After 9 years of operation, the ESA’s SMOS (Soil Moisture and Ocean Salinity) mission continues providing good quality full polarimetric Brightness Temperature (TB) data to generate frequent and global maps of soil moisture over landmasses and surface salinity over the ocean thanks to its unique payload, MIRAS (Microwave Imaging Radiometer using Aperture Synthesis). At its operating frequency (1.41 GHz), there is a non-negligible effect that must be compensated, called Faraday Rotation which rotates the electromagnetic field components coming from the Earth microwave radiation when propagating through the ionosphere.
The Faraday rotation angle (FRA) magnitude depends on the frequency, geomagnetic data, and the total electron content on the ionosphere [1] [2]. Currently, the FRA is theoretically estimated in SMOS by using a formulation that depends on two external sources where the first one provides geomagnetic field data and the second one, ionosphere data read from a global VTEC database with an interval of two hours. In order to get improved geophysical parameter retrievals, the FRA must be directly recovered from the SMOS full-pol TB data in a continuous way.
Latest advances in image reconstruction led to improving third and fourth Stokes parameters [3] making possible the instantaneous retrieval of the FRA with SMOS full-pol brightness temperature [4]. However, due to the large thermal noise, spatial bias, and image reconstruction artifacts, FRA retrievals for a single snapshot present high errors.
A previous work showed that FRA could be directly retrieved at boresight from SMOS full-pol TB with good accuracy by using a smart spatio-temporal filtering strategy [5]. However, averaged boresight FRA estimations are not representative across the complete SMOS field of view (FoV), that is, if the averaged boresight FRA is assigned to all pixels in the FoV, a large systematic bias appears across the FoV [6].
In this work, a new methodology is presented in order to retrieve FRA from SMOS radiometric data in the SMOS overpass using most of the extended alias-free FoV. The method is based on deriving SMOS VTEC maps to use them in the FRA correction instead of the ones from the VTEC database. To make a robust VTEC retrieval despite all the factors that make it challenging, a temporal and spatial filtering strategy has to be applied. The size of the filters has to be thoroughly analyzed and chosen taken into account the tradeoff between the mitigation of the noise effect and the accuracy of the VTEC retrieval. We developed in [6] an end-to-end simulator to assess the performance of the different tested approaches by using simulated TB images. By obtaining the VTEC on the SMOS overpass, the FRA can be retrieved because both variables are directly proportional.
This methodology is allowing the recovery of VTEC maps directly from full-pol SMOS data giving promising results. We are currently working on the validation of these retrieved SMOS VTEC maps by comparing them to combined GPS files [7] and with the TEC values provided in the L2OS product [8]. Next step will be focused on correcting the TB by using the retrieved FRA from SMOS following the proposed methodology and evaluating the impact on the quality of the TB images.
REFERENCES
[1] D. M. Le Vine and S. Abraham, “The effect of the ionosphere on remote sensing of sea surface salinity from space: Absorption and emission at L band,” IEEE Transactions on Geoscience and Remote Sensing, vol. 40, no. 4, pp. 771–782, April 2002.
[2] S. H. Yueh, “Estimates of Faraday rotation with passive Microwave polarimetry for microwave remote sensing of earth surfaces,” IEEE Transactions on Geoscience and Remote Sensing, vol. 38, no. 5, pp. 2434–2438, September 2000.
[3] L. Wu et al. , “Radiometric performance of SMOS full polarimetric imaging,” IEEE Geoscience and Remote Sensing Letters, vol. 10, no. 6, pp. 1454–1458, November 2013.
[4] S. H. Yueh, “Estimates of Faraday rotation with passive Microwave polarimetry for microwave remote sensing of earth surfaces,” IEEE Transactions on Geoscience and Remote.
[5] I. Corbella, L. Wu, F. Torres, N. Duffo and M. Martin-Neira. “Faraday Rotation Retrieval Using SMOS Radiometric Data”. IEEE Geoscience & Remote Sensing Letters, Vol.12, iss. 3, pp. 458- 461. 2015.
[6] R. Rubino et al., "Direct faraday rotation angle retrieval in SMOS field of view," 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), pp. 697-698, 2017, doi: 10.1109/IGARSS.2017.8127047.
[7] Schaer, S., Gurtner, W., & Feltens, J. (1998, February). IONEX: The ionosphere map exchange format version 1. In Proceedings of the IGS AC workshop, Darmstadt, Germany (Vol. 9, No. 11).
[8] Vergely, J.-L., P. Waldteufel, J. Boutin, X. Yin, P. Spurgeon, and S. Delwart (2014), New total electron content retrieval improves SMOS sea surface salinity, J. Geophys. Res. Oceans, 119, 7295–7307, doi:10.1002/2014JC010150.

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There is an increasing awareness of the vulnerability of our modern infrastructure to the adverse effects of space weather, and of the need to take protective measures. This has led to an increasing need for effective communication about related scientific disciplines, such as solar-terrestrial physics and geospace science. Communication should not only be aimed at fellow specialists, but also at an audience without a solid background in these disciplines, including students, newcomers to the field from sectors affected by space weather, as well as the general public.

Space weather is characterised by complex physics, including magnetohydrodynamic and electrodynamic interactions between the Sun, the heliosphere, Earth's magnetosphere, ionosphere and upper atmosphere. The phenomenon involved are well outside of the realm of most people's day-to-day experience, and finding good analogies to explain the physics is not trivial. Measurement data in the domain is very sparse, compared to the very large extent of spatial and temporal scales at which variability takes place.

Standard graphics for space weather alerts, watches and warnings are often limited to simple traffic light charts, which can be effective for their purpose, but do not shed light on the phenomena behind them. Graphics used among scientists, such as stacked time series graphs of magnetic field components, solar wind properties and geomagnetic activity indices, are not easy to interpret by the uninitiated.

In this talk, several experiments with more advanced visualisations will be shown. These include using animation to communicate the temporal aspects of phenomenon such as geomagnetic storms, and placing 'raw' near-Earth space and ground-based measurements in their 3D geospatial context, instead of using timeseries. In addition, the output of complex physics-based models, such as WACCM-X and TIE-GCM can be used to visualise on a global scale what is measured, for example by ESA's Swarm satellites, on a local scale.

Advantages and limitations of these approaches will be discussed, in the contexts of communication for outreach, teaching and scientific understanding.

