Session G4.2

G4.2 | Modern Concepts for Ground and Space Observations of the Earth Gravity Field

Modern Concepts for Ground and Space Observations of the Earth Gravity Field

Convener: Marvin ReichECSECS | Co-conveners: Jürgen Müller, Daniele Carbone, Elske de Zeeuw - van Dalfsen, Sébastien MerletECSECS

Orals

| Thu, 18 Apr, 14:00–15:45 (CEST)

Room D1

Posters on site

| Attendance Fri, 19 Apr, 10:45–12:30 (CEST) | Display Fri, 19 Apr, 08:30–12:30

Hall X2

Recent developments in different fields have enabled new applications and concepts in the space- and ground-based observation of the Earth’s gravity field. In this session, we discuss the benefit of new sensors and techniques and their ability to provide precise and accurate measurements of Earth’s gravity.
We encourage the dissemination of results from geoscience applications of absolute quantum gravimeters, which are gradually replacing devices based on the free-fall of corner cubes, since they allow nearly continuous absolute gravity measurements and offer the possibility to measure the gravity gradient. Quantum sensors are also increasingly considered for future gravity space missions. In addition, we welcome results from gravimeters based on other technologies (e.g., MEMS or superconducting gravimeters) that have been used to study the redistributions of subsurface fluid masses (water, magma, hydrocarbons, etc.) in permanent deployment or field surveys.
Besides gravimeters, other concepts can provide unique information on the Earth’s gravity field. According to Einstein’s theory of general relativity, frequency comparisons of highly precise optical clocks connected by optical links give direct access to differences of the gravity potential (relativistic geodesy) over long baselines. In future, precise optical clock networks can be applied for defining and realizing a new international height system or to monitor mass variations.
Laser interferometry between test masses in space with nanometer accuracy – successfully demonstrated through the GRACE-FO mission – also belongs to these novel concepts, and even more refined concepts (tracking swarms of satellites, space gradiometry) will be realized in the near future.
We invite presentations illustrating the state of the art of those novel techniques, that will open the door to a vast bundle of applications, including the gravimetric observation of the Earth-Moon system with high spatial-temporal resolution as well as the assessment of terrestrial mass redistributions, occurring at different space and time scales and providing unique information on the processes behind, e.g., climate change and volcanic activity.
This session is organized jointly with the IAG (International Association of Geodesy) project "Novel Sensors and Quantum Technology for Geodesy (QuGe)" and DFG Collaborative Research Centre “Relativistic and quantum-based geodesy (TerraQ)”.

Orals: Thu, 18 Apr | Room D1

Chairpersons: Marvin Reich, Jürgen Müller

14:00–14:05

5-minute convener introduction

14:05–14:25

EGU24-19937

solicited

Highlight

On-site presentation

CARIOQA-PMP: developing quantum sensors for earth observation

Christian Schubert

For the CARIOQA-PMP Consortium

Due to their performance especially at low frequencies, quantum sensors based on atom interferometry are expected to enhance the capabilities of future missions for earth observation. Atom interferometers, e.g. in a configuration as an accelerometer / gravimeter are routinely operated in laboratories and commercial versions exist. Additionally, payloads with demonstration experiments on cold atoms and atom interferometry were implemented on microgravity platforms including parabola flights, a drop tower, and sounding rockets, significant steps towards a future deployment on a satellite, but each limited in microgravity time.

Both the specific environment of a satellite and the desired performance of a future, space-borne quantum accelerometer imply strict requirements and consequently the need for further technology developments in comparison to the current state of the art. This context sets the scope for the project CARIOQA-PMP (Cold Atom Rubidium Interferometer in Orbit for Quantum Accelerometry – Pathfinder Mission Preparation). Supported by scientists, the main task is the development of an engineering model of a quantum accelerometer for a dedicated pathfinder mission in space. Additionally, the project considers the scientific background, especially in the context of a possible future space mission.

This contribution will present the motivation and the approach of CARIOQA-PMP for enabling future quantum-sensor-enhanced missions for earth observation.

