With Swarm's successful data acquisition and accumulating
database there is a growing interest in usable supplemental
magnetic field measurements from other satellite missions.
There are either missions with dedicated science
instruments, but not focusing on the magnetometer
measurements - or missions, where platform magnetometers,
utilized by the satellite itself for attitude control and
fail-save, may be nevertheless suitable, in particular with
a revised calibration, for specific scientific issues: to
fill uncovered gaps in time or space or simply upgrade the
available overall density of measurements to underpin global
climatological studies. We will report on calibration
results of magnetic field data for the missions
ePOP/Cassiope, Cryosat, GOCE, GRACE, and CSES.

Usually for magnetometers on board satellites was taken care
of during ground calibration, which outcome is checked and
updated in-flight, at least during the commissioning phase.
On the other hand, incomplete correction on temperature,
aging effects of sensor or electronic or unexpected
environmental conditions may require additional in-flight
characterization of signals. Carefully selected data and
supplementing house keeping (HK) information may be able to
revise and improve the validity of the readings to a level
opening further scientific exploitation beside the initial
tender specifications.

For non-scientific platform magnetometers sticking even deep
in the satellite body or at least fairly close to it, the
availability of suitable HK data can be a limiting factor, the
optimal approach may also vary with the period of data,
available or in focus, the reachable or desired quality and
the intended use.

Examples of the characteristics of and the experiences with
the satellite missions mentioned above will be presented and
the archived improvements and quirks we came across. Partly
the validity of the calibration can be judged during further
scientific exploitation only. A close information circuit
between data optimization and scientific use had already
become fruitful.

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The efforts to investigate and characterize the Sun driven disturbances of the magnetic field measurements observed on the three Swarm spacecraft are continuing. Thanks to an intense and consistent effort of investigations and testing lead by DTU, Airbus, and ESA, a physical explanation of the observed disturbances on-board Swarm have been found. The fundamental cause of the disturbance is thermally induced electrical currents flowing in the grounding wires of the thermal insulating blankets mounted around the magnetic sensors on Swarm. Grounding of the thermal blankets on Swarm is performed using redundant wires connecting two rivets in the blankets to a common grounding point. These two wires together with the metal folio of the thermal blankets form a perfect current loop where the electrical current is driven by the temperature difference between the two rivets. This condition is present for the thermal blankets covering both the vector field magnetometer (VFM) as well as the absolute scalar magnetometer (ASM) and hence magnetic disturbances of both magnetometers can be expected.
This poster summarizes the results from the recent estimations of the contributions of these two disturbances on the magnetometer readings using five years of Swarm data.
Until the physical explanation of the disturbance was discovered, a purely empirical model of the disturbance was used, and the disturbance was assumed to only affect the vector field magnetometer readings. Consequently, only the VFM measurements were corrected, but with the new information provided by the physical explanation, some of this correction will be moved from the VFM measurements to the ASM measurements. As the disturbance at the ASM magnetometer sensor is almost exclusively in the East-West direction the effect on the magnetic field intensity measurements themselves is limited, however as this East-West disturbance correction is no longer applied to the VFM measurements a non-negligible change of the Swarm vector field data is a consequence. Investigations of the effect on the main field modeling of Earth's magnetic field are also presented here.

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The ESA's magnetic field mission Swarm, launched on 22 November 2013 into a near-polar orbit, is providing precise measurements of the magnetic signals from Earth’s core, mantle, crust and oceans, as well as the ionosphere and magnetosphere. This mission consists of the three identical satellites (Alpha, Bravo and Charlie). One (Swarm Bravo) flying in a higher orbit with an inclination of 87.8 deg and an altitude decaying from ~510 km while the other two satellites (Swarm Alpha and Charlie) that form the lower pair are flying side-by-side (~1.4° separation in longitude) at an altitude decaying from ~460 km and at 87.4 deg. inclination angle.
All the three Swarm satellite are equipped with the following set of identical instruments: Absolute Scalar Magnetometer (ASM), Vector Field Magnetometer (VFM), Star Tracker (STR), Electric Field Instrument (EFI), GPS Receiver (GPSR), Laser Retro-Reflector (LRR) and Accelerometer (ACC).
Here we present an update on the Swarm Absolute Scalar Magnetometer, Vector Field Magnetometer and Star Tracker instruments status and the improvements recently introduced in the L1B data processing.

