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Ref: ESA-EOPG-MOM-MIN-222 Date 20/11/2018 From Jerome Bouffard [ESA] Based on contributions from: Rune Floberghagen [ESA], Enkelejda Qamili [SERCO], Lorenzo Trenchi [SERCO], Christian Siemes [RHEA], Kathy Whaler [UoE], Claudia Stolle [GFZ], Kirsti Kaurustie [FMI], Gauthier Hulot [IPGP], Guram Kervalishvili [GFZ], Roger Haagmans [ESA], Eelco Doornbos [DUT], Greg Enno [UoC], Antonio De la Fuente [ESA] and Nils Olsen [DTU]

The 8 th Swarm Data Quality Workshop Summary and Recommendations Report

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WORKSHOP HIGHLIGTHS

q The 8th Swarm Data Quality Workshop (DQW#8) held in ESA ESRIN from Monday 08th October (afternoon) to Friday 12th October 2018 (morning).

q The Swarm DQW#8 was a great success, with more than 110 talks, numerous discussions, 11 sessions, 150 participants (~50% more than previous DQWs), among which 17 % were non-EU members (mainly from China, Korea and North America).

q The main objectives of the workshop were to: o Provide an overview of Swarm Mission status to the user Community o Update the data quality status from Magnetic, Electric, GPSR and accelerometer measurements o Discuss new Swarm-based Scientific results q Beside the usual Cal/Val topics, this Swarm DQW#8 has also allowed to address new technical, scientific and strategic challenges related to: o Swarm-based Multi-disciplinary applications o Swarm-based Data processing virtual environments o Swarm-based Machine Learning methods o Multi-mission synergies (e.g. with CryoSat, Goce, e-POP, CSES etc.) q The Swarm DQW#8 has allowed to identify and compile key recommendations (> 40) and feedback for future Swarm product evolutions and activities

q The Swarm DQW#8 was an occasion to discuss potential synergetic benefits obtained through collaboration initiatives with ESA’s partner agencies and other sensor systems.

q A dedicated session on Swarm / Chinese CSES mission synergies were organized for the first time to further discuss and structure future joint Cal-Val activities and scientific cooperation.

q The next Swarm DQW will be held in Prague (Czech Republic) in mid-September 2019.

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TABLE OF CONTENT

1 CONTEXT AND MEETING SCOPE ...... 7

2 SESSION SUMMARY ...... 8 2.1 INTRODUCTION ...... 8 2.2 MAGNETIC FIELD INSTRUMENTS ...... 8 2.3 ELECTRIC FIELD INSTRUMENTS ...... 9 2.4 GPS AND ACC INSTRUMENTS ...... 10 2.5 ADVANCE PRODUCTS FOR INTERNAL FIELDS ...... 11 2.6 ADVANCE PRODUCTS FOR EXTERNAL FIELDS ...... 12 2.7 SWARM –CSES SYNERGIES ...... 13 2.8 SWARM - ECHO ...... 15 2.9 MULTI-MISSION SYNERGIES ...... 16 2.10 SWARM & SPACE 4.OI ...... 17 2.11 SUMMARY AND CONCLUSIONS ...... 18

3 RECOMMANDATIONS ...... 19

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1 CONTEXT AND MEETING SCOPE

The Swarm Data quality team organized a meeting inviting Swarm multi-disciplinary scientists and instruments experts (see Appendix I) with the objective to listen their view and collect innovative ideas for future Swarm activities and products, targeting new processing algorithms, correction improvements, AI-based emerging applications, data assimilation and multi-mission synergy.

The 8th Swarm Data Quality Workshop (SDQW#8) held at ESA/ESRIN on 08-12 October 2018 and was structured around 11 main sessions (see detailed agenda in Appendix II):

• Session 01: Mission overview • Session 02: Magnetic field measurements • Session 03: Electric field measurements • Session 04: GPSR and accelerometer measurements • Session 05: Advance products for Internal Field • Session 06: Advance products for External Field • Session 07: Swarm - CSES Synergies • Session 08: Swarm – Echo • Session 09: Multi-mission Synergies • Session 10: Swarm & SPACE 4.0I • Session 11: Summary and Conclusions

Moreover, large time slots were dedicated to discussions and brainstorming.

All the SDQW presentations are available at: https://earth.esa.int/web/guest/missions/esa-eo- missions/swarm/activities/conferences/8th-data-quality-workshop

The scope of this document, mainly based on contributions from Swarm DQW#8 session chairs, is to summarize the main points discussed during the workshop and compile key user recommendations and feedback, which should be translated into future Swarm-based products and scientific activities.

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2 SESSION SUMMARY

2.1 Introduction Swarm ESA and DISC teams introduced first the meeting objectives and provided a brief overview of Swarm data portfolio and characteristics, allowing to address a growing number of scientific challenges and operational applications in the areas of Near-Earth Space Physics, Earth's magnetic field variations, geophysics and emerging topics. The status of the mission remains green, regarding Platforms, Payload systems and PDGS infrastructures. The status of Swarm data quality is also nominal. New processors have been successfully deployed in operation on 17/09/18 and used for the first full mission reprocessing campaign. The reprocessing campaign was completed in September 2018, and it was the culmination of a coordinated multi-year and multi-team effort. The reprocessed data is available to all users since 30/09/2018. This provides a set of full consistent product datasets generated with the latest version of the operational processors and with complete temporal coverage. As a lesson learnt of this reprocessing exercise, it was mentioned the importance of having more frequent periodic releases of operational processors in order to plan new mission reprocessing campaigns. Cal/Val results on the new L1/L2 dataset have shown major improvements. Status of the CSES mission, Swarm Echo and Vires visualisation tools were also briefly presented during the mission overview session but further discussed in session 7, session 8 and session 10, respectively.

2.2 Magnetic Field Measurements During the “Magnetic field measurements” splinter session it was reported on the status of the three following instruments on-board the Swarm spacecraft: cIn addition, the quality of the Magnetic data (with Product Baseline and File Counter 0505) processed recently and covering the time window from the BOM (beginning of mission) to present, was described. Here after are detailed the main improvements introduced in the L1B Algorithm and the on-going investigations STR on board Swarm Alpha, Bravo and Charlie operate nominally, delivering high-quality pointing data at 1Hz. Moreover, since March 2018 we have the STR instruments on-board the three Swarm spacecraft operating as particle detector (through counting of hotspots). Concerning the STR data quality, a correction model that uses CHU (Camera Head Unit) and Optical Bench temperatures as input is introduced into the computation of the attitude of the Star Tracker (STR) Common Reference Frame (CRF) in order to remove the variation of the CHU boresight with temperature. Long term application outside model interval (i.e., model built using around 2 years of data at the beginning on the mission) show excellent agreement. Moreover, in order to investigate the root cause of CHU boresight variation with temperature, some on- ground tests will be performed. VFM on board Swarm Alpha, Bravo and Charlie operate nominally, delivering high-quality vector magnetic measurements at 50Hz. Significant improvements have been implemented in the Level 1B “VFM” processing algorithms among which the full separation of the pre-flight from the in-flight VFM calibration parameters and the update of the vector data calibration (updated VFM scaling evolution) and disturbance characterization (improved dB_Sun model). It was reported during the workshop that the dB_Sun correction model, currently used in operations, is performing very well. On this disturbance field, we know from tests performed on-ground that thermoelectric currents in the pigtail grounding-wires are responsible for the disturbance seen in-flight. An expert group is working to build a physical based correction model that takes into account all the outcomes coming from these ground tests. It is also confirmed that a correction model is needed not only for the VFM instrument that seems to be disturbed in all the three directions, X, Y and Z but also for the ASM instrument that seems to suffer from the same kind of disturbance but almost exclusively in the Y (east- west) direction. This has little impact on the ASM scalar measurements during nominal flight. However, since this disturbance at the ASM is currently being corrected at the VFM an error that could be as large as 5 nT may be present in the Y (East-West) component of the vector magnetic data. The expert team has already proposed a new correction model for the VFM instrument and this model is under validation. Some first encouraging results are obtained but more work needs to be done.

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ASM on board Swarm Alpha and Bravo operate nominally, delivering high-quality scalar magnetic measurements whereas no ASM operates on Charlie (since 5th November 2014). It is well known that the role of the ASM instruments in the Swarm mission is not only to produce accurate absolute scalar measurements of the Earth’s magnetic Field (1Hz L1b scalar data) but also for providing an absolute reference for calibrating the VFM instruments (at 1 Hz and 50 Hz L1b vector data). While analysing the previous Swarm L1B data (product baseline 03 and 04), the experts have found that the resampling of the ASM data from tASM to exact UTC is removing part of the high frequency content of the ASM data. Thus, new (non-smoothing) cubic B-splines are now used to interpolate the ASM data from tASM to exact UTC in order to retain the full high frequency content of the raw ASM data (essential for observing high-frequency Ionospheric dynamics). As mentioned above, the team is also taking advantage of some periods when Swarm spacecraft was flying not in the nominal direction (i.e., manoeuvres) early in the mission to isolate, parameterize and possibly correct the ASM readings for that part of the perturbation that affects them. The first presented results are very promising but as in the case of the VFM instrument, further investigations are needed. Moreover, from almost the beginning of the mission, the ASM instruments have simultaneously produced vector data (ASM-V) that are independent from the nominal L1b VFM data. An improved (calibration and correction) ASM-V dataset (4 years dataset) was generated and used to produce independent SHA geomagnetic field models. As result, the geomagnetic field models built from recalibrated ASM-V data compare now very well (including the secular variation) with models built in the same way from nominal L1b VFM data, and with other more elaborate models (e.g., CHAOS-6). ESA Swarm Team will distribute this dataset to all the Swarm users as soon as possible. It is worth noticing that there is a growing interest in having the ASM instruments on-board Swarm Alpha and Swarm Bravo set in Burst mode, i.e., scalar measurements at 250 Hz frequency rate, more frequently. In order to test the overall production chain, a first in-flight test was performed on Swarm Alpha, on 25 July 2018 (40 hr duration).