CARIOQA-PMP is a joint European project, including experts in satellite instrument development (Airbus, Exail SAS, TELETEL, LEONARDO), quantum sensing (LUH, SYRTE, LP2N, LCAR, ONERA, FORTH), space geodesy, Earth sciences and users of gravity field data (LUH, TUM, POLIMI, DTU), as well as in impact maximisation and assessment (PRAXI Network/FORTH, G.A.C. Group), coordinated by the French and German space agencies CNES and DLR under CNES lead. Funded by the European Union.

How to cite: Schubert, C.: CARIOQA-PMP: developing quantum sensors for earth observation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19937, https://doi.org/10.5194/egusphere-egu24-19937, 2024.

14:25–14:35

EGU24-11177

ECS

On-site presentation

Assessment of a quantum gravity mission by the space-wise approach in the framework of the QSG4EMT project

Lorenzo Rossi, Mirko Reguzzoni, Öykü Koç, and Federica Migliaccio

Quantum technology is becoming more and more popular in science and applications. For some years now the possibility of equipping a future satellite mission with quantum instrumentation has been investigated to improve the current knowledge of the Earth’s gravity field. In this framework the QSG4EMT project, which is funded by ESA, aims at investigating different mission principles (low-low satellite-to-satellite tracking with one or more pairs, gradiometry, etc.) especially with the aim of retrieving the time variations of the gravity field. One of the processing strategies that are used for this assessment is the so-called space-wise approach, which is mainly based on a least-squares collocation scheme passing through the estimation of gridded values to adapt the noise filtering level to the local characteristics of the static and time-variable gravity field. This approach is naturally used for local/regional solutions, but it can be also applied for global modelling by patching overlapped regional solutions all over the world and then performing a spherical harmonic analysis. In this work, the space-wise approach is used to assess the performances of different mission scenarios of future missions having on board purely quantum or quantum-electrostatic hybrid accelerometers. The focus is both on the estimation of the total water storage and on the comparison of the information retrieved from global and local solutions.

How to cite: Rossi, L., Reguzzoni, M., Koç, Ö., and Migliaccio, F.: Assessment of a quantum gravity mission by the space-wise approach in the framework of the QSG4EMT project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11177, https://doi.org/10.5194/egusphere-egu24-11177, 2024.

14:35–14:45

EGU24-17378

ECS

On-site presentation

Gravitational field recovery via inter-satellite redshift measurements

Jan Patrick Hackstein, Dennis Philipp, and Eva Hackmann

Satellite gravimetry is a common tool to monitor global changes in the Earth system, generally utilising accelerometers aboard satellites to measure acting forces along the orbits. In contrast, high-precision atomic clocks are used in first experiments in terrestrial gravimetry to measure physical heights. In relativistic gravity, a comparison of two clocks is sensitive to their relative positions and velocity, making clocks ideal tools to investigate Earth’s gravity field. However, one important obstacle for Earth-satellite chronometry is the low measurement accuracy of satellite velocities, which enter into the redshift via the Doppler effect.
We present an alternative approach based on the framework of general relativity without velocity measurements from ground stations, instead measuring redshift between satellite pairs equipped with clocks via laser ranging. This method promises higher accuracy for gravity field recovery by improving control of the Doppler effect. We investigate this problem in analytically given spacetimes as well as in the general first post-Newtonian approximation of Earth’s gravity field, and discuss the prospects for gravity field recovery.

How to cite: Hackstein, J. P., Philipp, D., and Hackmann, E.: Gravitational field recovery via inter-satellite redshift measurements, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17378, https://doi.org/10.5194/egusphere-egu24-17378, 2024.

14:45–14:55

EGU24-9463

ECS

On-site presentation

Quantum-based Accelerometers for Satellite Gravimetry Missions

Nina Fletling, Annike Knabe, Jürgen Müller, Matthias Weigelt, and Manuel Schilling

Accelerometers are an essential component of satellite gravimetry missions, as the non-gravitational forces acting on the satellites must be known in order to determine the Earth's gravity field. However, the accelerometers currently in use are one of the limiting factors regarding the accuracy of the determined gravity field, which opens up room for improvement. Among other techniques, quantum-based accelerometers are promising candidates to be applied in the future.