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The Swarm Data, Innovation and Science Cluster (DISC) [1] is an ESA paid consortium of domain experts coordinated by DTU Space supporting the exploitation of the Swarm mission data. The objective of Swarm DISC is to foster an ecosystem of new innovative data products or services enhancing the return on investment with respect to the Swarm scientific results. Swarm DISC collects ideas for new products and services from the scientific community, evaluates them and recommends the selected ideas for implementation. The DISC call for ideas leads to series of new contracted projects targeted at development of new higher-level Swarm products.

The Swarm DISC activities are supported by the VirES for Swarm [2] data analysis and visualization platform, namely, by:

i) opening the machine-to-machine interface web service interface allowing fast convenient access to Swarm measurements, magnetic models and auxiliary data for the DISC scientists;

ii) provisioning of the VirES-connected Jupyter notebook based virtual research environment allowing DICS scientists to develop and perform custom Swarm data analysis;

iii) support for the new products/models developed by the DISC projects and development of new be-spoke visualization techniques for these products/models.

Examples of new DISC products [3] for which VirES support is provided:

- Auroral Electrojet and auroral Boundaries estimated from Swarm observations (AEBS): latitude profiles of ionospheric sheet current densities, auroral electrojet peaks and oval boundaries obtained by the Line Current and Spherical Elementary Current Systems methods, and auroral oval boundaries derived from the Field Aligned Current (FAC)

- Ionospheric plasma irregularities and fluctuations based on Swarm data (IPIR): time series of i) the plasma density and irregularities along the orbit from single satellite measurement, ii) local plasma conditions, iii) data related to geomagnetic regions in the ionosphere and iv) indication of severity of plasma irregularities.

- Average Magnetic field and Polar current System model (AMPS): AMPS model
New features initially developed specifically for DISC are usually ported to the VirES for Swarm platform for general public availability.

The outcomes of our VirES support activities for Swarm DISC will be presented.

References:
[1] http://www.space.dtu.dk/english/research/projects/project-descriptions/swarm/swarm_disc_itts
[2] https://vires.services
[3] https://earth.esa.int/web/guest/missions/esa-eo-missions/swarm/disc/new-products-services

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Swarm is the first European Space Agency (ESA) constellation mission for Earth observation, consisting of three identical satellites launched on November 2013 in near polar, circular orbits. One of the spacecraft (Swarm Bravo) has higher orbit, at an altitude of ~510 km, while the lower pair (Swarm Alpha and Charlie) are flying side by side, with 1.4° separation in longitude, at 460 km altitude. Each Swarm satellite is equipped with high-precision magnetometers (ASM and VFM), Electric Field Instrument (EFI), Star Tracker (STR), GPS Receiver (GPSR), Laser Retro-Reflector (LRR) and Accelerometer (ACC), and they are providing measurements of the Earth’s magnetic field and plasma environment in the Ionosphere with unprecedented accuracy.
EFI consists of two instruments: two Langmuir Probes (LP) and two Thermal Ion Imagers (TII), onboard each of the Swarm spacecraft.
The LPs provide continuous high quality observations of the electron density and temperature in the ionosphere and the spacecraft potential, which is auxiliary to the data processing of the TII instrument. No signals of degradation of the instruments have been observed.
The TII measures instead the velocity and temperature of the positive ions distribution in the ionosphere, and infers the ionospheric Electric field from ion velocity and magnetic field vector measured by VFM. TII is affected by a degradation of the images, due to the presence of contaminants inside the sensors. In order to deal with this problem, it has been adopted a Scrubbing procedure, which allows to obtain valuable scientific TII data during a number of orbits per day. The quality of TII data is continuously improving, and the final aim is to restore the continuous acquisition.
This paper will present an overview of the Electric Field Instrument after five years of operations, focusing on the most significant payload investigations to improve science quality, data validation activities and results along with future validation/calibration plans.