2.3 Electric Field Instruments The third session during the SDQW#8 was dedicated to EFI (Electric Field Instruments), and focussed on the status of both plasma instruments, that are the Langmuir Probe (LP) and Thermal Ion Imager (TII), on the quality of their measurements, validation and calibration based on ground based data and ionospheric models. In addition, a number of studies illustrated potential new Swarm plasma products. LPs on-board Swarm spacecraft acquire scientific valuable data nearly continuously (3 second gaps every 6 hours), having provided, from beginning of operation to present, more than 52000 equator crossings per satellite. No signals of degradation of the instruments have been observed so far. With the last reprocessing, completed on August 2018, a significant improvement in the algorithm for the electron temperature has been implemented: the electron temperature is now obtained from the high gain probe data only, while previously it was computed with a blending algorithm based on the data from both the two probes (low and high gain). This avoids the jumps in the temperature previously observed around the magnetic equator. Moreover, a comparison of Swarm data with incoherent scatter radar has recently demonstrated that the temperature from the high gain probe is also more accurate. Other investigation about LP products focussed on comparison of electron temperature obtained from Swept LP mode (1/128 Hz) with the IRI model and on comparison of data from the two probes. Simulation were also performed and presented to determine the accuracy of currents measured by the Swarm front plate. Since the commissioning phase, it was noted that TII is affected by a degradation of the images, due to the presence of contaminants inside the sensors, most probably due to water vapour. In order to deal with this problem, dedicated meetings with PIs, scientists and Swarm data quality experts held monthly since Summer 2014 (67 meetings to date). Currently, it is adopted the Scrubbing procedure that consists in heating the sensors applying voltages different than nominal, in order to “scrub” away contaminants. This allows to obtain valuable TII scientific data every 3 (Swarm_A), 6 (Swarm_B) or 1 (Swarm_C) orbits per day. The quality of TII data is continuously improved, and the final aim is to restore the continuous acquisition. Several presentations during DQW focussed on verification of TII data. In particular, the latest procedure to calibrate the cross track ion velocity was shown, based on minimization of the velocity at middle geomagnetic latitudes, outside the polar cap. With this procedure, the calibrated TII ion velocity

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shows a good agreement with the Weimer [2005] model. Another investigation compared the Swarm and DMSP cross track ion velocity at middle and low latitude, in order to verify the co-rotation. The two dataset showed comparable accuracy, therefore, a proper verification of Swarm TII data is not feasible based on DMSP data. Another investigation showed a successful method to calibrate the Electric Field measured by TII, based on the comparison of ionospheric conductivities estimated from Swarm using two different methods. Various presentations illustrated innovating approaches to obtain new scientific products from EFI measurements. In particular, the correlation of TII ion velocity with LP electron temperature allows estimating the ion-neutral collision frequency, and therefore, the thermosphere-ionosphere coupling. The along track velocity component, which is currently missing in the last TII products, can now be estimated using both TII and LP measurements. Moreover, the effective ion mass obtained from LP measurements, showed a good statistical agreement with the ion mass provided by IRI model.

2.4 GPS and ACC instruments The accelerometer data processing of Swarm C along-track accelerometer data was described in detail during the fourth session. The processing includes semi-automatic step correction (success rate 80%) and manual step correction (for remaining 20% and occasional false corrections), bias and temperature effects correction, and generation and interpretation of validation reports. On average 19.5 steps/day are perturbing the accelerometer data, which stresses that effort required to rescue the accelerometer data is very high. A new corrected dataset of Swarm C along-track accelerations covering the period from May to November 2016 was positively evaluated by an independent approach and the data was considered to be releasable to the public. Considering that the processing of Swarm C along-track accelerometer data is now progressing faster, the follow-up processing priorities were discussed. The dataset of Swarm C neutral densities derived from GPS receiver and accelerometer data was used for a statistical analysis of gravity waves. The Swarm results show good consistency with earlier results from the CHAMP mission. It should be noted that such an analysis requires accelerometer data, since neutral densities derived only from the GPS receiver data have an insufficient along-track resolution for detection of gravity waves. The GPS receiver data showed that the neutral density at the altitude of Swarm B approaches the inherent noise level since 2016. This means that the density signal is sometime lower than the noise originating from the GPS receiver observations, which results in (physically impossible) negative densities. Recent results show that the same occurs at the altitude of Swarm A and Swarm C since 2018. It is expected that due to the advance towards the solar minimum and the planned orbit raise maneuvers, the signal-to-noise ratio will decrease further, which limits the use of these data products and makes the correction of the accelerometer data even more challenging. The improved modeling of gas-surface interaction was presented together with a high-fidelity geometric model of the Swarm spacecraft. The model allows taking shadowing effects and multiple reflections of particles into account. A key aspect is the energy accommodation coefficient, which effectively scales the drag coefficient and hence the neutral density data, which has implications for the consistency of older datasets with the Swarm dataset in view of data assimilation for creating climatological datasets. The analysis is a powerful tool for investigating the bias related to insufficient knowledge of geometric and thermo-optical properties, which is estimated to be around 30%. The discussion highlighted that a unified energy coefficient for the entire spacecraft is perhaps not optimal due to different surface temperatures. Another improvement was reported for the determination of non-gravitational accelerations from only GPS receiver data. An advanced model of radiation pressure (solar, Earth albedo, infrared) was used to reduce the respective acceleration from the total non-gravitation acceleration, so that the aerodynamic acceleration could be estimated in isolation. First results of this new approach indicate that the non-gravitational accelerations are estimated more accurately. Before the reprocessing of Swarm data in 2018, the RINEX observation files were subject to half-cycle carrier phase ambiguities. After the reprocessing, they were subject to full-cycle carrier phase ambiguities. The latter allows integer ambiguity fixing as part of precise orbit determination. A validation by satellite laser ranging revealed that this improved the accuracy of the reduced dynamic and kinematic orbits by 30%

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and 50%, respectively. Further, it was highlighted that an update of the GPS receiver antenna phase center variation maps is needed for exploiting the full-cycle carrier phase ambiguities to the full extent (the maps change slightly). The Space Weather Atmosphere Model and Indices (SWAMI) project was presented, where the Drag Temperature Model (DTM), which is a semi-empirical model describing the temperature, density, and composition of the Earth’s thermosphere, will be extended and blended into a Model of the Whole Atmosphere (MOWA). It was demonstrated that the scaling of neutral density datasets is of concern for consistency between datasets from different satellite missions. Further, it was highlighted that the Swarm A/C neutral density dataset is the only data source since 2016 above 400 km and below 815 km (altitude of the Stella satellite). In this context, the launch of the GRACE-FO satellite pair in 2018 into an orbit with an altitude of 500 km should be mentioned in view of mission synergies (also see session 9). The Swarm E GAP instrument data is used for the determination of total electron content (TEC) of the ionosphere and radio occultation. First results of precise orbit determination and also attitude determination were presented at the workshop. If it is possible to obtain also non-gravitational accelerations from the GAP instrument data is not yet clear. The first results for the orbits revealed that the reference ephemeris of the Swarm E satellite is subject to km-level errors and that the onboard navigation solution of the GAP instrument has errors with a 3D RMS of 20-25 m and a radial bias of -15 m. It was suggested to check if the GAP instrument applies troposphere/ionosphere corrections and, if so, to turn them off. Further, the first orbit results indicate that a reduced-dynamic orbit at dm-level accuracy should be feasible when GAP data is available and, obviously, lower accuracy when data gaps in GAP data are interpolated. Carrier phase residuals of Swarm E are in the order of 8-10mm (for Swarm A/B/C 5mm), which was attributed to the fact that the Swarm E GPS antennas have no choke ring. The discussion on GAP data availability revealed that a continuous dataset cannot be achieved due to the onboard data handling system of Swarm E. It was predicted that the maximum possible duty cycle of GAP data could be approximately 80%. It was further noted that the GPS antenna accommodation on Swarm E is not optimal. This means that in combination with the absence of a choke ring, multipath effects are of concern, so that large carrier phase errors at low elevations are expected. It was mentioned that the GAP instrument supports an elevation mask, however, with respect to Earth’s horizon instead of the GPS antenna bottom plate since the instrument is a terrestrial receiver. It was suggested to check if a firmware update would support an elevation mask with respect to the GPS antenna horizon. The DISC project for combining gravity field solutions from different processing centers aims at reducing the “analyst noise”. The need for independently processed solutions was highlighted, where independency extends to the kinematic orbits from which the gravity fields are retrieved. The gravity field models from Swarm data show a positive correlation to GRACE gravity field models up to degree and order 12−15. A time series of global ocean mass from Swarm GPS receiver data compares well to the time series based on GRACE data. Therefore, Swarm data is capable of filling the gap between the GRACE and GRACE-FO missions, with obvious limitations due to the lower spatial resolution. The “dipole equator artifacts” in Swarm gravity field models were extensively discussed. Combinations of various metrics based on TEC were explored for down-weighting problematic observations, which showed that it is possible to mitigate the dipole equator artifacts to a large extent. It was suggested to analyze the GPS receiver tracking loop transfer function in an attempt to find a deterministic correction for the dipole equator artifacts. Further, it was suggested using the RMS in a sliding window for weighting of observations in the gravity field retrieval.