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We present a major update of the GOCE thermosphere density and wind data, obtained from this mission’s very precise acceleration, tracking and attitude measurements, as well as housekeeping data from its drag free control system.
The updated data set contains a number of improvements and new features: 1) We make use of the newly reprocessed GOCE Level 1B input data; 2) we have introduced a new high fidelity satellite geometry model and improved gas-surface interaction model, which results in improved accuracy and consistency with similarly processed data sets from related missions (CHAMP, GRACE and Swarm) and ground-based wind observations, 3) the data set now includes unique acceleration-derived vertical winds, and 4) it includes thermosphere observations from the GOCE deorbit phase special dataset, covering the last three weeks of the mission in October-November 2013, based on accelerometer data down to about 180 km and GPS tracking down to 150 km altitude.
We have compared the old and new versions of the GOCE data, and compared the new data with empirical models, physics-based models, and data sets from related missions.

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Atmospheric drag is the major non-gravitational perturbation acting on Low Earth Orbiting (LEO) satellites at altitudes up to about 1000 km. The drag depends, among other parameters, on the neutral density of the thermosphere which is usually provided by diverse empirical and physical models. The thermosphere is mainly driven by the dynamics of energy from the Sun during nominal and space weather events. Empirical models have been derived since 1961 using observations such as mass spectrometer, incoherent scatter radar and orbital data (satellite acceleration from precise orbit determination), as well as accelerometer data from CHAMP, GRACE, GOCE and Swarm missions. Knowledge on the density of the Earth’s thermosphere and exosphere is a prerequisite for planning satellite missions, precise orbit determination (POD), orbit and re-entry prediction, as well as collision avoidance of artificial satellites orbiting the Earth at altitudes below 1000 km. Systematic offsets may arise between the thermospheric density of any two models that need to be addressed using a proper calibration procedure.

We present results on using satellite laser ranging (SLR) observations to three spherical LEO satellites at the altitude of 248 to 425 km to scale the thermospheric density provided by the empirical model NRLMSISE00 and the physics-based model TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation Model). Both models provide neutral density as a standard output. TIEGCM provides additionally electron and ion densities. Therefore, the prominent role of the ionosphere in shaping the thermosphere is intrinsically considered in this work. For our analysis, we use SLR observations to the ANDE-P satellite from 16 August 2009 to 3 October 2009, the ANDE-C satellite from 16 August 2009 to 26 March 2010 and SpinSat from 29 December 2014 to 21 June 2015, i.e. we consider periods of low and high solar activity. We investigate the difficulty to range these satellites due to their high angular velocity. We inter-compare the scale factors obtained for the above mentioned models. Additionally, we present the modelling aspects, the parameterization and the selective challenges of the mathematical representation of the neutral density from the models with thermosphere-ionosphere coupling.

Area B - Board 210

The CHAMP, GRACE, GOCE and Swarm satellites have been very productive missions to improve the understanding of atmospheric dynamics and coupling processes in the thermosphere-ionosphere region. Accelerometers and GPS-receivers on board of these satellites provided, and are providing, high-resolution thermosphere products. However, scale differences of such satellite data with respect to empirical models have so far been largely neglected or removed using ad hoc scale factors. The source of these differences arises from errors in the satellite geometry, aerodynamics and gas-surface interactions (GSI) modelling. Previously used simplified models could not provide high-fidelity information about satellite outer surfaces and energy exchanges between atmospheric particles and satellites.
Within this study, we aim to reduce these uncertainties by using an enhanced geometry and aerodynamic modelling with a better characterization of gas-surface interactions. The satellite accelerations have been reprocessed using newly estimated GSI parameters leading to high-fidelity density and wind estimates. Long periods and attitude manoeuvres have been investigated in order to provide an overview of GSI modelling influence and the associated thermospheric products sensitivity. In this work, the improved densities and winds are presented and compared with empirical atmospheric models. The presented improved products are expected to be useful to the thermosphere-ionosphere science community to further increase the understanding of atmospheric dynamics as well as the effects of space weather and space climate on satellite orbits.

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The objective of this work is to check the space weather impact on the Global Navigation Satellite System (GNSS) Ground Based Augmentation Systems (GBAS) LATPOS and EUPOS®-Riga station daily observations in randomly selected 2-3 months in each year during the 11-year period of 2007-2017.
The five-minute resolution GNSS observation coordinate results are computed in kinematic mode using a scientific post-processing Bernese GNSS Software Version 5.2. The results are obtained for the 30 GBAS stations of the LATPOS and EUPOS®-Riga networks covering the territory of Latvia. The cases of disturbed coordinates are found amongst 8640 computed results in the selected months period for each station at least for 2 months in each of the 11 years. The identified events of station coordinate disturbances are assessed as the predominant result of the influence of ionospheric scintillations. The statistics of the disturbance occurrences are analysed in relevance with geomagnetic storms registered by international services. Events of both disturbances and station domes of affected GNSS reference stations are listed and a comparison with a list of geomagnetic storms is performed. The subsets of most affected GNSS reference stations are discovered depending on their latitude and elevation.
It is concluded that the five-minute resolution GNSS observation coordinate results computed in kinematic mode for the ground based continuously operating GNSS reference stations represent substantial statistics for the recognition of space weather anomalies. GBAS stations are mainly affected by space weather and, probably, less affected by localities multipath due to the predominant highly elevated placement of antennas which are not obstructed by trees or various constructions.
It is concluded that the effect of space weather is different at the same given time in different localities. The research results of this work expose the space weather irregular changes and irregular GNSS positioning disturbances in GBAS stations in Latvia at the latitudes around 57ᵒN. The statistics of disturbances will be presented.

