lies between 10 Hz and 125 Hz, the whistlers detected
are in the Extremely Low Frequency (ELF). In this band, whistler propagation differs from the
more commonly studied Very Low Frequency (VLF) whistlers and presents a unique set of
characteristics. In particular, in the equatorial region (±5° of magnetic inclination), Eckersley’s
empirical dispersion description seems to break down.
To investigate such propagation oddity, we model the ELF whistler propagation of equatorial
whistler with a ray tracing technique using the International Reference Ionosphere 2016 (IRI) and
a local dipolar magnetic field approximation derived from the IGRF-13 as background models.
Ray tracing provides an estimate of the propagation path and the group delay of the whistler. Since
ray tracing is an application of geometric optics, it has inherent limitations for large wavelength
that are characterized in the context of ELF whistler simulation.
Ray tracing allows us to successfully model ELF whistler dispersion as detected by Swarm ASM.
This is tested on both whistler following Eckersley’s law and equatorial whistlers. For the latter
case, the simulated group delay is shown to have two main contributions: the first is related to the
expected wave dispersion and the second to the special propagation geometry of these signals.
Indeed, the various frequency components of equatorial whistlers have ray paths that differs
widely, impacting the length traveled by the rays and thus their group delay. This explains well the
group delay of ELF equatorial seen in Swarm ASM data.
How to cite: Jenner, M., Coisson, P., Hulot, G., Deborde, R., and Chauvet, L.: Ray Tracing of the Equatorial Extremely Low Frequency Whistlers Detected by the Swarm Mission, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7098, https://doi.org/10.5194/egusphere-egu25-7098, 2025.
Radio waves are subject to a variety of propagation effects when traversing through the ionosphere. These effects depend on the radio wave frequency as well as on the ionospheric conditions that determine the spatial distribution of plasma density along a given ray path. Ionospheric propagation effects can be determined at various orders of approximation of the Appleton-Hartree equation for the refractive index. These propagation effects vary according to the variability of the ionosphere, which is driven by complex combinations between factors such as solar and magnetic activities,
This contribution discusses the variability of ionospheric conditions in relation to propagation effects. The ionospheric variability was estimated by using a diverse set of information: ionospheric and magnetic models, in-situ and ground observations.
Within a timespan of a solar cycle, from November 2013 to November 2024, the European Space Agency's SWARM constellation has enabled unprecedented studies of Earth's Ionosphere and Magnetosphere through the provision of continuous, high temporal and spatial measurements of electron density and magnetic field parameters. In this work electron density and magnetic field in-situ SWARM observations are compared with the IRI model (Bilitza et al., 2017), the IGRF model (Thebault et al., 2015), and with ground observations. Ground-based observations, including electron density parameters recorded by GIRO ionosondes and magnetic field strength recorded by selected magnetometers, collected at geographically diverse locations were compared with SWARM’s in-situ measurements at different magnetic latitudes/longitudes, and under various ionospheric conditions over an entire solar cycle.
This analysis covered an entire solar cycle period and included an assessment of both active and quiet conditions (e.g., through the use of indices such as Kp).
Initial comparisons between SWARM’s electron density in-situ measurements, GIRO ionosonde observations and the IRI model, as well as between SWARM’s magnetic field strength measurements, ground-based magnetometer data and the IGRF model, seem to suggest a higher ionospheric variability across different latitudes/longitudes, and geomagnetic conditions. The results indicate how a dataset such as offered by SWARM and other similar missions, in synergy with ground-based observations, can form a useful framework to improve the understanding of the ionospheric variability and the corresponding propagation effects.
[1] Bilitza, D., Shubin, V., Truhlik, V., Richards, P., Reinisch, B., & Huang, X. (2017). International Reference Ionosphere 2016: From ionospheric climate to real-time weather predictions. Space Weather, 15(2), 418–429.
[2] Thebault, E., Finlay, C. C., Beggan, C. D., Alken, P., Aubert, J., Barrois, O., … & Zhou, B. (2015). International Geomagnetic Reference Field: The 12th generation. Earth, Planets and Space, 67, 79.