2.5 Advanced products for Internal fields This fifth session mainly dealt with new data processing and modelling strategies facilitated by data, and internal (core) field changes. This session included 3 presentations on core field and its temporal changes, and core surface flow, 2 presentations on mantle electrical conductivity, 1 presentation on the out-of-cycle World Magnetic Map update and 1 presentation on the 3D Earth project. Concerning field models at short timescales, Lesur et al. propose to develop a sequential approach, with realistic priors on temporal and spatial variations/correlations to produce a sequence of monthly models.

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The presented results show discrepancy when compared to the Gillet et al. (2015) model, the latter inferring torsional waves with period of ~6 years which are not present in Rapp and Lesur (2018). Finlay et al then presented results on secular acceleration pulses with duration of the order of 1-2 years, spatially localized; associated with – unpredictable – geomagnetic ‘jerks’ or impulses. The developed tools for studying them include temporally dependent spherical harmonic models; point-by-point estimates of the core surface field and its time derivatives (SOLA and Virtual Observatory methods). Such approaches allow to understand origins of features similar to those observed from geodynamo simulations The Whaler et al presentation focused on the utility of Virtual Observatory (VO) secular variation estimates for core flow modelling. First version of monthly VO time series estimates appear to be biased, probably due to data gaps and local time effects. DTU is also producing 4-monthly VOs with stringent data selection criteria, use data sums and differences, reduced to single point assuming cubic spatial potential dependence. The modelling residuals are much smaller and show greatly reduced bias. Very little core flow temporal variations are required to explain the observed secular variation. The VO gradient secular variation data have better core flow resolution. Velimsky et al then reported on mantle conductivity time domain approaches, estimating both 1D and 3D variations, which show respectively best resolution at 500-1500 km depth and persistence of features mimicking signatures in mantle tomography models. Grayver el al presented alternative approaches to define the optimal (minimal) set of field coefficients required to specify the inducing field, by ranking them by decreasing importance and determining the necessary number. This number varies according to the external field activity, and is different for satellite and ground–based data. The World Magnetic Model presented by Brown et al. is currently out of specification owing to geomagnetic jerks violating the linear secular variation assumption. The prompt availability of dedicated satellite data has therefore been crucial to produce an accurate update of this model. The 3D Earth solid model presented by Ebbing et al uses Swarm data to investigate depth to Curie isotherm at regional scale and then compare it to the lithosphere thickness. Such model requires a number of assumptions (only magnetite, magnetization purely induced, …) and incorporate multiple data sources to investigate crustal and mantle structure and seismic radial anisotropy. However, iterating from a simple model led to loss of key features such as mid-ocean ridges. Geologically useful models therefore require aeromagnetic as well as high-resolution satellite magnetic data.

2.6 Advanced products for External fields The session on Advanced Products for external field included several contributions on the benefit of high- level approaches applied on Swarm observations. The topics of the session can be roughly categorized under three themes, i) parametrizing geospace interactions with empirical models, ii) harvesting new measurements and data products, and iii) new methodologies for advanced data analysis. Laundal et al. first presented an empirical model of high-latitude ionospheric currents derived from Swarm and CHAMP magnetic field data. Combination with the Weimer-model of electric field allowed an estimation of Joule heating. The global estimates can be validated by MHD simulations or in regional scales by combined Swarm magnetic and electric field measurements as suggested by Marghitu et al. To support such cross comparisons it would be valuable to update the Swarm cross-track velocity data archive with a quality flag characterizing the intensity of along-track velocities. Chulliat et al., proposed to expand the input parameter set of the L2 empirical model of ionospheric currents at low and mid latitudes by solar cycle. Yamazaki et al. suggested combining Swarm Sq-current estimates with physical models and then deriving the thermospheric wind that has generated the Sq- pattern. Brown et al. presented a new fast-track approach for magnetospheric field modelling and Stolle et al. introduced an empirical model of the occurrence rate of post-sunset low latitude plasma depletions at LEO-satellite altitudes. Skone et al. discussed opportunities to use Swarm data in ionospheric scintillation and tomography studies. First results on the climatology of Total Electron Content (TEC), Rate of TEC (ROT) and ROT index (ROTI) based on Swarm and GOCE data was presented by Kervalishvili et al. The IPIR index introduced by Miloch

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et al uses an extensive set of data products from Swarm GPS and LP to describe time and amplitude variations in plasma density at all latitudes. Clausen et al. presented an innovative inversion technique to estimate local in situ plasma density from integrated TEC observations at one satellite. All these data products will be useful in global multi-instrumental ionospheric storm studies along the lines presented by Zakharenkova, et al. To enhance their relevance in space weather activities these investigations call for a detailed description on the linkage of electron density and TEC fluctuation rates to GNSS phase and amplitude scintillations. Kauristie et al. presented approaches to determine peak and boundaries of the polar electrojet derived from Swarm magnetic data and Xiong et al. discussed a model of the auroral boundaries derived from Swarm Field-Aligned Current (FAC) data. High frequency magnetic data at 50Hz and/or 250Hz were used to detect whistlers initiated by tropospheric lightning (Coïsson et al), and Pc1 and Pc3 pulsations (Balasis et al.), while Alberti et al. applied different mathematical approaches to characterize spatial properties of the Sq and magnetospheric ring current signatures. Blagau et al., Dunlop et al. and Yang et al. discussed different methods for deriving FACs, current sheet tilts and FAC cross-correlations from multiple satellite magnetic field observations. A toolbox with manuals would facilitate wider usage of these advanced methodologies in case studies. Jørgensen et al. introduced a fundamentally new measurement parameter of the mission, which is the detection rate of intrusion of high energetic particles at the star cameras. The detection rate will be soon released as a new Swarm official data product. The presentations of this session demonstrated the continued interests of researchers to find new ways to use Swarm data in characterizing space – atmosphere interactions. This encourages further investments for extracting refined parameters from Swarm observations that together with physics based modelling have high benefit to quantify a wide variety of processes in our space environment.

2.7 Swarm –CSES Synergies Session 7 was entirely devoted to report from the scientific and technical teams involved in the processing, early evaluation and validation of the data produced by the Chinese Seismo-Electromagnetic Satellite (CSES) launched on February 2, 2018 on a sun-synchronous circular orbit (507 km altitude, 97° inclination, LT descending node 14:00). The main goal of this mission is to investigate the possibility of detecting electromagnetic and ionospheric signals acting as precursors of seismic event, as well as possible co-seismic signals. Its payload, however, appears to also be suited for many other Swarm-related science investigations. Seven invited talks were therefore given, with the overarching goal of presenting the current status of the mission, payload, ground segment, and early data evaluation activities to the Swarm science community, so that the potential for Swarm-CSES synergies could be assessed. A first presentation, by J. Zhang and his colleagues of the Data Quality Evaluation System (DQES), provided an overview of the satellite and its payload, consisting of a GNSS Occultation Receiver (GRO), a Plasma Analyzer Package (PAP), a Langmuir probe (LAP), a High Precision Magnetometer (HPM, combining an absolute CDSM scalar magnetometer and two flux gate magnetometers, FGM1 and FGM2), a high Energetic Particle Package (HEPP) and Detector (HEPD), a search coil magnetometer (SCM), an Electric Field Detector (EFD) and a Tri-Band Beacon (TBB), either deployed as antennas, on booms or sitting on the cubic shaped body of the satellite. A set of three star sensors sitting on the body of the satellite, is completing this payload. This presentation also presented the CSES ground segment organization, the various data products that will be made available from CSES at various levels (from L00 to L04), the format of the data produced and, finally the tasks specifically assigned to the DQES itself (data cross-validation, ground data verification, data quality evaluation, etc.). A second presentation, by W. Magnes and colleagues, focussed on the presentation and status of the scalar magnetometer (CDSM). The principle of this instrument was explained and it was convincingly shown that the instrument was operating nominally. The preliminary data compared encouragingly well with geomagnetic field models built from the Swarm mission, even though issues about interferences with the satellite (and other instruments) still need to be investigated (not an unusual situation during commissioning).