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Key challenges identified in the COSPAR-ILWS space weather roadmap [Advances in Space Research, 2015: DOI: 10.1016/j.asr.2015.03.023] include: 1) understand and quantify key aspects of space weather: physical processes, impact on technology and society; 2) establish mechanism for rapid implementation of latest advances in understanding, observations and modeling into space weather applications and operations; 3) facilitate transition to effectively functioning and operating, information-sharing, global space weather community. To address these challenges and to demonstrate the benefits of a global coordination to space weather stakeholders and international space weather community the COSPAR Panel on Space Weather (PSW) has facilitated the establishment of an active network of International Space Weather Action Teams (ISWAT). The ISWAT initiative is aiming to serve as a global community voice and a bottom-up push for innovation and coordination between multiple guidelines from national/regional agencies and international organizations. Here we report on the latest updates, opportunities, and future plans arising from the Near-Earth Radiation and Plasma Environment ISWAT topical team. The work presented builds upon the prior momentum of the International Forum for Space Weather Capabilities Assessment developed in partnership with and by the international Community Coordinated Modelling Center (iCCMC). This ISWAT team aims to improve radiation belt modelling, both in forensic understanding of prior events where as much historical data as possible can be aggregated, as well as in forecast model accuracy and functionality. Fixed polar LEO, MEO, GEO, and GTO orbits are the primary initials targets. Performance is planned to be assessed against metrics which are derived based on various radiation and plasma effects. These include those arising from surface and deep charging, component and solar cell aging and degradation, and a variety of single event and total dose effects. A series of forensic and forecast model comparison challenges, which compare the results from as many international models as possible, is also being planned. The plasma and radiation ISWAT team further contributes to the overall goals of the COSPAR ISWAT project which target space weather impacts into four targeted areas: advancing understanding, improving utilization of available observations, improving modeling capabilities, recommendations for future mission planning. All teams work in a coordinated effort towards realization of global roadmap goals and generation of inputs for global roadmap updates. The presentation will highlight recent progress and invite broader community feedback and active participation in the ISWAT process, providing an overview of all ISWAT team, but in particular focusing on the Near-Earth Radiation and Plasma Environment ISWAT team.

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“Characterization of IoNospheric TurbulENce level by Swarm constellation (INTENS)” is a study recently approved by ESA in the framework of “EO Science for Society Permanently Open Call”. The aim of the study is to investigate the nature of geomagnetic field and plasma parameters (i.e., electron density and temperature) fluctuations, as well as their scaling features during different geomagnetic disturbance conditions, to unveil the role played by the magnetohydrodynamic (MHD) turbulence on the ionospheric environment in creating multi-scale plasma structures and plasma inhomogeneties. This goal will be pursued through the analysis of Swarm constellation measurements of the Earth's magnetic field as well as electron density and temperature. The knowledge of these parameters is expected to provide a characterisation of the nature and level of the ionospheric turbulence on a local scale, which can be displayed either along a single satellite orbit or through maps over the region of interest. The same parameters can be used also to study variations of the scaling features of the geomagnetic field and ionospheric plasma according to different geomagnetic disturbance conditions and interplanetary magnetic field orientations; this will provide a characterisation of the different ionospheric turbulence regimes of the medium crossed by the Swarm constellation, on scales from hundreds of kilometres to a few kilometres. The investigation proposed is an example of the capability of Swarm data to provide new insights on the ionosphere-magnetosphere coupling and, at the same time, to stimulate the development of methods of analysis based on the scaling features of the geomagnetic field and plasma parameters as local indicators of the ionospheric conditions. Some preliminary results of this study will be presented. They will be compared with those previously obtained and published, and discussed in the global framework of the ionospheric turbulence.

(*) The members of the INTENS team are: A. Anastasiadis, A.Z. Boutsi, I. Coco, I. A. Daglis, F. Giannattasio, O. Giannakis, M. F. Marcucci, C. Papadimitriou, S. Pau, M. Pezzopane, R. Tozzi and G. Vasalos

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The topside ionosphere extends from the F2-layer peak height, around at 300 km, to the lower boundary of the plasmaphere, located around at 1000 km. A reliable modeling of this region is extremely important, particularly for telecommunication’s purposes, because it contains a large fraction of the Total Electron Content (TEC), i.e. the integral of the electron density from ground to the GPS satellites orbit. However, an exact knowledge of the physical and chemical state of the plasma in this region is really challenging.
This is testified by the fact that the International Reference Ionosphere (IRI) model does not represent properly the real features of this ionospheric region. For this reason, we developed an empirical method to model the topside ionospheric region, and its extension to the plasmasphere, over Europe. Electron density values recorded by Langmuir probes on-board European Space Agency Swarm satellites constellation and F2-layer peak parameters (foF2 and hmF2) provided by the IRI UP (International Reference Ionosphere UPdate) method are used as anchor points to calculate topside effective plasma scale height values (H0) by fitting the NeQuick topside function through such anchor points. Calculated effective scale heights are then modeled by binning them as a function of foF2 and hmF2, obtaining two-dimensional grids of the median effective plasma scale height. The result of this study is then a tool, namely maps of H0 as a function of foF2 and hmF2, to reliably model the topside over the European region using the NeQuick topside function, once the F2-layer characteristics, that is foF2 and hmF2, are known, either measured or modeled.
The method has been statistically evaluated by comparing topside TEC values calculated by integrating electron density values provided by the “updated NeQuick” with those measured by Swarm satellites.

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Thermospheric winds in the low-latitude ionosphere are responsible for driving ionospheric dynamo currents, which are among the strongest currents on the dayside. In particular, the latitudinal structure of the equatorial electrojet (EEJ), an intense narrow band of current flowing in the dayside E-region along the magnetic equator, is highly dependent on zonal winds in both the E- and F-layers at low-latitudes. The EEJ typically exhibits a strong peak on the magnetic equator, with reverse current "sidebands" about 5 degrees off the equator in both the northern and southern hemispheres. The strength, position, and asymmetries of these sidebands are strongly influenced by zonal winds flowing inside and above
the E-layer. The latitudinal current structure of the EEJ has attracted much interest, both recent and historical, since it can provide information on more fundamental physical processes responsible for driving the large-scale ionospheric dynamo, which are challenging to measure directly.

Measurements of the winds in the equatorial region of the ionosphere are sparse, and climatological wind models can exhibit errors of tens to hundreds of meters per second in the zonal wind component. In this study, we propose a method to infer vertical profiles of the zonal wind at low-latitudes by combining physics-based modeling of the EEJ with magnetic field measurements recorded by Swarm. A forward physics-based model is used to solve for the full latitudinal EEJ current at a given longitude, using climatoligical models to specify the ionospheric densities, temperatures, and winds. A perturbation wind field is defined to allow deviations from the climatology which is determined by fitting the modeled EEJ current to Swarm measurements. These perturbation wind profiles can then be used to study the structure of low-latitude neutral tides, and also to provide corrections to existing climatological wind models. Improving the quality of thermospheric wind models is important for developing next-generation physics-based models of the 4D ionosphere system.