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Launched in November 2013, the three-satellite Swarm constellation is providing excellent measurements of the Earth's geomagnetic field and associated plasma environment. The mission is achieving remarkable scientific results covering a broad spectrum of topics from Earth’s core evolution and deep Earth flows to small-scale magnetosphere-ionosphere coupling, opening also the door for many innovating applications largely beyond the original scope of the mission objectives. To enable their full scientific exploitation, the Swarm data products have to meet the highest performance through constant improvements of the associated instrument processing facility and ground segment capabilities. In this respect, the Swarm ground segment and data quality teams provide essential services for the verification of all data products, as well as for the enhancement of processing algorithms. New versions of the Swarm Level 1B and Level 2 Cat-2 processors have been successfully deployed on the ESA operational platform on 17/09/2018 belong with the updated documentations to the new product format definition and processing algorithms. This deployment was associated to a second full-mission reprocessing campaign ensuring that way a full data product quality and format consistency since the beginning of the mission. The Swarm Data Quality team, with the support of external scientific experts perform routine data quality control and in-depth validations showing major improvements of L1-b data products, which will be ingested in new generations of Swarm-based advanced products for external and internal field models. This paper propose to provide a high level overview of key finding from Swarm data quality activities and to present the roadmap for extending the Swarm product portfolio, especially based on new cooperation with ESA’s partner agencies and promising multi-mission synergies between Swarm and complementary satellite observations

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Swarm is the fifth ESA Earth Explorer mission which was successfully launched on 22 November 2013. The main scientific objectives of the Swarm mission are to provide the best-ever survey of the geomagnetic field and its temporal evolution as well as the electric field in the atmosphere, using a constellation of three identical satellites.

The Swarm Payload Data Ground Segment (PDGS) is the mission's element in charge of the data processing, archiving, and dissemination; products quality control; and calibration and performance monitoring. The Swarm PDGS functionalities are implemented as a combination of dedicated systems and teams, and shared services. It has been working without major problems since the launch fulfilling all the mission's requirements.

Against the common perception that the Operational Ground Segments are static and conservative by its own nature, the architecture of the Swarm PDGS has been always evolving to respond to new operational and science requirements, the incorporation of new science products, and to improve the robustness, maintainability, and efficiency of the current system using the latest available techniques.

This poster will summarise the efforts of the Swarm DPGS team in several different areas: the evolution of the system architecture to make it maintainable in the long term, the flexible provision of the required storage and processing power for the first full mission reprocessing campaign; the improvements in the monitoring and report sub-systems; the simplification of the user’s data access, the integration of additional new data products coming from the Swarm DISC Processing Centres and the CASSIOPE/e-POP (Swarm-e) ESA TPM Mission; etc.

The planning and the execution of the first full mission L1-L2Cat2 reprocessing campaign will be describe in detail, and the lessons learned from this exercise will be outlined. The campaign was completed in September 2018, and it was the culmination of a coordinated multi-year and multi-team effort.

The reprocessing campaign has been executed on the Swarm Parallel Reprocessing Chain, a streamlined and cloud based version of the operational chain specifically optimised to maximise the processing throughput, achieving outstanding performances. The full reprocessed data is available to all users since 30 Sep. 2018. This provides a set of full consistent product datasets generated with the latest version of the operational processors and the with complete temporal coverage.

Finally, this contribution will also provide an outlook of the Ground Segment evolution plans, highlighting the aspects more relevant to the end-users as the processing status and forthcoming updates, datasets release outline, and the user data access.

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This contribution presents an overview of the most recent Swarm L2 products related to the mantle EM induction studies. Specifically, we discuss derivation of magnetospheric Q-responses and present updated M2 tidal magnetic signals from the most recent Swarm data. This presentation will cover aspects related to the data quality, reliability of the products and their uncertainty.
Further, derived Q-responses and recovered M2 tidal signals are inverted jointly to constrain the conductivity of the upper and lower mantle in the depth range between 10 and 1600 km.