In order to achieve the required technology readiness level for operation in space, a pathfinder mission is planned to demonstrate the technology. This mission is being prepared in the framework of the Cold Atom Rubidium Interferometer in Orbit for Quantum Accelerometer - Pathfinder Mission Preparation (CARIOQA-PMP) project funded by the European Union. In addition to designing the pathfinder mission and instrument to achieve a specific performance, simulations are carried out based on the expectable performance not only for the pathfinder mission but also beyond on the utilisation of quantum-based accelerometers in future satellite gravimetry missions. This includes a broad study on different mission types, such as a single satellite with high-low satellite-to-satellite tracking, as foreseen in the pathfinder mission, or a satellite constellation with GRACE-FO-like conditions utilising low-low satellite-to-satellite tracking. Here, closed-loop simulations are used to investigate under which conditions the determined gravity field solution benefits from a quantum-based accelerometer compared to a classical electrostatic one and which challenges still need to be addressed in order to improve resolution and accuracy.

How to cite: Fletling, N., Knabe, A., Müller, J., Weigelt, M., and Schilling, M.: Quantum-based Accelerometers for Satellite Gravimetry Missions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9463, https://doi.org/10.5194/egusphere-egu24-9463, 2024.

14:55–15:05

EGU24-3560

On-site presentation

Absolute Quantum Gravimeter for Field Applications

Jérémie Richard, Laura Antoni-Micollier, Pierre Vermeulen, Maxime Arnal, Romain Gautier, Camille Janvier, Vincent Ménoret, Cédric Majek, Bruno Desruelle, and Peter Rosenbusch

Absolute gravity measurements at the level of 1 µGal using cold atom quantum technology have been demonstrated in the laboratory in 1992 and have ever since received an increasing interest from the geophysics community [1]. In 2015, Exail launched on the marketplace the Absolute Quantum Gravimeter (AQG) [2]. Cutting-edge technology developments brought the necessary easy-of-use, autonomy, and robustness for field deployment. More than 15 units have since been produced for various geophysical applications, including hydrology and volcanology.

Designed for field applications with autonomous or remote-controlled operation, the AQG does not require heavy vibration isolation equipment thanks to an integrated real time vibration compensation module which hybridizes the quantum measurement with a built-in classical accelerometer. As a result, all units reproducibly achieve a resolution of 10^-9 g after < 2 hours of measurement at our inner-city factory site or after < 40 minutes at a quiet site, as we will demonstrate in this talk [2,4]. Moreover, we will present recent progress on the AQG including a gravity measurement campaign that has been on-going for 3 years now near the summit of Mt Etna [3,4]. Finally, we will detail our study of systematic effects affecting the instrument, whose evaluation is required to build a rigorous accuracy (or trueness) budget.

[1] M. Kasevich, S. Chu. Measurement of the gravitational acceleration of an atom with a light-pulse atom interferometer. Applied Physics B, 1992, vol. 54, p. 321-332.
[2] V. Ménoret et al, Gravity measurements below 10^-9 g with a transportable absolute quantum gravimeter. Scientific Reports, 2018, 8, pp.12300.
[3] L. Antoni-Micollier et al Detecting volcano-related underground mass changes with a quantum gravimeter. Geophysical Research Letters, vol. 49, issue 13, e2022GL097814 (2022).
[4] L. Antoni-Micollier et al, Absolute quantum gravimeters and gradiometers for field measurements. IEEE Instrumentation & Measurement Magazine (submitted).

How to cite: Richard, J., Antoni-Micollier, L., Vermeulen, P., Arnal, M., Gautier, R., Janvier, C., Ménoret, V., Majek, C., Desruelle, B., and Rosenbusch, P.: Absolute Quantum Gravimeter for Field Applications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3560, https://doi.org/10.5194/egusphere-egu24-3560, 2024.