Area B - Board 216

Abstract
One of the important aspects of lightning phenomena at low altitudes is that the energy release is happening in highly localized regions of space leading to formation of spark channels with temperatures ∼25000K and plasma with electron densities exceeding 1017cm−3. So strong disturbances in the upper atmosphere should be source of changes in the ionosphere and can be registered by satellites operating there.
Particularly strong phenomena as TLEs (sprites, jets, elves, halos) associated with the thunderstorm activity are responsible for electromagnetic connections and interactions between atmosphere, ionosphere and magnetosphere.
DEMETER has clearly shown, that thunderstorms and sprites can affected the ionosphere even at altitude of its orbit (680km). The Swarm constellation comprises 3 identical satellites. Two of them are operating on the circular, polar orbits with initial altitude 460 . Third one has also circular orbit, but with altitude 530. The orbits of the first 2 satellites are in almost the same plane, but third one is close to be perpendicular to the first two. The payload containing Vector Field Magnetometer, Absolute Scalar Magnetometer and Electric Field Instrument among other allows to study the effects in the ionosphere generated by thunderstorms. The discussion of the observation of the electron density and temperature disturbances, fluxes of the energetic electrons as well as ELF/VLF emissions over strong thunderstorm areas done by DEMETER and Swarm satellites will be given in the presentation.
The cross correlation between the ground based (WERA system) and Swarm registration of the ULF/ELF waves related to the thunderstorm and TLE’s will additionally be presented.
Acknowledgments. This work was supported by grant NCN 2017/27/B/ST10/02285. ESA is acknowledge for access to Swarm data in the context of activities performed for the Swarm4Anom contract 4000112769.
References
M. Parrot et al. ,Ionospheric density perturbations recorded by DEMETER above intense thunderstorms, J.Geophys.Res., 2013.
Clilverd, M. A et al., Determining the size of lightning- induced electron precipitation patches, J. Geophys. Res., 2002
D.K. Sharma, et al., Lightning induced heating in the ionosphere, Atmosfera, 2004
F. Bourriez, et al.A statistical study over Europe of the relative locations of lightning and associated energetic burst of electrons from the radiation belt, Ann. Geophys. 2016

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The ARASE satellite mission aims to study the acceleration and loss mechanisms of relativistic electrons during geospace storms by observing both "the cause", i.e., magnetospheric waves responsible for the acceleration/loss, and "the effect", i.e., the corresponding energetic electron flux populations seen by the particle detectors onboard. Ground-based verification of the precipitating electron fluxes serves as a crucial complement for this approach.
EISCAT incoherent scatter radar measures the height-dependent density of free electrons, and its time-dependent response to variable ionising radiation from space, yielding information on both the ionisation source processes (solar electromagnetic radiation, energetic particle precipitation, cosmic rays) and their consequences on the atmosphere (changes in chemistry, energetics and dynamics).
We introduce a novel inversion technique for determining the EPP characteristics, i.e., precipitation flux density spectrum and ionisation rate profile. In addition, potential chemical consequences of the energetic particle precipitation are assessed. In our approach, a detailed ion chemistry model (SIC) is used as a time-dependent forward model in the MCMC based inversion.

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Since 2016 the Swarm DISC (Data, Innovation, and Science Cluster) have published open "Call for Ideas" in support of the identification, development and production of new products and services related to the Swarm satellite constellation trio.

Based on the submitted ideas, several sessions of "Invitations To Tender" have resulted in projects delivering new products or services to the scientific community. A series of new ideas have been selected for implementation.

We will present the ongoing progress of the open "Call for Ideas" under Swarm DISC, inviting further ideas for new products or services, based on Swarm data alone or in combination with data from other sources, that will enhance the scientific return on investment of the Swarm mission.

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Measurements of vertical ion drift and electron temperature from the Swarm electric field instruments are used to estimate the ion-neutral momentum-transfer collision frequency in the high-latitude topside ionosphere. This parameter is fundamental in ionosphere-thermosphere interaction physics, yet its determination has been limited to observations from ground-based radars and sounding rockets in the E region ionosphere. Under certain conditions ion upflow is linearly related to electron temperature in a process known as ambipolar diffusion, with a slope inversely proportional to the product of the ionospheric density scale height and the ion-neutral collision frequency. We report statistical evidence for this linear relationship in the Swarm data at altitudes near 500 km in the topside ionosphere. We examine the conditions under which the collision frequency can be determined with Swarm, and examine its variability.

Area B - Board 220

Thermal (<10 eV) O+ ion energization and field-aligned transport are critical processes of magnetosphere-ionosphere-thermosphere coupling. The O+ ions can be heated transversely to the local magnetic field through wave-particle interaction or frictional heating due to ion-neutral collisions. The Swarm-Echo scientific payload, also known as the Enhanced Polar Outflow Probe (e-POP), carries eight instruments specifically designed to study microscale characteristics of ion energization and outflow processes in the topside ionosphere at altitudes from 325 to 1500 km. The Suprathermal Electron/Ion Imager (SEI) instrument onboard e-POP has the capability of resolving 2-D ion distributions at 10-ms time scale, or less than 100-m spatial scale, and with a bulk velocity resolution of the order of 25 m/s. Direct measurements of particles, waves and magnetic fields have led to several discoveries. First, with complementary observations from the DMSP satellites and ground-based radars, we find intense (>1.6 km/s) O+ ion upflows within the cleft ion fountain near 1000 km during quiet times. Such large ion upflow velocities have been previously reported only during active periods. These ion upflows are mainly driven by ambipolar electric fields due to soft electron precipitation from the magnetosphere.

Second, in order to understand the energy input from plasma waves into the ionospheric ion heating process, we present the first statistical study (24 events) of low-energy O+ ion heating and its relation to low-frequency (several Hz up to 1 kHz) waves, usually referred as broadband extremely low-frequency (BBELF) waves, in the ionosphere. We find that transverse O+ ion heating in the ionosphere can be intense (T⊥ up to 4.5 eV) at altitudes as low as 350 km, confined to very narrow regions (~2 km across B), is more likely to occur in the downward current region and is associated with BBELF waves. This amount of ion heating cannot be explained by frictional heating, and the correlation of ion heating with BBELF waves suggests that significant wave-ion heating is occurring and even dominating at ionospheric altitudes. Surprisingly, the majority of the ion heating events are associated with core ion downflows rather than upflows. This may be explained by a downward pointing electric field in the low-altitude return current region.