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In the framework of SAFE (“Swarm for Earthquake study”) project, funded by ESA within the initiative "STSE Swarm+lnnovation”, we analysed Swarm three-satellite magnetic and electron density data for more than four years (1 Jan 2014 - 31 Aug. 2018) to look for possible earthquake related anomalies. In detail, we applied the search of satellite anomalies in the whole space-time interval of interest, avoiding high magnetic latitudes (|geomagnetic latitude|≤50°) and then we correlated them with earthquakes by means of a superposed epoch approach. Results have been also compared with analogous random simulations in order to assess their robustness. In general, our results point to a significant statistical correlation of the magnetic field signal and the electron density with seismicity. Both are superior with respect to random anomaly distributions with largest concentrations that are 2-3 times the corresponding of random simulations, corresponding to a deviation from the random mean by more than 40-50 σ, confirming ionospheric effects in the preparation phase of earthquakes.

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The Thermal Ion Imager (TII) instrument on Swarm measures, among others, the cross-track ion velocity, v_ct, which is used to derive the related electric field component as -v_ct x B. The validation / optimization (V/O) technique presented here aims to cross-check and possibly adjust the inferred electric field, in particular in the auroral region, by probing and minimizing the difference between two different estimates of the Pedersen conductance, one based on Ohm’s law and the other on the proxy of Robinson et al. (1987). The application of Ohm’s law requires prior knowledge of the ionospheric current, which is derived from the Swarm magnetic field data and whose accuracy has a significant influence on the V/O outcome. The use of V/O with electric field data derived from cross-track velocity requires as well that the probed configuration is reasonably close to 1-D, as e.g. in the case of auroral arcs. This condition can be checked primarily by conjugate optical data, or by comparing specific signatures from two Swarm satellites (provided that the distance between the two satellites is neither too small, nor too large, with respect to the relevant scale length). We shall present event study results illustrating both the validation and optimization aspects of the V/O technique, as well as discuss these results in the context of the specific event conditions.

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The plasma of the ionosphere is abundant with small-scale (100-200 km) inhomogeneities that may result in the distortion and loss of GPS signals, thus the corruption of ground-based GPS measurements. The plasma inhomogeneities are accompanied by scale-dependent intermittent (i.e. turbulent) fluctuations in the magnetic field. Most frequently, the ionosphere disturbances occur at +-15° from the dip equator and at high latitudes, around the aurorae region. The equatorial events are the results of equatorial spread F (ESF) or equatorial plasma bubble (EPB) phenomena, while the auroral irregularities are related to field aligned currents (FAC). Our paper aims at presenting a methodology for the detection of plasma irregularities through their typical intermittent magnetic fluctuations, along the low-Earth orbits of the triplet of the Swarm mission. We use the 50 Hz VFM magnetic records of the three satellites transformed to mean-field aligned coordinate system. It is shown that the equatorial plasma disturbances exhibit intermittent/turbulent magnetic features in the compressional (field-aligned) component, while the FAC related phenomena appear mostly in the transversal magnetic field. We develop an index for quantifying the intermittent non-linear feature of magnetic time-series in terms of time and position of the Swarm satellite. The index is called intermittency index (IMI). A Matlab computer code is applied for the automatic and routine computation of IMIs along the Swarm orbits, both for the compressional and transversal components.
The index and the methodology are validated in three ways. First, an obvious comparison between indices obtained from magnetic records of the adjacent Swarm A and C spacecraft is carried out. Next, in the cases of equatorial events, the correlation between the occurrences of intermittent magnetic fluctuations and plasma bubble events are investigated. The plasma bubble occurrences are measured via the ionospheric bubble indices (IBI), that are provided by the Swarm mission as a level 2 product. Finally, on global scale, we investigate the correlations between intermittent magnetic fluctuations at the Swarm orbit and GPS signal distortions detected by ground GPS receivers. Distortion of the carrier signals are characterized by GPS amplitude and phase scintillation indices (S4, Prms) observed at Global Navigation Satellite System (GNSS) stations.