15:05–15:15

EGU24-20659

On-site presentation

Absolute Quantum Gravimeter as a promising field sensor for volcano monitoring

Michel Diament, Guillaume Lion, Gwendoline Pajot-Métivier, Sébastien Merlet, and Sébastien Déroussi

Soufrière, an active volcano in Guadeloupe (French West Indies) monitored by the Volcanological and Seismological Observatory of Guadeloupe (OVSG), requires a comprehensive understanding of mass transfers, including water movements. To address this, a gravity repetition network was established in the 1980s following the volcano's last major eruption in 1976. In 2011, initial absolute measurements were conducted using a Micro-g Lacoste portable absolute gravity meter A10 #14.

As part of the EQUIPEX RESIF program, aimed at meeting the scientific community's seismic and gravimetric instrument needs in France, the first absolute quantum field gravimeter (AQG-B01) was acquired. This advanced instrument, designed for diverse applications, including volcano gravity monitoring, utilizes atom interferometry with lasers to measure gravity by manipulating 'atomic waves' with a cloud of free-falling cold atoms at a cycling rate of 2 Hz.

In March 2023, a fieldwork was undertaken with the AQG-B01 as an initial step toward modern gravity monitoring of Soufrière. The specific goals included reoccupying stations within the microgravity network and identifying new sites for expanding the network, selecting an appropriate location for a permanent station near the summit based on a Lacoste&Romberg D meter, testing the AQG-B01 under challenging tropical conditions (humidity up to 85%, mean temperature of 24°C), assessing the use of an external power supply for the AQG, and evaluating the ease of installation and accuracy of measurements with the AQG, as specified by the manufacturer.

This work primarily focuses on the latter three objectives.

How to cite: Diament, M., Lion, G., Pajot-Métivier, G., Merlet, S., and Déroussi, S.: Absolute Quantum Gravimeter as a promising field sensor for volcano monitoring, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20659, https://doi.org/10.5194/egusphere-egu24-20659, 2024.

15:15–15:25

EGU24-10880

On-site presentation

Recent improvements in gravity precision from CG-6 sensors

Ola Eiken

Gravity sensors for high-precision monitoring or mapping can be grouped into 1) Relative spring, 2) Absolute free-fall, 3) Absolute cold atom, and 4) Superconducting. While all can provide valuable data, few comparisons of performance or cost have been published. Here we report on performance of CG-6 relative gravimeters and discuss how it relates to other sensors.

The Scintrex CG-6 sensor has weight of 5.5 kg and volume of 10,8 litre, which is less than previous quartz sensors. While the manufacturer specifies 5 µGal repeatability, Francis (2021) reported better performance and improved drift, noise level, tilt susceptibility and temperature influence. Mao et al., (2022) reported uncertainty down to 0.1 µGal in the laboratory. We have analysed more than 2000 survey records from as diverse environments as the desert and the seafloor. Station repeatability is a robust measure of the precision for surveys with multiple station visits and sensors. Data redundancy allows in-situ calibration of scale factors and parameters for tilt and temperature corrections. Up to 10^oC temperature difference between night and day gave no remaining correlation between sensor temperature and gravity residuals, but some diurnal drift periodicity, and repeatabilities <1.5 µGal were achieved. For more stable external temperatures, the scatter of residuals were well below 1 µGal. Both merits are significantly better than for the older CG-5 sensors in similar survey setups.

More instruments and measurements will improve the precision – and increase the cost. Most microgravity surveys have so far been done in R&D settings, and the costs have been baked into a wider project. The relation between cost and precision can be predicted and the optimal choice of survey parameters made in an industrial setting. The absolute free-fall A-10 gravimeter had in our case inferior precision compared to CG-6 for the same acquisition effort. The benefits of absolute measurements for monitoring surveys remain to be demonstrated, and it is too early to judge the performance of cold atom gravimeter developments. Superconducting sensors give time-series of superior resolution, but their limited mobility reduces the spatial resolution – or drive the cost. They can give control points with a lower detection threshold, but arial surveys are required for fair coverage of a subsurface target.