Area B - Board 221

The ionospheric Alfven resonator (IAR) is an area of space that, due to sharp Alfven speed gradients, has the ability to trap electromagnetic plasma wave energy, where it bounces in the Alfvén mode between near-Earth space and the lower ionosphere. Here we present research that, by comparing induction coil magnetometer data from the Canadian Array for Realtime Investigations of Magnetic Activity (CARISMA) with world lightning occurrence data from the World Wide Lightning Location Network (WWLLN), has revealed strong evidence that energy released in terrestrial lightning storms can enter this resonator. Energy from lightning strikes is ducted through the Earth-Ionosphere cavity, generating the well-defined Schumann resonances (SR) with a fundamental frequency ~7.8 Hz. Our results show that in addition to the Schumann resonances, the lightning energy perturbs magnetic field lines as it propagates, generating Alfvén waves that travel up the magnetic field lines towards near-Earth space, and in regions where the ionospheric Alfvén resonator is active, these Alfvén waves are reflected back down from the peak in the Alfvén speed, resulting in one or more echo pulses in the magnetometer data. Using the superposed epoch analysis technique, reveals two critical characteristics of this paradigm: 1) the pulse-echo(s) signal, which occurs on the scale of 1-2 seconds, is defined by the characteristics of the local resonator, and this is most clearly shown by the spectra of the signal; and 2) this pulse-echo signal has been measured for lightning occurring at large distances, beyond 8000 km from the magnetometer instrument, which contradicts earlier assumptions that the lightning pulse needed to be local (or less than 2000 km away) from the ionospheric Alfvén resonator active region of the ionosphere. This provides an interface between space weather and the terrestrial global electric circuit. Future work should reveal more details about this previously unknown pathway for magnetosphere-atmosphere interaction.

Area B - Board 222

During magnetically quiet times, the solar quiet current system and the equatorial electrojet, both in the E-region ionosphere in about 100 km height, are sensitive to forcing from above and below. These electric current systems are well monitored by magnetometer stations on ground as well as geomagnetic satellite missions like Swarm. We present recent results that quantify the influence of solar flux and geomagnetic main field strength on the long-term trend of these current systems. We also identify variability in the equatorial electrojet caused by forcing from atmospheric tides and waves. We find the equatorial counter electrojet, an occasionally developing (westward) electric current that flows opposite to the (eastward) equatorial electrojet, to be of particular interest for such studies.

Area B - Board 223

Auroral phenomena are at the heart of magnetosphere–ionosphere–thermosphere coupling and were/are investigated by numerous spacecraft missions and ground experiments. Here we concentrate on observations by the three-satellite Swarm mission, launched by ESA in November 2013, and by the single spacecraft Fast Auroral SnapshoT (FAST) mission, launched by NASA in August 1996 (end of the mission in April 2009). The two missions are, in some sense, complementary: While FAST is better tuned to auroral observations, sampling a broad variety of particles and fields data, the auroral data from Swarm are less diverse, but probed at multiple points. Consequently, common examination of data from both Swarm and FAST can unravel significant features of auroral electrodynamics, more difficult to pinpoint by looking separately into one or the other data set. One such feature is the longitudinal gradients (e.g., in the field-aligned or ionospheric current, electric field, or conductance), which are typically neglected, but potentially important at certain times and locations. For instance, longitudinal gradients are likely to matter during the substorm growth phase, when the (initially) 1D arc that will break up at the substorm onset prepares to transform into 2D aurora. Longitudinal gradients at the low altitude end of the magnetosphere–ionosphere system are illustrated with FAST and Swarm observations. Further implications for the whole auroral current circuit are briefly discussed as well.

Area B - Board 224

Studies are conducted by financial aid from National Centre of Science (Grant no. UMO-2017/27/B/ST10/02285).

Strong convective events in Europe are regular, especially in the summer season, when there is an advection of warm tropical air from the southern region. High water vapour content in the warm air, convection, atmosphere instability and strong vertical thermal gradients, are favouring development of strong cloud complexes, such as MCS. They are created by strongly developed Cumulonimbus clouds, and they can cover an area up to 100 000 km2. They characterize with significant hail and naval precipitation, strong winds, which can reach the level of 150 km/h, many atmospheric discharges and relatively long time of the occurrence, from 6 up to 12 hours. The analysis of data will be divided into three different parts.
First part of the analysis is conducted with using METEOSAT9 satellite, which allow to identify thunderstorms by using IR camera which is installed on board. Using this setup, the analysis of the height of cloud peaks will be conducted, which can reach level of 15 km. That means, the penetration of the tropopause and reaching lower parts of the stratosphere by clouds. This is possible due to strong updrafts in the thunderstorm structure. In addition synoptic data will be used for an analysis of thermodynamic conditions, which occurred in the thunderstorm activity period. The second part of the research is focused on the analysis of the thunderstorms, with using ground station Hylaty, which has been placed in Polish mountains in Bieszczady region. The station is equipped with two orthogonal antennas, which allows to detect signals in ELF band (Extremely Low Frequencies). It belongs to the global system WERA (World ELF Radiolocation Array) granting us to study signals from strong thunderstorm all over the world. Based on those measurements we are able to use developed inverse solutions, which allow to compute dipole moments of –CG and +CG (Cloud-to-Ground). The last part of our studies covers the search of correlations between data from the DEMETER satellite and constellation of SWARM satellites, to the data from Hylaty station. The satellites have the possibility to measure VLF (very low frequencies) and ELF waves, which let us look for the relation between measurements on the orbit, and the ground measurements. Thus differences and changes in the ionosphere and magnetosphere due to thunderstorm activity. The highest activity of MCS is during evenings, where at the same period of time DEMETER has its flybys over Europe.
This is the first complex project of the study of the interactions between atmospheric discharges and the ionosphere-magnetosphere system. Simultaneous satellite and ground measurements allow for deeper analysis of those processes. We expect significant progress in understanding them and their role in the physics of the higher atmosphere. Atmospheric discharges are local and are manifested by impulses. During a single discharge, the enormous energies are released and they have a huge impact on ionosphere, causing mesoscale disturbances. It influences telecommunication and the accuracy of GPS systems, so understanding of these phenomenon have a practical meaning.

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Post sunset equatorial ionospheric plasma irregularities are a unique study case to investigate ion-neutral coupling in the low-latitude ionosphere, additionally, they are known to disturb radio wave communication.

We use high precision magnetometer data from 10 years of CHAMP (2000-2010) and the recent the Swarm (2013-today) LEO missions high precision magnetometer data to derive a global model of their occurrence rate in the F region ionosphere (300-500km). The model is derived by appropriate functions, e.g., parameterizing season, longitude, solar flux, local time and persistence to describe the significant probability distribution. The model shows very good agreement to earlier climatological investigations based on other satellite missions.