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ESA Swarm three satellite constellation , launched on 22 November 2013, has demonstrated to be a powerful tool to monitor the geomagnetic field and plasma in ionosphere. China Seismo-Electromagnetic Satellite (CSES) ZhangHeng-01 was successfully launched on 2 February 2018. CSES satellite is equipped with nine payloads dedicated to search for possible disturbances in ionosphere related to earthquakes. In this study, we firstly present a comparison between the geomagnetic field components measured by VFM (Vector Field Magnetometer) on-board Swarm and those one measured by HPM (High Precision Magnetometer) on-board CSES ZhangHeng-01. We will compare also the plasma electron density measured by Swarm EFI (Electric Field Instrument) and CSES LAP (LAngmuir Probe). For CSES electron density, we will show a preliminary background characterization during geomagneticaly quiet time. A definition of a reliable background is important in the framework of the research of possible electromagnetic disturbances induced by lithospheric activity. Finally we will show an application of Swarm and CSES data to search for electromagnetic disturbances preceding a large earthquake (M7+) and possibly due to earthquake preparation phase as expected by the Lithosphere-Atmosphere-Ionosphere coupling model (e.g. Freund et al. 2011, Kuo et al. 2014). We apply some similar techniques already successfully applied to Swarm data for three large earthquakes: 2015 M7.8 Nepal, 2016 M7.8 Ecuador and 2017 M8.2 Mexico earthquakes (De Santis et al. 2017, Akhoondzadeh et al. 2018, Marchetti et Akhoondzadeh 2018).
The integration of different satellite data and the launching of a large constellation of satellites permit to increase the coverage and so the probability to catch electromagnetic perturbations from active seismic faults, so they help in studying and understanding the different interactions between the different Earth system layers, as foreseen by Geosystemics (De Santis et al. 2015).


References:

• Akhoondzadeh M., De Santis, A., Marchetti, D., Piscini, A., Cianchini, G., (2018). Multi precursors analysis associated with the powerful Ecuador (MW = 7.8) earthquake of 16 April 2016 using Swarm satellites data in conjunction with other multi-platform satellite and ground data. Advances in Space Research 61, 1, 248-263.
• De Santis, A., De Franceschi, G., Spogli, L., Perrone, L., Alfonsi, L. Qamili, E., Cianchini, G. et al. (2015). Geospace Perturbations Induced by the Earth: The State of the Art and Future Trends. Physics and Chemistry of the Earth, Parts A/B/C, May. Doi:10.1016/j.pce.2015.05.004.
• 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
• Marchetti D., Akhoondzadeh M. (2018) Analysis of Swarm satellites data showing seismo-ionospheric anomalies around the time of the strong Mexico (Mw=8.2) earthquake of 08 September 2017, Advances in Space Research, 62, 3, 614-623. DOI: 10.1016/j.asr.2018.04.043

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The Swarm spherical Langmuir Probes (LPs) are part of the Electric Field Instrument (EFI) and consist of two sensors on the ram side of each spacecraft that provide 2 Hz electron density, electron temperature, and the plasma potential data along the orbital trajectories. The EFI rectangular faceplate (FP), including two Thermal Ion Imager (TII) enclosures, is biased negatively to provide 16 Hz passive ion current measurements during periods when the TII is inactive. Standard data processing provides electron density from the LP probes using the orbit-motion-limited (OML) approximation for current versus applied bias, under the assumption that the ion composition is singly-ionized atomic oxygen and that the ions are not drifting in a frame co-rotating with the Earth. The same drift speed approximation is used to derive ion density from the planar faceplate. It can be shown that the LP and FP measurements can be combined to refine the ion density estimate and additionally determine the reduced (or effective) ion mass together with the bulk flow velocity parallel to the satellite track of the surrounding plasma environment. Kinetic simulations provide a basis for applying first-order corrections to the current-vs-voltage relations for both the LP and FP measurements. During nighttime and for the present low solar activity conditions, it turns out that Swarm frequently observes a lighter effective ion mass consistent with the transition region from ionosphere to plasmasphere (i.e., significant amounts of H+ and He+). Charging effects in the vicinity of the spacecraft pose a challenge to estimate reliably the along-track plasma bulk flow velocity from the induced emf between the two LP probes.