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The third presentation, by B. Cheng and colleagues, provided complementary details about the rest of the HPM payload, with some focus on the behaviour and data provided by the two flux gate magnetometers (FGM1 and FGM2). Details about ground calibration activities were described, and vector data compared to predictions from geomagnetic field models built from the Swarm mission. It was shown that FGM magnetometers are operating essentially as expected, providing high frequency data with low noise and high resolution, though more work is needed to obtain a fully consistent set of data by the HPM payload as a whole. These tests also revealed a limited attitude accuracy of 0.1° of the vector field when reconstructed in the North East Centre coordinate system, attributed to the fact that the HPM suite of instruments is distributed on a not-so-stiff boom away from the body of the satellite, where the set of Star Sensors is located The fourth presentation, by Y. Yang and X. Shen, provided complementary information about the ground segment, also giving details about the data format and the website, which will be available to users, in future, to access the data. Examples of plots from so-called Level 02 data (calibrated and quality-checked that most users will be able to access) were shown, also illustrating data from the HPM, and also from the SCM, EFD, LAP, PAP, HEP, GRO, TBB payloads. Worth being noted is the fact that data are only acquired between 65°S and 65°N, and stored in files containing data from only one orbit leg (ascending, or descending) at a time. Examples of the behaviour of the corresponding quantities were also used to illustrate the response of the ionosphere detected by CSES during a geomagnetic storm and highlight the type of Swarm-like investigations CSES could help achieve. The fifth presentation, by B. Zhou and colleagues, provided additional information about the magnetic data processing method used by the CSES team, with special emphasis on the way the FGM magnetometers had been calibrated against the HPM (scaling factors, angles, offsets), and their crosstalk addressed. They also showed direct comparisons of CSES vector field data (presumably L02 level) against Swarm Bravo vector data (L1b in ESA’s definition), at 11 000 cross points between May 19 and 24, 2018, using a Swarm magnetic field model for geographical adjustment. These comparisons led to very interesting results, revealing an upper bound estimate of 0.05° error in vector field attitude restitution (when considering all data, and of even less when considering only data from quieter low latitudes). These numbers are more encouraging than those provided by Cheng and colleagues (recall third presentation above). The sixth presentation, by X. Wang, looked into the quality of electron density data obtained from the LAP and GRO payloads. Electron density maps for various local time and geomagnetic conditions were compared with similar maps built from Swarm Alpha LP electron density data, revealing similar general distributions, but also revealing discrepancies between the information provided by the LAP and the GRO payloads, and between the information provided by the LAP and the Swarm Alpha LP (a factor 10). As pointed out by the author, further investigations are clearly still needed. The seventh presentation, by Z. Li and collaborators, finally discussed the possibility of using CSES electron information (from the LAP) and ion information (from the PAP) for detecting abnormal behaviours before and after earthquakes, using a dedicated processing scheme, based on experience derived from the Demeter mission. Overall, it thus appeared from these presentations that CSES is currently experiencing a promising commissioning phase, all of its payload being in good shape, providing data, many of which are already of good quality. Opportunities for synergies between CSES and Swarm investigations appear to be plentiful, and the CSES expert team is encouraged to collaborate with their colleagues from the Swarm expert team for further cross-calibration and validation activities, with the ultimate goal of further improving the quality of the data produced. Collaborations for such endeavour are encouraged by ESA and could be supported through the ESA/Chinese “Dragon” program (dragon4.esa.int). Such activities would clearly benefit both missions, the data of which could next widely be used by the science community. It is highly recommended that CSES experts share data at an appropriate level with the relevant Swarm experts in order to start such activities as soon as possible.

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2.8 Swarm - Echo The Canada’s Cassiope satellite has joined ESA’s Swarm Alpha, Bravo and Charlie satellites as Echo on 22 February 2018. Swarm Echo carries e-POP (Enhanced Polar Outflow Probe) instrument package, which delivers data that complements data provided by Swarm Alpha, Bravo and Charlie. Enno gave a summary of the status and health of the spacecraft and of the e-POP payload. Cassiope itself is still quite healthy with all major spacecraft subsystems (command and data handling unit, power control unit, battery, solar panels, receivers, transmitter, attitude control, and thermal control) all still operating nominally with no fail-overs to any of the redundant units. The only real failure of note was the loss of reaction wheel #4, but as this was the redundant wheel, normal flight attitude control has been maintained. Although the orbit has decayed, as with the rest of the Swarm constellation, it has been at a much slower rate than was expected before launch. Given the current level of solar activity, it is now expected that Cassiope will not re-enter until at least late 2021. The e-POP payload is also operating well, especially the MGF and GAP instruments which are of the instruments of most interest to the Swarm community at this point in time. The priority at the e-POP Science Centre (eSOC) has been to maximise the global coverage of the MGF and GAP instruments and the results have been encouraging. With the formation of the magnetic and GPS working groups, excellent feedback has been provided both for science planning to fine tune the coverage and maximise the synergy with the rest of the Swarm instruments, as well as for the MGF and GAP PI’s to tailor their data products to be compatible with the Swarm magnetic and GPS data for greater utility of use by the greater science teams. Enno concluded by inviting members of the Swarm Science Team to get actively involved with both the planning of novel collaborative experiments using the e-POP payload, possibly as Scientist-in-Charge, and to network with e-POP investigators to leverage their knowledge of the instruments and the dataset to allow for a faster and deeper understanding from which to work together with. The session on Swarm – Echo included a contribution (presented by White) about how and where it is possible to get information and data from the following instruments: MGF (magnetic field), RRI (radio receiver), IRM (imaging rapid-scanning ion mass spectrometer), NMS (neutral mass and velocity spectrometer), FAI (fast auroral imager), SEI (suprathermal electron imager), CERTO (coherent electromagnetic radio tomography) and GAP (GPS attitude, positioning and profiling experiment). All information about e-POP data including updates is available at https://epop.phys.ucalgary.ca and data is accessible through the Telemetry Explorer (eTEx) and/or Data Explorer (eDEx) tools. The other seven contributions presented in the Swarm – Echo session included information on e-POP data calibration, validation and scientific results. Miles et al. presented updates on magnetic field data products and operational/experimental processors: both MGF sensors continue to operate nominally and preliminary data feed to Swarm DISC (*.lv2Cal) is operational; the loss of one reaction wheel (from 4 to 3) has degraded 10 sps data; post-processed attitude correction (there are known issues with attitude solution and control) is promising but not yet operational. Rother presented preliminary results from established processing work-frame on MGF data calibration. Already on this early stage with first tests on lv2 data some inconsistencies were found and reported (work in progress). It was documented that rough or inappropriately filtered attitudes will always affect the calibrated vectors in the NEC system. Comparison with already existing e-POP lv3 data is on-going. Perry reported on validation status of radio receiver instrument and data processing. RRI's amplitude could possibly be validated using ground-based transmitter. A new model of SuperDARN Saskatoon's radiation pattern, propagated through IRI ionosphere has been created and preliminary results show good agreement between power measured by RRI and model predictions (work in progress). Final RRI data products are available as the lv1 HDF5 files that also include a spacecraft ephemeris data. James et al. gave a comprehensive review of the past and current research on RRI studies of propagation and scattering with ground radars and ionospheric heaters coordinated with RRI. Also, the possible future research was suggested on whistler-mode science (e.g., near zone of navy VLF transmitters, radiation from demonstration and science experiments) and objectives including medium and high frequency (e.g., observations in situ of EM emissions seen on the ground, wave emissions of a rocket). Yau et al. reported on data processing including new product software development and validation status of imaging rapid-scanning ion mass spectrometer instrument. Level-1 data and plots are produced and

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available for download at https://epop-data.phys.ucalgary.ca. Level-2 data is under final testing phase and planned to be realised by the end of 2018. The routine software development for the higher-level products (plasma parameters) is work in progress activity. IRM continues normal and routine operation in a survey mode (1 measurement cycle is equal to 12 measurements) with an increased operation duty cycle at all latitudes and altitudes since mid-2017. Howarth presented developments on calibration and data processing activities on fast auroral imager instrument. FAI instrument is operating when in eclipse and within 400 km of Swarm Alpha, Bravo and Charlie and in “campaign mode” when eclipse periods are abundant at high latitude. Level-1 data product format is being changed to HDF5 format (work in progress) and Level-2 data product now includes calibration, the magnetic footprint of the spacecraft and process position and attitude information to project pixels to auroral altitude. Shen et al. reported on data calibration and new scientific results of suprathermal electron imager instrument. New features in SEI electron data from the gain correction map obtained from secondary electron images. Then GLOW model is used to calibrate and validate the absolute energy flux for electrons larger than 100 eV. Also the first direct observations of transverse electron heating in the ionospheric altitudes, such heating occurs on a time scale of 0.1 seconds was presented. The contributions of the Swarm – Echo session have shown that there is a good and visible progress in all presented products and promising results should be expected from on-going calibration and scientific validation activities. New scientific findings and results have been also presented and supporting data and plots are available at https://epop.phys.ucalgary.ca. Swarm Echo data synchronisation to ESA Swarm dissemination server is in progress and it was agreed that after validation activities are finished the data format of the new MAG and GAP Swarm Echo products will be updated to match Swarm L1b and L2 data product formats. Also, it was suggested that one person from the Swarm team should be chosen to coordinate these activities including data calibration and scientific validation.