How to cite: Lu, T., Forte, B., Kinsler, P., and Van den IJssel, J.: A study of ionospheric variability through SWARM and ground-based observations to inform on the variability of radio propagation effects., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12507, https://doi.org/10.5194/egusphere-egu25-12507, 2025.
The mass density scale height in the upper atmosphere gives the vertical distance over which the neutral mass density decreases by a factor of e (the base of natural logarithms). The change in scale height may depend on changes in neutral temperature and/or composition. This study uses simultaneous measurements of neutral mass density from coplanar low-Earth-orbit satellites to derive the neutral mass density scale height and analyses the variations of the scale height during quiet time and geomagnetic storms. The coplanar events are found in the satellite missions from 2014 to 2023, including Swarm, GRACE, and GRACE-FO.
Our study shows several interesting findings. During geomagnetic storms, the scale heights are increased significantly (by up to 15 km), probably mainly due to increased upper thermospheric temperature. The increase in scale height depends on latitude, local time, and season. In the summer hemisphere and on the dayside, the upper thermospheric temperature (or exospheric temperature) can be estimated by assuming the dominant composition of the neutrals is the atomic oxygen at the LEO satellite altitudes. Additionally, during quiet time, the semi-diurnal tides are revealed in neutral mass density scale height. The results provide strong evidence of the propagation of the atmospheric tides from below to the topside ionosphere-thermosphere, which affects the upper thermospheric temperature and/or composition. This is also a new way for atmospheric tidal diagnostics based on LEO satellite measurements.
How to cite: Vanhamäki, H., Cai, L., Aikio, A., Pedersen, M., and Myllymaa, M.: Variations of upper thermospheric scale height based on neutral mass density measurements from coplanar low-Earth-orbit satellites, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15392, https://doi.org/10.5194/egusphere-egu25-15392, 2025.
The China-Seismo-Electromagnetic Satellite (CSES) mission delivers in-situ measurements of the plasma, electromagnetic fields, and charged particles in the topside ionosphere. Each CSES spacecraft carries several different scientific payloads delivering a wealth of information about the ionospheric plasma dynamics and properties and the energetic particles precipitating in the ionosphere or coming from outside the Earth environment. Here we present CSESpy, a python package designed to provide easy access to CSES Level 2 data products, with the aim to ease the pathway for scientists to carry out the analysis of CSES data, increase opportunities for collaboration and boost joint research efforts.Beyond simply being an interface to the CSES database, CSESpy aims at providing higher-level analysis and visualization tools, as well as tools for combining concurrent measurements from different data products, so as to allow multi-payload and even multi-satellite studies in a unified framework. CSESpy is designed to be highly flexible, as such it can be extended to interface with datasets from other sources and can be embedded in wider software ecosystems for the analysis of space physics data. Tools like CSESpy are crucial for advancing our understanding of complex ionospheric and space weather phenomena that are otherwise challenging to investigate, thereby contributing significantly to advancements in space physics research.
How to cite: Papini, E., Follega, F. M., Piersanti, M., Battiston, R., and Diego, P.: CSESpy: a unified framework for data analysis of the payloads on board the CSES satellite, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15092, https://doi.org/10.5194/egusphere-egu25-15092, 2025.
How to cite: Knudsen, D. and Ghadjari, H.: Investigating the Role of Geomagnetic Activity in Loss of Navigational Capability in the Swarm Satellite Mission, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14321, https://doi.org/10.5194/egusphere-egu25-14321, 2025.