Identification of the plasma irregularities is through correlation between the high resolution insitu magnetic and electron density time series. This relation tells about ionospheric pressure-gradient electric currents. We find a typical global distribution of positive and negative correlation values opening new questions on processes of local ionospheric energy balance.

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During the night in the F-region, equatorial ionospheric irregularities
manifest as plasma depletions observed by satellites and cause fluctuations in
radio signals. In November 2013, the Swarm satellites developed by the European
Space Agency (ESA) were launched to study the Earth’s magnetic field. Using
their Langmuir Probes (LPs) and the faceplate of the electric field instrument
(EFI), these satellites are capable of measuring electron density within the F
region globally at frequencies of 2 Hz and 16 Hz, corresponding to scales along
the orbit of 4 km and 500 m, respectively. This statistical study examines the
seasonal and longitudinal dependence of ionospheric density irregularities in
the low latitude region using the 16 Hz electron density measurements of the
Swarm satellites’ faceplate for the period October 2014 - November 2017. Two
different methods i.e., absolute (∆Ne ) and relative (∆Ne/Ne ) density
perturbation, were used to quantify the level of ionospheric irregularities. In
addition to variations with local time, the two methods also show difference in
latitude distribution of irregularitiess. The irregularities characterized by
the absolute variation ∆Ne are distributed symmetrically about the magnetic
equator, while the relative variation ∆Ne/Ne is not entirely symmetric. In
general, the two methods reproduce the global seasonal and longitudinal
distribution of equatorial plasma bubbles (EPBs) as presented in previous
studies. EPBs were observed at all longitudes between ±15° geomagnetic
latitude in the equinox with maximum values in the African-Atlantic-South
American longitudes. EPBs occurred mostly in the African region during June
solstice and were totally suppressed in the Atlantic-South American region.
During the December solstice, EPBs occurred mostly in the Atlantic-South
American region but were suppressed in the other longitude regions, especially
in the Pacific region. However, only the seasonal and longitudinal
distribution of absolute density perturbation agrees with that of
scintillation. The longitudinal distribution of EPBs may be explained by the
steep electron density gradient derived along the satellite tracks.

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The Swarm satellites fly at altitudes which at polar latitudes are generally assumed to only contain currents that are aligned with the local magnetic field. Therefore, disturbances along the main-field direction are mainly signatures of auroral electrojet currents, with a relatively smooth structure due to the distance from the currents. Here we show that, superimposed on this smooth signal is an irregular pattern of small perturbations, approximately 0.1 to 1 nT, which are anti-correlated with the plasma density measured by the Langmuir probe. We show that the perturbations can be remarkably well reproduced by assuming they represent a jxB force which balances the plasma pressure gradient implied by the density variations. The associated diamagnetic current, previously reported to be most important near the equator, appears to be a ubiquitous phenomenon at all latitudes, although it is often eclipsed by other disturbances in the auroral oval.

Area B - Board 228

Different types of ultra-low frequency (ULF) waves, such as dayside compressional Pc3-Pc4 waves, Pc2 and Pc1 waves, Pc3-Pc4 field line resonances, night side and day side Pi2s, etc. have been successfully identified in the topside ionosphere. ULF wave observations in this region can help us to understand the wave structure in the magnetosphere, wave propagation, and also the effects of the ionosphere (transmission, reflection, mode conversion). Because of the fast orbiting speed of the Swarm satellites, Fourier analysis is not applicable in many cases, special techniques (wavelet analysis, maximum entropy method) are needed to resolve ULF signals, as well as to discriminate between spatial and wave structures. In this paper, we summarize the results of a study of Pc3 compressional waves observed at low-Earth-orbit (LEO) by the Swarm satellites. The presented results are based on an almost five-year-long continuous dataset. A particular emphasis is put on investigating the global coherence and phase structure of these waves, as well as their relation to ground signals and interplanetary conditions. This is the first time that a study of this nature has been carried out using magnetic field data from multiple LEO satellites.

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In a previously-published study we compared Swarm satellite data with images from THEMIS ground-based all-sky cameras [Wu et al., JGR, 2017] and showed that roughly 60% of multiple auroral arcs occur within a single, broad, upward, quasi-static field-aligned current (FAC) sheet, with little return current between arcs. Further study of this data shows that approximately 1/3 of multiple arc systems host regions of fluctuating magnetic and electric fields (Alfven waves) in the 0-8 Hz range, in many cases exhibiting a standing wave pattern as seen by comparing the amplitude ratio and phase difference of E and B spectra. Nagatsuma et al., [1996] shown that the superposition of incident and reflected Alfven waves causes the electromagnetic fluctuations inside the “boundary current system”, which is termed to describe the narrow (~1°) up-and-down current pair poleward of the region 1 FAC. However, the relation of Alfven waves and large-scale FAC structure is not clear. In this study, we present a statistical study of the MLT/MLAT distribution of standing Alfven waves and their relation to auroral arcs and large-scale field-aligned currents.

By collecting 154 events of multiple arcs observed with regions of Alfvenic fluctuations, we find that the majority of the events are located around midnight. Various large-scale FAC patterns, composed of 2-9 current sheets, have been observed with Alfven waves. In most cases, Alfven waves are found to be located on the poleward side of the FAC systems. Multiple arcs are located in the upward current sheet equatorward of the peaks of wave spectral density. However, in some cases, especially in the dawn and dusk sectors with the typical two-region FAC, Alfven waves exhibit peaks in spectral density in the center of the region 1 current, which is equatorward of the “boundary current system” reported in the literature. The location of these waves and their relation to currents and auroral arcs can provide information relevant to determining the source and roles of these waves in arc generation and magnetosphere-ionosphere coupling.