2.9 Multi-mission synergies Session 9 was a session in which the contributions were dealing with complementary satellite data to Swarm in various application areas. The first group of three presentations focussed on the use of magnetometers from DMSP and platform magnetometers from non-magnetic field satellites like CryoSat and GOCE to complement Swarm magnetic field analysis. Patrick Alken presented the first contribution on “Core field modelling with a combined dataset from CHAMP, DMSP and Swarm”. Nils Olsen presented the second one on “CryoSat magnetometer data calibration”. Claudia Stolle presented the third one on “CryoSat and GOCE magnetometer calibration and applications for ionospheric currents”. The intention with the data from DMSP is to try to bridge the gap between CHAMP and Swarm. The magnetometer data from DMSP need careful attitude correction, data editing for jumps and calibration. This is achieved by using CHAOS-6 as reference. The first results are promising and a combination of CHAMP, DMSP, Swarm and INTERMAGNET is proposed. For both CryoSat and GOCE the AOCS fluxgate (3x) magnetometers were used. These needed corrections for temperature (includes orbital) and magneto torquer activation and calibration. The procedure also relies on CHAOS-6 as prior. The results are consistent with CHAOS-6 and external signals like FAC and MMA. The GOCE results seem to have a slightly higher noise floor. Eelco Doornbos presented the fourth contribution on the “Observation capabilities of GOCE and GRACE related to the Swarm mission objectives”. He focussed on the GOCE and GRACE potential product suite useful for thermospheric modelling. For GOCE neutral density and horizontal (cross) wind products are available whereas deorbit phase thermosphere data, vertical neutral winds, TEC and ROTI (topside) and magnetic field data are in development. For GRACE neutral density (problematic in later years) and winds (problematic), electron density between satellites, TEC and ROTI (topside) are all published; the AOCS magnetometer capability is not yet analysed. The next two contributions focussed on multi-satellite (primarily TEC) for modelling and space weather. Yurii Cherniak presented the “Application of the multi-satellites observations for ionospheric climatology and space weather research”. Ludger Scherliess presented a “Comparison of TEC specifications obtained from a data assimilation model with Swarm observations”. The multi-satellite TEC shows discrepancies

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with models (Nequick, IRI): The major source of the model-data discrepancies in the EC/TEC domain comes from the topside ionosphere/plasmasphere system. The most problematic altitude region for the model/data differences was found to be within the altitudinal range of ~500-2000 km. Multi-mission TEC combinations are suited for studying climatology and events like TIDs, bubbles, etc. GIAM (physics based assimilation model) comparisons with GOCE data, which were not assimilated, showed reasonably good agreement indicating the potential of the model. Similar comparisons can be done for various Swarm observations in the future, and consequently data can be assimilated. A further developed model like this is in line with ESA’s 4D-Ionosphere science meeting ideas. Junga Hwang presented the last contribution in this session on “Similarities and differences between Swarm and SNIPE constellation (Small scale magNetospheric and Ionospheric Plasma Experiments)”. SNIPE is Korean initiative to launch four nanosatellites in 2020 as small-scale magnetospheric and ionospheric plasma experiment. The targets are to study spatial scale and energy dispersion of electron microbursts, temporal and spatial variations of plasma trough during magnetic storms, temporal and spatial variations of electron density and temperature in polar cap patches, measuring length of coherence for bubbles/blobs, observing EMIC waves at the top of ionosphere, and large amplitude disturbance of field aligned currents. The satellites carry a Langmuir Probe, magnetometer and GPS and fly in a sun- synchronous orbit of 550 km. This offers the potential for exploiting the Swarm and SNIPE synergy.

2.10 Swarm & SPACE 4.oI The session on Swarm and Space 4.0i was split into three subtopics: 1) innovative future mission plans, 2) application of machine learning techniques to Swarm data, and 3) improvements in access to data, tools and information. The discussion on the presentations was partly held during the session summary timeslot on the next day. A summary of the presentations and discussions are provided here below. At the start of the session, future mission concepts were presented. The first was an update on NanoMagSat (informally named Swarm Delta), provided by Gauthier Hulot. The presentation contained details regarding recent further development of the miniaturised ASM instrument. The current status of the project is that Phase O studies have been finalised, and further work is ongoing, with Phase A recommended by the CNES scientific board, and with strong support from the science community. Next, Roger Haagmans gave an introduction on the three proposals submitted for the EE10 call, that were selected for phase 0 studies: STEREOID, G-CLASS: H2O and Daedalus. The call for applications for the Mission Advisory Group of these missions has recently opened. Guram Kervalishvili, co-proposer of Daedalus, subsequently gave further details on that mission. Daedalus is a concept to make a full range of in-situ measurements of the thermosphere-ionosphere, from an elliptical orbit with a 150 km perigee, with deep dives and subsatellites released to measure in the 100-150 km range. Processes like Joule heating, particle precipitation, gravity wave interactions and cooling are very important in this altitude range. They determine the conditions in the thermosphere-ionosphere above. The presentation of the mission concept was received positively by the Swarm community. Although the mission concept was still very new to most participants, the possibility of providing mission advice (lessons learned) from the Swarm community was raised. In addition, suggestions were made to investigate whether the science objectives of the mission could be broadened, and if temporal sampling rates could be increased, particularly for the magnetic and electric field measurements. The next block of session 10 contained three presentations on the application of machine learning techniques to processing of Swarm data. These included talks on modeling along-track ISL electron density data from Demeter, in preparation for application to CSES (Xiuying Wang), identifying magnetic field anomalies possibly related to seismic activity in Swarm data (Yaxin Bi), and identifying ULF waves in Swarm data, trained using CHAMP data (Constantinos Papadimitriou). In the last block of the session, more details were provided on the Swarm ViRES Virtual Research Environment (Gabriela Costa, Luca Mariani), which will soon become available. The viresclient Python package, presented by Ashley Smith, should become an integral part of this environment, making it easy to access and manipulate Swarm data with just a few lines of code, in a Jupyter notebook environment. The ability to share such notebooks is likely to make it much easier to create tutorials for new users and facilitate collaborations.

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The final presentation, again by Guram Kervalishvili, was on future plans for the ESA Swarm website. The Earth Explorer websites are undergoing a complete redesign at the moment, and Swarm will serve as an early example. So feedback, both on the current website and on the new one, when it becomes available, is welcomed.

2.11 Summary and Conclusions The 8th Swarm DQW was a great success and confirmed that the Swarm constellation and associated payload systems perform very well. The quality and overall operational production of Swarm science products are excellent and fulfil the need of a wide spectrum of multi-thematic scientific users. Since the last Swarm DQW, new versions of the Swarm processing baseline have been successfully deployed in operation. The 8th Swarm DQW gave an unique opportunity to brainstorm on future Swarm scientific challenges, orbit changes, next products and multi-disciplinary applications as well as to present innovative Machine-learning approaches and Multi mission synergy. All these aspects were highlighted and thoughtfully discussed during the last session of the workshop, which also allowed listening and compiling key recommendations from the Swarm technical experts and scientific users. These recommendations are listed in section 3 of this Summary and Recommendation report and will be extensively used to draft the mean-term roadmap for future Swarm-based activities until the next Swarm DQW which will be held in Prague (Czech Republic) in mid-September 2019.

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3 RECOMMANDATIONS

The following table compile most of recommendations expressed by the Swarm DQW#8 participants:

[Rec. 1] Adapt the L1BOP in order to be able to process L1B MAG Magnetic Field data with ASMxBUR_0_ data as input [Rec. 2] Run ASM on Swarm Alpha and Swarm Bravo in Burst mode more frequently (two weeks sessions). [Rec. 3] Generate new Swarm Product from ASM 250 Hz Burst mode science data. [Rec. 4] Produce a new Swarm STR L1B “particle flux” product [Rec. 5] Implement a Time-jitter correction in the MAGNET processor to remove systematic spikes in ASM power spectrum [Rec. 6] Test the improvement that can be obtained by the use of POD rather than MODx_SC_1B as input positions for MAGx_.._1B [Rec. 7] Use the ASM correction model to investigate impacts on field modelling (external fields).

[Rec. 8] Implement a new firmware to adopt an updated version of the Electric Field TII automatic gain control, and to download TII images at higher frequencies (16 Hz). During such high frequency TII

acquisitions, the number of pixels can be reduced to 32, instead of 64, in order to limit telemetry problems. [Rec. 9] Implement new tests for LP bias, with higher voltages (+5V), and release new cross-track velocity dataset with latest improved calibration. [Rec. 10] Define a new e-POP science mode in order to collect data during conjunctions with Swarm that would allow cross- calibration of cross track plasma velocity between the two spacecraft.