The ionosphere is the nearest natural plasma laboratory to the Earth. Ionospheric plasma waves serve as a important diagnostic tool for understanding space plasma and space weather. The CSES 01 mission and the DEMETER satellite made in-situ measurements of low-frequency plasma waves on sun-synchronous orbits and observed a large number of wave events, including whistlers, ionospheric hiss, and artificial very low-frequency (VLF) emissions, which revealed the local response of the ionosphere to natural hazards, space weather events, and human activities such as long-distance power line harmonic radiation and high-power VLF emissions. Moreover, the propagation of low-frequency electromagnetic waves in ionospheric plasma exhibits an obvious variation with altitude. However, it is not enough to study in-situ propagation characteristics of waves at different altitudes in the mid-latitude and low-latitude ionosphere. The micro-satellite LilacSat-3 provides an opportunity for this study. LilacSat-3, a thin disk-shaped satellite with a diameter of 1 meter, developed by Harbin Institute of Technology, will be launched into a sun-synchronous orbit with a variable altitude, gradually decreasing from an initial altitude of 500 kilometers. LilacSat-3 Plasma Waves Instrument (PWI), developed by School of Space and Earth Sciences, Beihang University, incorporates a pair of concentric loops designed to measure the magnetic component of ionospheric plasma waves and ionospheric disturbance caused by ground-based artificial VLF emissions along the normal direction of the satellite disk, providing a data source for revealing the characteristics of ionospheric response to space weather events in Low Earth orbit (LEO) and studying the propagation of artificial VLF emissions. The boomless concentric loop sensors exhibit intrinsic structural compatibility with the disk-shaped satellite. PWI adopts a high-accuracy data acquisition unit with 24-bit resolution and a maximum sampling frequency up to 200kHz, and is timed by Pulse per Second (PPS) signal with an accuracy of 1μs. The operating frequency range of PWI is up to 100kHz. LilacSat-3 mission is anticipated to be launched in mid-2025.
How to cite: Fu, Y., Zeng, L., Shi, F., Wu, F., Xi, R., and Cao, J.: The Plasma Waves Instrument for LilacSat-3 Mission, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11455, https://doi.org/10.5194/egusphere-egu25-11455, 2025.
Posters virtual: Tue, 29 Apr, 14:00–15:45 | vPoster spot 2
EGU25-396 | Posters virtual | VPS28
Local Time and Hemispheric Asymmetries of Field-aligned Currents and Polar Electrojet During May 2024 Superstorm PeriodsTue, 29 Apr, 14:00–15:45 (CEST) | vP2.6
This study examines field-aligned currents (FACs) and polar electrojet (PEJ) characteristics during the extreme May 2024 geomagnetic storms across dawn, dusk, daytime, and nighttime in both hemispheres. FAC and PEJ intensities were up to 9 times greater than usual, with equatorward FACs reaching -44º Magnetic Latitude. Maximum FACs and PEJ are larger at dawn than dusk in the Northern Hemisphere but larger at dusk than at dawn in the Southern Hemisphere. Dawn and duskside FACs correlate best with Dst or solar wind dynamic pressure (Pd) in both hemispheres. On the dayside (nightside), most FACs in both hemispheres are primarily correlated with Pd (merging electric field, Em or Pd). The PEJs correlate largely with Dst and partly with Em and Pd. Duskside (nighttime) currents are located at lower latitudes than dawnside (daytime), and northern currents are positioned more poleward than southern currents. The latitudes of peak FACs are most strongly correlated with Dst or Pd in both hemispheres. However, in the northern daytime sector, they are primarily influenced by Em. The latitudes of peak PEJ show the strongest correlation with Dst or Pd in both hemispheres, except on the northern dawnside, where they are primarily influenced by Em. The qualitative relationships between peak current density, corresponding latitude, solar wind parameters, and the Dst index are derived.
How to cite: Wang, H., Lühr, H., and Cheng, Q.: Local Time and Hemispheric Asymmetries of Field-aligned Currents and Polar Electrojet During May 2024 Superstorm Periods, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-396, https://doi.org/10.5194/egusphere-egu25-396, 2025.
EGU25-6137 | Posters virtual | VPS28
Dynamical Complexity in Swarm-derived Storm and Substorm Indices Using Information Theory: Implications for Interhemispheric AsymmetryTue, 29 Apr, 14:00–15:45 (CEST) | vP2.7
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 around the May 2024 superstorm, 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.
How to cite: Papadimitriou, C., Balasis, G., Boutsi, Z., and Giannakis, O.: Dynamical Complexity in Swarm-derived Storm and Substorm Indices Using Information Theory: Implications for Interhemispheric Asymmetry, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6137, https://doi.org/10.5194/egusphere-egu25-6137, 2025.