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In the last two decades, the understanding of the geomagnetic field has experienced a strong impulse due to the large amount of continuous observations provided by satellite missions. At the end of 2013 a new era in magnetic observations began with the successful launch by the European Space Agency of the three-satellite Swarm constellation, because its innovative geometry has opened the way for new and original investigations, of which this paper is an example. Notably, taking advantage of high precision vector magnetic measurements made at two different altitudes, we estimate the ionospheric current density. In detail, we map the radial, meridional, and zonal components and total intensity of the ionospheric current density at the satellites’ altitude at high latitudes. This is made through a mathematical procedure that allows calculating the curl of the geomagnetic field from vector magnetic measurements made onboard Swarm Alpha and Bravo while they were orbiting at an average altitude of around 450 and 510 km, respectively. After removing main, crustal and magnetospheric geomagnetic fields by means of CHAOS-6 model, data are arranged into matrices whose elements are needed to evaluate a discretised form of the fourth Maxwell’s equation. The availability of a large amount of data, i.e. of 1 Hz measurements made during nearly five years, can be used to draw a significant climatology of high-latitude large scale ionospheric current systems and investigate at the same time their properties as a function of geomagnetic activity, season and Interplanetary Magnetic Field orientation. Specifically, to characterize the geomagnetic activity, the AE index is used, being AE the geomagnetic index that best represents disturbed conditions at high latitudes. The structure and features obtained through the method here proposed are compared with current systems previously found by other methods. The comparison shows that most of the obtained results are consistent with the main known features of ionospheric currents such as field-aligned currents and Hall and Pedersen currents. This method, therefore, allows reconstructing all the three components of the ionospheric current density directly from satellite measurements, without the need to resort to mathematical models.

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Knowing the auroral FAC dynamics, i.e. sheet motion and orientation, is scientifically important by providing insight into the dynamics of distant magnetospheric regions, and can help the design of better FAC models or improve the existing Swarm FAC products.

In principle, obtaining the FAC sheet motion requires to separate the spatial and temporal variations in satellite measurements, a possibility provided only by multi-spacecraft missions like Swarm. For such a mission, the differences in position and time when the satellites detect the current sheet can be fed into a timing technique to infer its velocity. However, the Swarm orbital motion poses some particular challenges. Indeed, with a time separation between the two lower satellites flying side-by-side, swA and swC, ranging roughly between 7 and 10 s, and an orbital velocity of about 7.5 km/s, the required precision in the timing information is too high in order to properly characterize the FAC motion (i.e. the velocity error uncertainties below the average values reported in the literature of approx. 100 m/s). In these circumstances, one can think to take advantage of the measurements provided by the upper satellite, swB, when it leads or trails the lower satellites by roughly few hundred seconds. However, swB is orbiting the Earth in a different plane, that slowly drifts with respect to the planes of swA and swC by 22.5 deg. every year, and therefore the effect of FAC curvature may become important.

In this presentation, we evaluate the performance of two methods designed to study the FAC motion with Swarm, one based on the combination of two-satellite timing technique and Minimum Variance Analysis (a technique to estimate the current sheet planarity an orientation), and the other one based on the three-satellite timing technique. The curvature of FAC sheet is considered in both methods by making some reasonable assumptions. Several Swarm auroral crossing events are analyzed and the results provided by the methods are compared.

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Spatial patterns embedded in 2-D signals can be investigated by using different linear and nonlinear analysis methods operating in both time and frequency domain.
A simple linear decomposition method mostly used in geophysics is the method of empirical orthogonal function (EOF) analysis, used to find both time series and spatial patterns. It is a statistical procedure through which a set of observational data related to different variables is decomposed into a set of linearly uncorrelated variables named principal components (Pcs). The first principal component exploits the largest possible variance (i.e., takes into account the largest data variability), while the remaining components are ordered in terms of decreasing variance under the constraint that they are all orthogonal. The basis functions are typically found by computing the eigenvectors of the covariance matrix of the data set.
A different method, the multivariate empirical mode decomposition method (MEMD), which is an extension of the empirical mode decomposition method, allows to analyze multivariate patterns by extracting intrinsic spatial components with different characteristic scales without any a priori fixed assumptions on linearity and stationarity conditions, through a self-adaptive process. This means that MEMD is able to describe local (in terms of space) non-stationary (in terms of time) variations due to nonlinear components (in terms of amplitude variations in space and time), representing the inherent multi-scale and complex nature of the analyzed signal.

Here, we apply both the EOF and the MEMD methods to characterize spatial patterns of external vertical component of the geomagnetic field at low and middle latitudes as a function of geomagnetic activity level recorded by Swarm constellation during a period of two years from 1 April 2014 to 31 March 2016. We show how MEMD method is particularly suitable to avoid misleading results produced by the EOF one. Indeed, the MEMD method extracts the main modes which contribute to the determination of the geomagnetic field of external origin during quiet and active periods by using few modes to recognize the different contributions coming from sources external to the Earth in the magnetic signal and to reproduce the realistic equivalent currents responsible for the recorded magnetic field variations. This study is an example of the potential of MEMD method which can be used to give new insights into the analysis of the different sources responsible of the geomagnetic field of external origin and, at the same time, it can be used as a good filter in the analysis of the geomagnetic field of external origin permitting us to separate the ionospheric contribution from both the magnetospheric one.

References

Alberti T., Multivariate Empirical Mode Decomposition analysis of Swarm data. Il Nuovo Cimento, 41 C, 113, 2018.

Alberti T., Giannattasio F., De Michelis P., Consolini G., Linear vs. nonlinear methods for detecting magnetospheric and ionospheric current systems patterns. in prep., 2018.