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We describe a new satellite-borne sensor for measuring ion bulk drift and temperature in the terrestrial ionosphere. The mini plasma imager (MPI) is an electrostatic analyzer based on the Swarm thermal ion imager (TII) designed to be deployed on a 3U (10 cm x 10 cm x 34 cm) nanosatellite. The MPI detector is a charge-coupled device directly sensitive to ions that operates on a 24 V supply. Operation is achieved with end-to-end voltage differences less than 100 V. A laboratory prototype MPI and a rocket-borne version have been developed at the University of Calgary under contract to the Canadian Space Agency. Lab characterization demonstrates the MPI matches the designed ion drift measurement performance of the TII at 2 samples per second for plasma densities greater than 10⁴/cm³. Technical and measurement characteristics are described. Results from the VISIONS-2 sounding rocket campaign will be shown. A preliminary mission-level study has demonstrated the feasibility to accommodate an MPI with a scientific magnetometer and Langmuir probe on a nanosatellite to do targeted studies of the auroral ionosphere at relatively low cost.

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Geomagnetic daily variations at mid and low-latitudes are generated by electric currents in the E-region of the ionosphere, around 110 km altitude. As part of the Swarm level 2 project, we developed a series of global, spherical harmonic models of geomagnetic daily variations from a combination of Swarm and ground-based measurements. The latest model, Dedicated Ionospheric Field Inversion 4 (DIFI-4), released in April 2018, includes over four years of Swarm data. As more Swarm data become available, and Swarm local time coverage improves, it becomes possible to apply the DIFI approach to shorter time intervals (e.g. two years) in order to investigate the year-to-year variability of ionospheric currents. Such variability could be caused by the geomagnetic secular variation, which makes features such as the dip equator and the South Atlantic Anomaly slowly move and change in shape, and is currently not included in the DIFI algorithm. It could also be caused by some intrinsic year-to-year variability of the average ionospheric current systems that would not be accounted for by the current solar cycle parameterization. In this presentation, we report on the preliminary results of a follow-up project, xDIFI, aimed at investigating the year-to-year variability of daily variations by using magnetic data over a longer time interval. Specifically, we produce a series of DIFI-like models based on pre-Swarm magnetic satellite (e.g., CHAMP) data, Swarm data (until the end of 2018) and ground-based observatory data. The obtained models cover a little less than 20 years, i.e. almost two solar cycles and a period during which the main magnetic field intensity changed by as much as 5% in some locations.

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ESA Swarm satellites carry a magnetometry payload consisting of an absolute scalar magnetometer (ASM), a relative flux gate vector magnetometer (VFM), and a set of star trackers (STR). The primary role of the ASM is to provide precise 1 Hz absolute field intensity measurements, while the VFM and STR provide the additional data needed to accurately reconstruct the vector field. Each ASM instrument, however, can also produce 250 Hz scalar burst mode, if requested. This ASM burst mode has been run for several days early on during commissioning of the mission, revealing an expected ability to detect Extremely Low Frequency (ELF) whistlers within the 20-120 Hz frequency range. These signals are due to electromagnetic signals produced by neutral atmosphere lightning events, which penetrate the ionosphere and get dispersed as they propagate along their path between their ionospheric entry point and the Swarm satellites. Preliminary studies have shown that such dispersion could potentially be used to recover very useful information about the state of the ionosphere to test and possibly improve ionospheric reference models such as IRI and NeQuick. These results have now prompted ESA to soon start running additional ASM burst mode data sessions on a more regular basis (with the intention to produce such data two weeks per month simultaneously on Swarm Alpha and Bravo). These ASM burst mode data are to be produced by IPGP and will be distributed as a new “ASM 250 burst mode science data” Swarm product. In this presentation, we will report on the status of the production and distribution of this new Swarm data product, and will also provide examples of the way these data can be used for ELF whistler detection and ionospheric investigations.