Obtaining <1 µGal precision with relative gravimeters requires good instruments, multiple sensors/repeats, and comprehensive data processing. Recent improvements by CG-6 gravimeters increase technical and economic opportunities for providing valuable gravity monitoring data. Future sensor developments by e.g. cold atom or MEMS should be benchmarked against the CG-6, not the older and less precise CG-5 sensors.

References

Francis, O. 2021: Performance assessment of the relative gravimeter Scintrex CG-6. Journal of Geodesy 95: 116.

Mao, Q., Xu, H., Cheng ,Y., Huang, T., Huang, J. And Li, Q. [2022] Apparatuses for verifying the precision of gravimeters with lifting spherical source masses. Recv. Sci. Instrum. 93, 124503.

How to cite: Eiken, O.: Recent improvements in gravity precision from CG-6 sensors, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10880, https://doi.org/10.5194/egusphere-egu24-10880, 2024.

15:25–15:35

EGU24-19218

ECS

On-site presentation

Revisiting non-tidal atmospheric and oceanic gravity corrections for terrestrial gravimetry

Kyriakos Balidakis, Ezequiel Antokoletz, Roman Sulzbach, Henryk Dobslaw, Hartmut Wziontek, Christian Voigt, Robert Dill, and Ludger Timmen

Mass redistribution within Earth’s atmosphere and oceans affects gravity time series recorded by precise superconducting and quantum gravimeters at a multitude of temporal scales. While the largest component of the systematic disturbances is attributed to tides mainly in the oceans, the solid Earth, and to a smaller extent also the atmosphere, synoptic weather features also cause non-negligible gravity anomalies. The accurate description of these effects requires a high-resolution representation of certain components of the instantaneous Earth system state, namely the 3D atmospheric density and the ocean bottom pressure distribution. In this contribution, we calculate gravity anomalies induced by the Newtonian attraction of the mass anomalies and the loading effect they exert on Earth’s crust, employing the state-of-the-art meso-beta scale numerical weather model ERA5 reanalysis from ECMWF. We compare the ERA5-derived gravity anomalies to those provided by ATMACS, a service that features weather-driven gravity anomaly corrections for most superconducting gravimeter sites based on the operational model ICON-global, from the German Weather Service. In this work, we place our focus on non-tidal contributions only, while tidal signatures are estimated based on the gravity anomaly time series. The ocean state is based on a recent MPIOM simulations forced consistently from ERA5 which is also the basis of the latest GRACE/GRACE-FO non-tidal atmosphere-ocean dealiasing product AOD1B RL07. To assess the effectiveness of the modelling strategy as well as the quality of the mass anomaly fields, we apply the ERA5 and ATMACS-retrieved models to a few selected superconducting gravimeter time series with a focus on sites with unusual orography such as on the small island of Helgoland located in the North Sea, and assess the band-pass filtered residuals to assess the quality of the various correction models available.

How to cite: Balidakis, K., Antokoletz, E., Sulzbach, R., Dobslaw, H., Wziontek, H., Voigt, C., Dill, R., and Timmen, L.: Revisiting non-tidal atmospheric and oceanic gravity corrections for terrestrial gravimetry, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19218, https://doi.org/10.5194/egusphere-egu24-19218, 2024.