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On September 28th, 2018 at 10:02:45 UTC, a 7.5MW earthquake occurred in Indonesia (0.256°S 119.845°E; 20 km depth), which is a complex convergence region of many different plates (e.g. Australia, Sunda, Pacific, and Philippine Sea Plates). The epicentre was located in the middle of the Molucca microplate. The earthquake’s ground shaking produced vast damages to about 680,000 houses and, unfortunately, more than 2,100 victims and around 4,600 injured people.
In this study, we search for possible Lithosphere Atmosphere Ionosphere Coupling (LAIC) effects as described by different models (e.g. Freund et al. 2011, Kuo et al. 2014, Pulinets and Ouzounov, 2011), identifying possible phenomena that could be linked to the earthquake preparation phase.
Firstly we conduct an analysis of the earthquakes happened in this region from 5 years before and select different areas and depths as the region presents high seismic activity at depth until more than 500 kilometres. We then concentrate only to shallow lithospheric earthquakes (depth ≤ 50 km), finding a seismic acceleration preceding the mainshock. Furthermore, possible alterations in physical and/or chemical composition of the atmosphere (e.g. skin temperature, aerosol optical thickness, etcetera) are investigated from metereological/climatological dataset provided by European Center for Medium-range Weather Forecast (ECMWF) and NASA / MERRA2. In particular, we calculate the typical historical mean and standard deviation (based on about 38 years) for the investigated parameters for the area surrounding the epicentre. Then we compare the historical values with the ones in the months prior to the Indonesia earthquake, concentrating to the values that overpass the two standard deviations, a method already successfully applied to Central Italy earthquakes (Piscini et al. 2017).
To investigate for possible ionospheric disturbances due to seismic activity we analyse the Swarm magnetic and electron density data during geomagnetic quiet time to avoid possible disturbances due to solar activity. For the first time, we investigate also the data provided from the recent launched mission China Seismo-Electromagnetic Satellite (CSES) ZhangHeng-01. To analyse the satellite data we apply different techniques to search for different effects. One of them is based on the comparison of the root mean square inside a small moving window compared with the root mean square of the whole track (i.e. inside +/-50 degrees of geomagnetic latitude) and it is intended to search for rapid variations of the parameter under investigation due, for example, to particles emissions. For example, this technique was successfully applied to 2015 M7.8 Nepal earthquake (De Santis et al. 2017). Other techniques that we apply are based on the analysis of the absolute values of the parameters (e.g. Y component of magnetic field, magnetic absolute scalar intensity, electron density) to search if their values overpass by a certain threshold the typical values (for example Ne greater than 30% the background in geomagnetically quiet time). With both techniques, we find interesting anomalies (for example with values that are greater than 48%, 65% and more with respect to background) that will be discussed to understand their possible relationship with the impending earthquake, i.e. the eventual lithospheric source of them.
Finally, comparing the anomalies detected in lithosphere, atmosphere and ionosphere, it is possible to try to infer a possible chain of physical phenomena that could happen before the earthquake occurrence. With this study, we show the utility to collect and maintain the large Earth Observation dataset from mainly ground and satellite data monitoring that in the future also could be very useful to monitor in real time the seismic zones to predict earthquakes, although nowadays, this is still not possible.


References:

• De Santis A., Balasis, G., Pavón-Carrasco, F.J., Cianchini, G., Mandea M. (2017). Potential earthquake precursory pattern from space: the 2015 Nepal event as seen by magnetic Swarm satellites, Earth and Planetary Science Letters, 461, 119-126.
• Freund F. (2011). Pre-earthquake signals: Underlying physical processes, Journal of Asian Earth Sciences, 383–400
• Kuo, C. L., Lee, L. C. and Huba. J.D. (2014). An improved coupling model for the lithosphere-atmosphere-ionosphere system. J. Geophys. Res. Space Physics, 119, 3189-3205, DOI: 10.1002/2013JA019392
• Piscini A., De Santis, A., Marchetti, D., Cianchini, G. (2017). A Multi-parametric Climatological Approach to Study the 2016 Amatrice–Norcia (Central Italy) Earthquake Preparatory Phase. Pure and Applied Geophysics, 174, 10, 3673-3688.
• Pulinets S, Ouzounov, D., (2011). Lithosphere‑Atmosphere‑ ionosphere coupling (LAIC) model‑an unified concept for earthquake precursors validation, J. Asian Earth Sci, 41(4–5):371–382.

Area B - Board 235

The years 2007, 2008,- 2009 and 2016 have been considered to identify anomalous
behaviours of electron density variations in relationship with geomagnetic Ap and AE
indexes.
The variations of the ionospheric parameter foF2 from Rome ionosonde and electron density
from CHAMP and SWARM satellites Langmuir probes are analysed. Each observed
anomaly has been then associated to the related geomagnetic condition. The ionospheric
anomalies detected during quiet geomagnetic conditions from Rome ionosonde data and,
when it is possible, from electron density satellite data are examined to check if the
relationships obtained between pre-earthquake ionospheric anomalies and Central Italy
earthquakes, in particular for L’Aquila and Amatrice earthquakes, are confirmed.

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A new method to extract neutral composition (O, O 2 , N 2 ), exospheric temperature Tex, vertical plasma drift ,W, and the total solar Extreme Ultraviolet (EUV) flux with λ≤ 1050Å from routine ionosonde bottom-side electron density, Ne(h), observations has been proposed. The method can be
used around noontime hours for all months of the year at middle latitudes where the ionospheric F-layer is formed by solar EUV radiation. The uncertainty of the retrieved neutral gas density coincides with the announced absolute uncertainty ±(10-15%) of Challenging Minisatellite Payload/Space Three-axis Accelerometer for Research mission (CHAMP/STAR ) neutral gas density observations. The method provides statistically significant better results with Mean Relative
Deviation (MRD) < 15% ; Root Mean Square (RMS) < 0.5 in a comparison with modern empirical models Mass Spectrometer-Incoherent-Scatter ( MSISE00), Jacchia-Bowman 2008 (JB2008), and Drag Temperature Model 2013 ( DTM2013) (MRD>15% and RMS> 0.5). The thermospheric
parameters retrieved for the St. Patrick Day magnetic storm are compared to Swarm-B accelerometer observations. The proposed method may be considered as an useful tool for analyses of the state of the upper atmosphere under various geophysical conditions.

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Machine learning techniques have been successfully introduced in the fields of Space Physics and Space Weather, yielding highly promising results in modelling and predicting many disparate aspects of the geospace environment. Magnetospheric ultra-low frequency (ULF) waves can have a strong impact on the dynamics of charged particles in the radiation belts, which can affect satellite operation. Here, we employ a method based on Fuzzy Artificial Neural Networks in order to detect ULF waves in the time series of the magnetic field measurements on board the low-Earth orbit (LEO) CHAMP and Swarm satellite missions. The outputs of the method are validated against a previously established, wavelet-based, spectral analysis tool, that was designed to perform the same task, and show encouragingly high scores in the detection and correct classification of these signals.

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Recently, many novel concepts originated in dynamical systems or information theory have been developed, partly motivated by specific research questions linked to geosciences, and found a variety of different applications. This continuously extending toolbox of nonlinear time series analysis highlights the importance of the dynamical complexity to understand the behavior of the complex Earth's system and its components. Here, we propose to apply such new approaches, mainly a series of entropy methods to the time series of the Earth's magnetic field measured by the Swarm constellation. Swarm is an ESA mission launched on November 22, 2013, comprising three satellites at low Earth polar orbits. The mission delivers data that provide new insight into the Earth's system by improving our understanding of the Earth's interior as well as the near-Earth electromagnetic environment. We show successful applications of methods originated in information theory to quantitatively studying complexity in the dynamical response of the topside ionosphere, at Swarm altitudes, to space weather events.

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