[Rec. 11] Release to users the Swarm C along-track accelerations GPS and ACC ACC data covering the period from May to November 2016 [Rec. 12] Continue to correct Swarm C along-track accelerometer data. Focus next on Swarm C cross-track accelerometer data of the second half of 2014 (motivations: large signals at beginning of mission; no large manoeuvres; Swarm C at lower altitude; 1 Hz GPS receiver data available). [Rec. 13] Improve the flagging and daily quality index of the ACCxCAL data products. [Rec. 14] Implement geophysical meaningful sanity checks based on presence of gravity waves (statistics with respect to latitude, local time, solar and geomagnetic activity, season, plasma bubbles, day/night side, etc.) that help to assess the quality of ACCxCAL data products before release.

[Rec. 15] Exploit integer ambiguity fixing when determining the non- A/B/C GPS gravitational acceleration from GPS receiver data.

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[Rec. 16] Maximize the duty cycle of the GAP-A instrument; noting that E GAP one receiver at a 0.1 Hz data rate is sufficient. [Rec. 17] Make star tracker data available and try to collect star tracker data when GAP data is collected, noting accurate spacecraft attitude data is needed for macro models (radiation pressure modelling, etc.). [Rec. 18] Collect GAP-A data once per orbit, preferably at low altitudes (high drag signal) and also some at apogee (constrains orbit). [Rec. 19] Avoid too much segmentation of GAP-A data (ambiguity fixing, etc.) and data gaps longer than one orbit (accuracy gets much worse for long interpolations). [Rec. 20] Determine the GPS antenna phase center location with respect to the spacecraft CoM (from documentation, verify with in-flight data), which should be used conventionally by all groups performing precise orbit determination for Swarm E. [Rec. 21] Determine GPS antenna phase center variations with respect to the antenna phase center location for Swarm E, potentially supported by dedicated campaigns GPS antenna calibration. [Rec. 22] Focus first on precise orbit determination for Swarm E and assess the feasibility of the determination of neutral density at a later stage.

[Rec. 23] Generate and distribute Swarm-based VO products High level product (internal field) [Rec. 24] Develop new data processing/modelling approaches using Swarm data to get better mantle conductivity models and

understanding of core dynamics on sub-decadal timescale [Rec. 25] Justify rationale for 3D Earth approach using Swarm data

[Rec. 26] Update the Swarm cross-track velocity data archive with a High level product (external field) quality flag characterizing the intensity of along-track velocities [Rec. 27] Improve the description on the linkage of electron density and TEC fluctuation rates to GNSS phase and amplitude scintillations to further enhance the use of Swarm for space weather applications [Rec. 28] Develop a well-documented toolbox to facilitate wider usage of innovative methods for Swarm-based FAC determinations.

[Rec. 29] Foster collaboration between CSES and Swarm experts team Swarm - CSES Synergies for cross-calibration and validation activities, [Rec. 30] Make available appropriate level of CSES data to Swarm experts for starting such activities to as soon as possible.

[Rec. 31] Update data format of new MAG and GAP Swarm Echo Swarm - Echo products to better match with Swarm L1b and L2 data product formats [Rec. 32] Coordinate Swarm Echo and Swarm A/B/C activities regarding data cross-calibration and scientific validation

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[Rec. 33] Structure a “Magnetometer calibration expert group” and Swarm and Multi-mission organise a workshop on “Multi-mission data calibration and Synergies application” (about 6 month after the SDQW#8) for identification and coordination of the multi-mission potential and corresponding formulation of needs and procedures. [Rec. 34] Prepare and provide CryoSat and Goce L1B data to the scientific community, consisting in daily CDF files (time, position, calibrated BFGM, STR data, BNEC, flags, …) before Living Planet (May 2019) [Rec. 35] Make a peer-review publication describing data product and calibration process, [Rec. 36] Use CryoSat-2 dataset for gap between CHAMP and Swarm [Rec. 37] Use GOCE, GRACE, CryoSat-2 and in a joint modelling, calibration, alignment process with Swarm and CHAMP for consistent long term modelling . [Rec. 38] Enhance the potential synergy between Swarm and GOCE thermosphere - ionosphere data. [Rec. 39] Enhance the potential synergy between Swarm and GRACE(- FO) and make accessible well-validated and documented products, with similar standards as for Swarm and GOCE. [Rec. 40] Foster cooperation and exchange experience between ACC data processing experts from GRACE-FO & Swarm missions [Rec. 41] Develop multi-mission, consistent, reliable and well-calibrate multi-mission datasets to address key scientific challenges related to upper atmosphere “climate” trend analysis, studies of longer term secular variation vs solar cycle effects, quantification of energy transports by waves and other phenomena.

[Rec. 42] Provide lessons learned from the Swarm community to the Swarm and SPACE4.0I Daedalus MAG [Rec. 43] Investigate whether the science objectives of the Daedalus mission could be broadened, and if temporal sampling rates could be increased [Rec. 44] Enhance the use of Machine Learning / AI methods applied to emerging Swarm Data applications [Rec. 45] Make easier the access / manipulation of Swarm data and facilitate collaborations via the development of Virtual Research Environment [Rec. 46] Redesign and Improve the content of the Swarm web site to make it fully align with the scientific community expectations

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APPENDIX I - SWARM DQW#8 REGISTRED PARTICIPANTS

First Name Last Name Organization Mioara Mandea Cnes Giuseppe Ottavianelli Esa Roberta Tozzi Istituto Nazionale di Geofisica e Vulcanologia Alexey Kuvshinov Eth Zurich Thomas Usbeck Airbus Defence and Space GmbH Berta Hoyos Esa Kamil Tarenko GMV Poland Krzysztof Zawada GMV Pepa Brazal Gmv Martyna Romanowska GMV Innovating Solutions Ignacio Clerigo Esa Roger Haagmans ESA Mike Wenkel Perspecta Inc USA Livia D'Alba ESA-Esrin Maria Eugenia Mazzocato Serco Heike Peter Positim UG Philippe Pacholczyk Cnes Luca Mariani Serco Paola De Michelis Istituto Nazionale di Geofisica e Vulcanologia - INGV Fabio Giannattasio Istituto Nazionale di Geofisica e Vulcanologia Poul Erik Holmdahl Olsen DTU Gabriella Costa Esa Franz Zangerl Ruag Giulia Vinicola Nikal Fm Srl Hermann Opgenoorth Swedish Institute Of Space Physics Thomas Nilsson Swedish Institute of Space Physics Lubica Valentova Department of Geophysics, Charles University Jens K. Jensen Dtu Space Andy Jackson Eth Zurich Angelo De Santis Istituto Nazionale Di Geofisica E Vulcanologia Gianfranco Cianchini Istituto Nazionale Di Geofisica e Vulcanologia Perrone Loredana Istituto Nazionale Di Geofisica E Vulcanologia Line Drube DTU Space Saioa Arquero Campuzano Istituto Nazionale Di Geofisica E Vulcanologia Christian Siemes RHEA for ESA - European Space Agency Georgios Balasis National Observatory of Athens Eelco Doornbos Delft University of Technology Johnathan Burchill University Of Calgary Matthias Foerster GFZ German Research Centre for Geosciences Jaeheung Park Korea Astronomy And Space Science Institute Christina Lück University of Bonn Chris Finlay Dtu Space Pieter Visser Delft University of Technology, Faculty of Aerospace Engineering Antonio de la Fuente ESA Alexei Kouznetsov University Of Calgary Page 22/35

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Nils Olsen Dtu Space - Technical University Of Denmark Hauke Thamm Airbus Defence and Space Le Ren Institut Für Erdmessung (ife), Leibniz Universität Hannover Sean Bruinsma Cnes, Space Geodesy Office Jörg Ebbing Kiel University Jakub Velímský Charles University, Prague Jan Miedzik Gmv Poland Lucas Schreiter Astronomical Institute University Of Bern Daniel Arnold Astronomical Institute, University Of Bern Kathy Whaler University Of Edinburgh Lars Tøffner-clausen Dtu Space Octav Marghitu Institute for Space Sciences, Bucharest Junga Hwang Korea Astronomy And Space Science Institute Igino Coco Istituto Nazionale di Geofisica e Vulcanologia Malcolm Dunlop RAL (ukri-stfc) Richard Marchand University Of Alberta Oliver Montenbruck DLR/GSOC Arnaud Chulliat Univ. Colorado Boulder & NOAA/NCEI Hyanpyo Kim Korea Astronomy And Space Science Institute Yanyan Yang Institute Of Crustal Dynamics, China Earthquake Administration Xiuying Wang Institute Of Crustal Dynamics, Cea Xuhui Shen The Institute Of Crustal Dynamics, China Earthquake Administration Raffaella D'Amicis ESA Bingjun Cheng National Space Science Center, Chinese Academy of Sciences Bin Zhou National Space Science Center, Chinese Academy Of Sciences Constantinos Papadimitriou National Observatory Of Athens Adrian Blagau Institute for Space Sciences, Romania Ludger Scherliess Utah State University Martin Rother GFZ Potsdam Patrick Alken University Of Colorado At Boulder Pierdavide Coïsson IPGP Guram Kervalishvili GFZ German Research Centre For Geosciences Levan Lomidze University Of Calgary Gauthier Hulot IPGP Claudia Stolle GFZ Potsdam Pierre Vigneron IPGP Vincent Lesur IPGP William Brown British Geological Survey Wojciech Miloch University Of Oslo Ales Bezdek Astronomical Institute, Czech Academy Of Sciences Yaxin Bi Ulster University Alexander Grayver Eth Zurich Matija Herceg Dtu Space Juan Rodriguez-Zuluaga GFZ Potsdam Peter Brauer Dtu Space