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The CSES satellite carries a High Precision Magnetometry (HPM) payload consisting of two fluxgate magnetometers (FGM1 and FGM2) and an absolute scalar magnetometer (Coupled Dark State Magnetometer, CDSM) next to each other at the tip of a dedicated boom pointing earthwards, the CDSM being the furthest away, to ensure optimal magnetic cleanliness. Attitude restitution needed to provide vector field measurement in a terrestrial reference frame is ensured thanks to a set of three star sensors sitting on the main body of the satellite. In addition, the CSES also carries a suite of instruments for measuring high-frequency electromagnetic signals and plasma parameters (Search Coil Magnetometer, Electric Field Detector, Langmuir Probe, High Energetic Particle Package). These payloads are currently providing data between -65° and +65° latitudes, and very promising preliminary results have already been presented by the CSES team during the 8th ESA Swarm Data Quality Workshop (SDQW#8, 09-12 October 2018, Frascati, Italy). High-precision magnetic and plasma data are also currently been acquired by the satellites of the ESA Swarm mission, which have been in continuous operation since November 2013. Comparing data from both the CSES and Swarm missions, and field models derived from these data, is thus of the highest interest to assess the potential of possible future joint use of the two data sets for many science applications. In this presentation, we will report on some comparisons carried out by Swarm magnetic and plasma expert groups, taking advantage of a subset of CSES data kindly provided by the CSES team for such a purpose. It is expected that such comparisons could also help both missions refine their calibration and validation procedures for the mutual benefit of both missions.

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TEMPO (“Is The Earth's Magnetic field POtentially reversing? New insights from Swarm mission”) has been a 2-year research project co-funded by The Living Planet Programme of ESA and INGV (Rome, Italy). The main objective of this project has been the detailed analysis of the South Atlantic Anomaly (SAA) evolution using the new magnetic dataset provided by the Swarm mission. The study of the SAA is an important challenge nowadays, not only for the geomagnetic and paleomagnetic community, but also for other areas of the Earth Observation. This monitoring has revealed that this anomaly has been growing for the last 200 years with alternating accelerated and decelerated periods. Its deep origin is due to the presence of two patches of reversal polarity at the Core-Mantle Boundary that are growing and moving westward. We have demonstrated that these reversal patches are mainly controlled by the quadrupole field and this agrees with the previous phase of a geomagnetic transition. However, the current value of the geomagnetic dipole moment is not so low when compared with recent paleomagnetic data for the Holocene and with the mean value for the entire Brunhes geomagnetic polarity (i.e. the last ∼0.8Ma), and this is an important key in the preparation phase of an imminent geomagnetic transition.
On the other hand, we have discovered a previously unreported link between the minima of acceleration of the South Atlantic Anomaly extent area and the occurrence of geomagnetic jerks for the last two decades. This fact is of particular interest because could shed light on the origin of geomagnetic jerks. We have confirmed that the occurrence of the geomagnetic jerks is related to the pulses of the secular acceleration of the geomagnetic field at the Core-Mantle Boundary, in particular to the minima. A new pulse in 2016.0 epoch seems to reinforce the hypothesis on the presence of a standing magnetohydrodynamics wave with a quasi-6-year periodicity that is found between the periodicities of the series analysed in this work (3 and 7 – 8 years), and could point to the triggering of a new geomagnetic jerk in the next few years.
Finally, we have presented a preliminary regional geomagnetic field model over the SAA area based on Swarm satellite magnetic data and ground observatories data generated using the R-SCHA technique. The incorporation of other satellite data (Magsat, Ørsted and CHAMP satellite missions) and cross-marine data will provide a robust model that will be a useful return product of the TEMPO project for the scientific community.
As a complementary work, we have also explored the possible connection between the geomagnetic field and the climate, a question highly debated in the last fifty years, using as input data the evolution of the SAA area extent and the Global Sea Level (GSL) rise for the last 300 years. For this purpose, we have used an innovative information-theoretic tool, i.e. the transfer entropy, as a good candidate for determining, not simply the possible existence of a connection, but even the direction in which the link is produced. The results seem to support the existence of a relation between the SAA and the GSL, with a confidence level of about 90%. This finding provides new clues on the existence of a link between the Earth’s climate and the geomagnetic field in the past and on the physical mechanism involved, because, thanks to the application of the transfer entropy, we have determined that the sense of the connection seems to go from the system that produces geomagnetic field to the climate system. Of course, the connection does not mean that the geomagnetic field is fully responsible of the climate changes, rather that it is an important driving component to the variations of the climate.

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