15:35–15:45

EGU24-5316

ECS

On-site presentation

Airborne Gravimetry with Quantum Technology

Tim Jensen, René Forsberg, Andreas Stokholm, Bjørnar Dale, Yannick Bidel, Nassim Zahzam, Alexandre Bresson, and Alexis Bonnin

Posters on site: Fri, 19 Apr, 10:45–12:30 | Hall X2

Display time: Fri, 19 Apr 08:30–Fri, 19 Apr 12:30

Chairpersons: Sébastien Merlet, Elske de Zeeuw - van Dalfsen, Daniele Carbone

X2.25

EGU24-3305

ENIGMA: East-Asian Network Initiative for Gravity Measurement Alliance: A Proposal and Science Cases

(withdrawn)

Edwin J. Son, Jeong Woo Kim, John J. Oh, Hwansun Kim, Cheinway Hwang, Ching-Chung Cheng, Yoshihiro Ito, Yoshiyuki Tanaka, Wenbin Shen, Wei Luan, Minzhang Hu, Ziwei Liu, Heping Sun, Xiaodong Chen, Sangwook Bae, and Heejun Yoon

X2.26

EGU24-2746

YeMiGO: Data Processing and Analysis of Underground Superconducting Gravity Data in South Korea

(withdrawn)

John J. Oh, Mohammad Javad Dehghan, Ik Woo, Hwansun Kim, Edwin J. Son, SeungMi You, and Jeong Woo Kim

X2.27

EGU24-6235

Monitoring aquifers and subsidence with the chronometric leveling

Guillaume Lion, Kristel chanard, Gwendoline Pajot, Michel Diament, and Olivier Jamet

Subsidence poses a significant global threat to the viability and economic development of approximately one-fifth of the world's population, especially in coastal or heavily urbanized regions experiencing ground settlements ranging from centimeters per month to meters per decade. This phenomenon, driven by natural or anthropogenic factors, is intricately linked to hydrology, geology, tectonics, and the geotechnical properties of underlying formations. Multiple triggers, including underground cave collapses, organic soil oxidation, natural gas and oil extraction, and aquifer consolidation, contribute to subsidence, disrupting vital water reserves crucial for societal needs. Spatial and temporal limitations of conventional techniques like gravimetry, positioning, and spatial imaging in resolving the effects of extreme weather events and resource exploitation on subsidence prompt an exploration of their complementarity and the emergence of quantum sensors—specifically, atomic clocks sensitive to gravitational potential variations.
Since 2021, the SYRTE, IPGP, IGN, and SHOM participate in the ANR ROYMAGE project (Optical Ytterbium Mobile Atomic Clock Applied to Geodetic Exploration). The project aims to develop a transportable atomic clock prototype with sufficient performance to determine altitude differences within the T-REFIMEVE fiber network, achieving a centimeter-level uncertainty in just a few hours across points separated by hundreds of kilometers for geodetic applications. As optical atomic clocks become integral to fieldwork, their sensitivity to mass anomalies and vertical displacement becomes a crucial consideration.

Within the ANR framework, we have initiated digital tool implementation to model the signal generated by remote clock comparisons, mainly gravitationally and geometrically influenced by mass and altitude variations. The challenge lies in identifying and decorrelating signal sources to reveal the studied phenomenon. Geopotential differences, a novel geodetic observable, necessitate modeling considering gravitational signatures at the Earth's surface from buried mass anomalies (e.g., aquifers), the (in)elastic medium response to pressure changes causing vertical crust displacement, and other effects like solid Earth tides, ocean tide loading, polar motion, etc. Preliminary results suggest that clock comparisons with centimeter-level uncertainties could detect variations in regional groundwater levels.

This work proposes to assess whether chronometric leveling, in France, can complement gravimetric, spatial imaging and levelling techniques to study vertical soil displacements resulting from disturbances in underground water resources due to climatic or anthropogenic origins.

The authors acknowledge the support of the French Agence Nationale de la Recherche (ANR) under reference ANR-20-CE47-0006.

How to cite: Lion, G., chanard, K., Pajot, G., Diament, M., and Jamet, O.: Monitoring aquifers and subsidence with the chronometric leveling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6235, https://doi.org/10.5194/egusphere-egu24-6235, 2024.