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Stephan Buchert Swedish Institute Of Space Physics Ewa Slominska Obsee Kirsti Kauristie Finnish Meteorological Institute Sergiy Svitlov Institut Für Erdmessung (ife), Leibniz Universität Hannover Susan Skone University of Calgary Günther March Delft University Of Technology Jose Van den IJssel Delft University Of Technology Chao Xiong GFZ German Research Centre For Geosciences Enkelejda Qamili ESA Lorenzo Trenchi ESA Andrew Yau University of Calgary Christopher Watson University Corporation For Atmospheric Research Greg Enno Dept. Physics and Astronomy, University of Calgary Gareth Perry University Of Calgary Gordon James Natural Resources Canada Andrew Howarth University of Calgary Andrew White University Of Calgary David Miles University Of Iowa Yangyang Shen University Of Calgary Karl Laundal Birkeland Centre For Space Science, University In Bergen Jing Zhang Academy Of Opto-electronics, Chineses Academy Of Sciences Xiaohui Li Academy Of Opto-electronics, Chinese Academy Of Sciences Rune Floberghagen European Space Agency Serenella Di Betta ESOC Martin Pačes EOX IT Services, GmbH Yosuke Yamazaki Gfz Potsdam Tommaso Alberti Inaf-istituto Di Astrofisica E Planetologia Spaziali Ziyang Li Academy Of Opto-electronics, Chinese Academy Of Sciences Detlef Sieg ESA/ESOC Ashley Smith University Of Edinburgh Federica Poggio Istituto Nazionale di Geofisica e Vulcanologia Jose M G Merayo DTU Space Cosmic Program Office, University Corporation For Atmospheric Iurii Cherniak Research (UCAR) Irina Zakharenkova SRRC, UWM Lasse Clausen University Of Oslo John Leif Joergensen Dtu-space Werner Magnes Austrian Academy of Sciences Vladimir Truhlik Institute of Atmospheric Physics, CAS Michael C Paniccia NGA Jerome Bouffard ESA Alessandro Maltese Serco Henri Laur ESA Philippe Goryl ESA Michael Pezzopane INGV Alessio Pignalberi Università di Bologna

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Angelique Garcia National Geospatial Agency (NGA) Andreas Pollinger University of Graz Roberta Sparvoli University of Rome Tor Vergata Cristian De Santis University of Rome Tor Vergata Alessandro Sotgiu University of Rome Tor Vergata Livio Conti UNINETTUNO University Mirko Piersanti University of Rome Tor Vergata Piero Diego INAF - IAPS Igor Bertello INAF - IAPS Giuseppe Consolini INAF - IAPS Simona Zoffoli ASI - Agenzia Spaziale Italiana Piergiorgio Picozza University of Rome Tor Vergata Heilig Balázs Mining and Geological Survey of Hungary Pedro Resendiz University Of Alberta Ask Neve Gamby DTU - Space

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APPENDIX 2 - SWARM DQW#8 AGENDA

Day 1 Monday 08/10/2018

Location: Room Magellan (ESA-ESRIN, Building

2) 12:00 14:00 Registration Co-chairs: Rune Session 1: Mission overview Floberghagen Jerome Bouffard 14:00 14:10 Welcome by ESA Maurice Bourgeaud

14:10 14:20 Workshop introduction and logistics Jerome Bouffard Swarm - status overview and plans for the extended 14:20 14:35 Rune Floberghagen mission Status of present and perspectives for future Swarm 14:35 14:50 Nils Olsen DISC activities Enkelejda Qamili / Pierre 14:50 15:05 Magnetic package instruments and processors Vogel Lorenzo Trenchi / Pierre 15:05 15:20 Electric field instruments and processors Vogel 15:20 15:35 GPS and Accelerometer instruments and processors Christian Siemes

15:35 16:00 Coffee break

16:00 16:15 Status of Flight Operations Segment Ignacio Clerigo

16:15 16:30 VirES for Swarm - Visualization platform status Martin Paces

16:30 16:45 Swarm PDGS Status & Outlook Antonio de la Fuente

16:45 17:00 Constellation status of the Swarm mission Detlef Sieg

17:00 17:15 Swarm Echo - A Multi-mission Mission Greg Enno

17:15 17:30 CSES mission and the preliminary results Xuhui Shen

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Day 2 Tuesday 09/10/2018

Location: Room Magellan A (ESA-ESRIN, Building 2 )

Chair: (splinter Session 2: Magnetic field measurements Enkelejda session) Qamili The status of the high performance VFM and its operations on the Jose M. G. 08:30 08:45 three Swarm satellites Merayo Recent developments in the calibration and disturbance corrections Lars Toffner 08:45 09:00 of the Swarm magnetic measurements Clausen Peter 09:00 09:15 Modelling the magnetic perturbation from the thermal blankets Brauer Towards correcting ASM data for the Sun-related thermoelectric Pierre 09:15 09:30 effect Vigneron About the baseline `0505' `MAG-LR L1b' provisorial magnetic field Martin 09:30 09:45 data set evaluated by GFZ `Mag.num' modelling (TBC) Rother Gauthier 09:45 10:00 New ASM 250 Hz burst mode science data Hulot

10:00 10:30 Discussion

10:30 11:00 Coffee break

Pierre 11:00 11:15 Geomagnetic field modeling based on ASMV experimental data. Vigneron Kim 11:15 11:30 Pc1 wave studies using Swarm Hyanpyo Detection and characteristics of RFI signal in the frequency range up Ewa 11:30 11:45 to 10Hz Slominska High frequency content in 50Hz magnetic data / 1Hz spike in the 11:30 12:00 Jan Miedzik 50Hz magnetic data Matija 12:00 12:15 Thermal instability of the STR mounting and correction model (TBC) Herceg Swarm Optical Bench ground tests on thermo-elastic stability - root Hauke 12:15 12:30 cause analysis on star tracker IBA anomaly Thamm

12:30 13:00 Discussion

13:00 14:00 Lunch

Chair: (splinter Session 3: Electric field measurements Lorenzo session) Trenchi

Location: Room Magellan A (ESA-ESRIN, Building 2 )

Serenella Di 14:00 14:15 One Year of EFI Operations Betta Johnathan 14:15 14:25 Swarm EFI TII calibration and datasets Burchill Johnathan 14:25 14:35 Report on using the Swarm LPs to derive ion drift and mass Burchill Johnathan 14:35 14:45 One year of EFI-TII operations: TII image improvement Burchill Applicability of DMSP Driftmeter Data for the Swarm EFI TII Ion Alexei 14:45 15:00 Cross-Track Flow Data Calibration Kouznetsov

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Levan 15:00 15:15 Validation of Swarm EFI ion drift velocities Lomidze Octav 15:15 15:30 Progress report on the validation / optimization of electric field data Marghitu

15:30 16:00 Discussion

16:00 16:30 Coffee break

Stephan 16:30 16:45 Langmuir Probe data and data products Buchert Characterisation of ionospheric electron density and temperature 16:45 17:00 Igino Coco from different datasets and in different geomagnetic conditions. Analysis of the electron temperature from the LP sweep mode and Vladimir 17:00 17:15 comparison with other modes and IRI Truhlik Juan Assessment of electron temperature across equatorial plasma 17:15 17:30 Rodriguez- depletions Zuluaga Matthias 17:30 17:45 Estimation of the reduced ion mass m(eff) from Langmuir probe data Foerster Richard 17:45 18:00 Regression approach to Langmuir probe measurement interpretation Marchand Simulation-based interpretation of front plate and Langmuir probe Richard 18:00 18:15 measurements. Marchand

18:15 18:45 Discussion

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Day 2 Tuesday 09/10/2018

Location: Room Magellan B (ESA-ESRIN, Building 2 ) Chair: (splinter Session 4b: GPSR and accelerometer Christian session) Siemes 08:30 09:00 Swarm accelerometer data calibration and processing Sergiy Svitlov

Impact of gas-surface interactions modelling on acceleration-derived Günther 09:00 09:15 thermosphere data March Jose van den 09:15 09:30 (Title not yet provided) IJssel Reduced-dynamic and kinematic SWARM orbit determination using Oliver 09:30 09:45 ambiguity fixing Montenbruck

09:45 10:30 Discussion

10:30 11:00 Coffee break Eelco 11:00 11:15 Status of L2 thermosphere density products Doornbos Sean 11:15 11:30 Swarm density assimilation in DTM Bruinsma Jaeheung 11:30 11:45 Small-scale wave signatures in the L2 DNSCWND data Park The GPS Attitude, Positioning, and Profiling receivers (GAP) of Christopher 11:45 12:00 Swarm-E: Status of data reduction and availability Watson Oliver 12:00 12:15 CASSIOPE/ePOP precise orbit determination - First results Montenbruck 12:15 13:00 Discussion

13:00 14:00 Lunch Chair: (splinter Session 4a: GPSR and accelerometer Christian session) Siemes Location: Room Magellan B (ESA-ESRIN, Building 2 )

Monthly gravity fields from Swarm GPS orbits by decorrelated Ales 14:00 14:15 acceleration approach Bezdek Mitigation of ionospheric signatures in Swarm GPS gravity filed Lucas 14:15 14:30 estimation using weighting strategies Schreiter Daniel 14:30 14:45 Combination of Swarm gravity fields on normal equation level Arnold Pieter 14:45 15:00 Multi-approach gravity field models from Swarm GPS data Visser Mitigation of ionospheric effects on Swarm GPS observations and 15:00 15:15 Le Ren kinematic orbits Influence of orbit filtering strategies on Swarm time-variable gravity Christina 15:15 15:30 fields Luck 15:30 16:00 Discussion

16:00 16:30 Coffee break

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Day 3 Wednesday 10/10/2018

Location: Room Magellan (ESA-ESRIN, Building 2 )

Chair: Kathy

Session 5: Higher level products (Internal) Whaler Precise model of the core magnetic field over the satellite 08:30 08:45 Vincent Lesur area

08:45 09:00 The origin of core field secular acceleration pulses Chris Finlay

Utility of Virtual Observatory secular variation estimates for 09:00 09:15 Kathy Whaler core flow modelling Mantle conductivity time-domain chain: Recent results and 09:15 09:30 Jakub Velímský future plans

09:30 09:45 Title not yet provided Alexander Grayver

09:45 10:00 LCS-1 update Erwan Thebault

10:00 10:15 Swarm for Solid Earth modelling Jörg Ebbing

10:15 10:35 Discussion

10:35 11:00 Coffee break Co-Chairs: Claudia Session 6: Higher level products (External) Stolle & Kirsti Kaurustie The average magnetic field and polar current system 11:00 11:15 Karl Laundal (AMPS) model An empirical climatological model of the occurrence of F 11:15 11:30 Claudia Stolle region equatorial plasma irregularities DIFI-4 and beyond: modeling the ionospheric magnetic field 11:30 11:45 Arnaud Chulliat from an optimal Swarm constellation

11:45 12:00 Evaluation and analysis of FACs Malcolm Dunlop

ROT and ROTI derived from the Swarm Level 2 TEC 12:00 12:15 Guram Kervalishvili product. Specification of large-scale ionospheric irregularities by 12:15 12:30 Irina Zakharenkova Swarm GPS observations Field-aligned current density estimation with Swarm: results 12:30 12:45 Adrian Blagau obtained under ESA-SIFACIT project

12:45 13:05 Discussion

13:05 14:00 Lunch

The relationship between in situ plasma density 14:00 14:15 Lasse Clausen measurements and TEC IPIR: Ionospheric Plasma IRregularities characterised by 14:15 14:30 Wojciech Miloch Swarm First conductance estimates based on combined Swarm E 14:30 14:45 and B field measurements & Auroral Electrojet boundary Kirsti Kauristie and peak intensity products by the SWARM-AEBS project Swarm ASM burst mode to sound the ionosphere below the 14:45 15:00 Pierdavid Coisson satellites Performance, data format and results from the SWARM high John Leif 15:00 15:15 energy particle detection experiment Joergensen Possible use of Swarm magnetic field data for the 15:15 15:30 Yosuke Yamazaki specification of Sq currents and thermospheric winds Investigating Swarm data products for 4D ionosphere 15:30 15:45 Susan Skone characterization

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15:45 16:05 Discussion

16:05 16:30 Coffee break

The auroral oval boundaries derived from the Swarm 16:30 16:45 Chao Xiong magnetic measurements Natural Orthogonal Composition analysis of Swarm electron 16:45 17:00 Igino Coco density and temperature in the equatorial region New ULF & ELF wave indices derived from Swarm 17:00 17:15 observations to investigate magnetosphere-ionosphere George Balasis coupling' BGS enhancement of fast-track magnetosphere and 17:15 17:30 William Brown observatory data products. Linear vs. nonlinear methods for detecting magnetospheric 17:30 17:45 Tommaso Alberti and ionospheric current systems patterns

17:45 18:20 Discussion

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Day 4 Thursday 11/10/2018

Room Magellan (ESA-ESRIN, Building 2 )

Chair: Session 7: Swarm - CSES Synergies Gauthier Hulot The Data Quality Evaluation System for China Seismo- 08:30 08:45 Jing Zhang Electromagnetic Satellite Werner 08:45 09:00 Status of the scalar magnetometer aboard CSES Magnes The in-orbit performance assessment methods for high precision 09:00 09:15 Bin Zhou magnetometer onboard of China Seismo-Electromagnetic Satellite

09:15 09:30 Some Initial Results from CSES High Precision Magnetometer Yanyan Yang

Magnetic interference analysis in high precision magnetometer Bingjun 09:30 09:45 data onboard of CSES Cheng Electron density data obtained by LAP and GRO onboard CSES 09:45 10:00 Xiuying Wang Satellite A Cross-Validation Method for Electromagnetic Sensors on the 10:00 10:15 Ziyang Li Same Platform

10:15 10:35 Discussion

10:35 11:00 Coffee break

Chair: Session 8: Swarm - Echo Guram Kervalishvili 11:00 11:15 Accessing e-POP Data Andrew White

11:15 11:30 Updates to the Swarm Echo magnetic field data products David Miles

11:30 11:45 On the status of the Radio Receiver Instrument on Swarm Echo Gareth Perry Overview of e-POP radio science research with the Radio Receiver Gordon 11:45 12:00 Instrument RRI to date. James Possible investigations with RRI in the future. 12:00 12:15 Swarm Echo ion composition new data product Andrew Yau

Andrew 12:15 12:30 Swarm Echo: Fast Auroral Imager Data Howarth

12:15 12:45 e-POP SEI electron data calibration and new scientific results Yanyan Shen

12:45 13:05 Discussion

13:05 14:00 Lunch

Chair: Roger

Session 9: Multi-mission Synergies Haagmans Core field modeling with a combined dataset from CHAMP, DMSP 14:00 14:15 Partick Alken and Swarm

14:15 14:30 Cryosat magnetometer data calibration Nils Olsen

Platform-magnetometer calibrations: recent efforts on GOCE and 14:30 14:45 Cryosat - and the ePOP magnetometer data set on its way Martin Rother towards a Swarm-E `L1b' product. Observation capabilities of GOCE and GRACE related to the Swarm Eelco 14:45 15:00 mission objectives Doornbos

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Application of the multi-satellites observations for ionospheric 15:00 15:15 Yurii Cherniak climatology and space weather research Comparison of TEC specifications obtained from a data Ludger 15:15 15:30 assimilation model with Swarm observations Scherliess Similarities and differences between SWARM and SNIPE 15:30 15:45 constellation (Small scale magNetospheric and Ionospheric Plasma Junga Hwang Experiments)

15:45 16:05 Discussion

16:05 16:25 Coffee break

Chair: Eelco

Session 10: Swarm & SPACE 4.0I Doornbos

16:25 16:40 NanoMagSat/Swarm Delta nanosatellite project Gauther Hulot

Orbital observation data Predicting model with deep learning 16:40 16:55 Xiuying Wang method Anomaly Detection of Swarm-related Data Using Machine 16:55 17:10 Yaxin Bi Learning-based Data Analytics Constantinos 17:10 17:25 A machine learning approach for automated ULF wave recognition Papadimitriou Guram Kervalishvili & 17:25 17:45 Future Earth Observation Swarm Mission Website the ESA web team 17:45 18:10 viresclient: A new Python package for interacting with VirES Ashley Smith

18:10 18:30 Discussion

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Day 5 Friday 12/10/2018

Room Magellan (ESA-ESRIN, Building 2 )

Session 4: Summaries , Recommendations & Future Chair: Jerome Bouffard

09:00 09:15 Summary & Recommendations on MAG Splinter session 2 Enkelejda Qamili

09:15 09:30 Summary & Recommendations on EFI Splinter session 3 Lorenzo Trenchi

Summary & Recommendations on ACC GPSR Splinter 09:30 09:45 Christian Siemes session 4 Summary & Recommendations on Higher Level Product 09:45 10:00 Kathy Whaler (internal) session 5 Summary & Recommendations on Higher Level Product Claudia Stolle & Kirsti 10:00 10:15 (external) session 6 Kaurustie Summary & Recommendations on Swarm - CSES 10:15 10:30 Gauthier Hulot Synergie session 7

10:30 11:00 Coffee break

Summary & Recommendations on Multi-mission 11:00 11:15 Guram Kervalishvili Synergies session 8 Summary & Recommendations on Swarm - Echo session 11:15 11:30 Roger Hagmans 9 Summary & Recommendations on Swarm & SPACE 4.0I 11:30 11:45 Eelco Doornbos session 10

11:45 12:00 Discussion on Swarm constellation evolution Detlef Sieg

12:00 12:20 Mission outlook Rune Floberghagen

12:20 12:40 Swarm DQW#9 Conclusions Jérôme Bouffard

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