X2.28

EGU24-11059

ONERA accelerometers for future gravity mission

Marine Dalin, Bruno Christophe, Vincent Lebat, Damien Boulanger, Francoise Liorzou, Manuel Rodrigues, Nassim Zahzam, Yannick Bidel, and Alexandre Bresson

The 2017-2027 Decadal Survey for Earth Science and Applications from Space has identified the Targeted Mass Change Observable as one of 5 Designated Mission. In Europe, ESA has confirmed at Ministerial Counsel of November 2022 to continue the development on the Next Generation Gravity Mission with a Phase B.

These missions will continue the observation provided by GRACE and GRACE-FO. In these missions and the future concepts, the accelerometer provides either the gravity signal in a gradiometer configuration (GOCE type mission), or the non-gravitational acceleration to be suppressed to the ranging measurement between two satellites (GRACE-type mission).

ONERA has procured the accelerometer for all the previous gravity missions (GRACE, GOCE, GRACE-FO) and works to improve the scientific return of the instruments for the future missions.

In a frame of a contract with ESA, ONERA is developing its new accelerometer MicroSTAR, a high accuracy accelerometer with 3 sensitive linear acceleration measurements as well as 3 angular acceleration measurements for the attitude control or reconstruction.

In parallel, a miniaturized version of MicroSTAR with low accuracy, CubeSTAR accelerometer, is developed with internal funding. CubeSTAR is adapted for constellation or nanosat.

Another way is to improve the low-frequency noise of the accelerometer, by hybridization of electrostatic accelerometer with cold atom interferometer.

The presentation will detail these developments.

How to cite: Dalin, M., Christophe, B., Lebat, V., Boulanger, D., Liorzou, F., Rodrigues, M., Zahzam, N., Bidel, Y., and Bresson, A.: ONERA accelerometers for future gravity mission, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11059, https://doi.org/10.5194/egusphere-egu24-11059, 2024.

X2.29

EGU24-14722

Highlight

Community assessment on user requirements for future satellite gravity missions

Annette Eicker, Christina Strohmenger, Carla Braitenberg, Jürgen Kusche, Roland Pail, and Ilias Daras

Since 2002, the GRACE and GRACE-FO satellite gravity missions have been observing changes in the Earth’s gravity field. ESA and NASA are currently planning a double-pair satellite constellation MAGIC, which promises an enhanced spatial and temporal resolution compared to GRACE/-FO. After MAGIC, in the long-term post-2040-time frame, a gravity mission constellation with multiple satellite pairs equipped with novel quantum sensor instrumentation is considered as a promising candidate concept to improve the observation time series even further. It has the potential to acquire unprecedented data on key Earth processes and is expected to significantly expand the potential range of applications.

Within the ongoing ESA project “Quantum Space Gravimetry for monitoring Earth’s Mass Transport Processes” (QSG4EMT) an online questionnaire was created to assess user requirements for such a future quantum mission concept. We will present the results of this community assessment based on 135 answers from various user groups (hydrology, oceanography, glaciology, atmospheric and climate sciences, solid earth sciences, and geodesy). In addition to application-driven demands of the different disciplines regarding the required spatial and temporal resolution, accuracy, and latency, we discuss the expected added benefits of hypothetical future mission scenarios and outline possible new application fields.

How to cite: Eicker, A., Strohmenger, C., Braitenberg, C., Kusche, J., Pail, R., and Daras, I.: Community assessment on user requirements for future satellite gravity missions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14722, https://doi.org/10.5194/egusphere-egu24-14722, 2024.

Discussion Post a comment

X2.30

EGU24-14996

ECS

CARIOQA-PMP quantum accelerometer simulation

Manuel Schilling, René Forsberg, Naceur Gaaloul, Thomas Gruber, Thomas Lévèque, Federica Migliaccio, Jürgen Müller, Franck Pereira Dos Santos, and Nassim Zahzam and the CARIOQA-PMP Consortium

Satellite gravimetry missions have been providing a global measure of Earth's mass transport for more than 20 years. This provides insights into the solid Earth, cryosphere, ocean dynamics and hydrology. Planned NASA and ESA missions will continue this observation well into the 2030s. They are likely to be based on the technology currently used on the GRACE-FO mission, with some further developments, e.g. in laser ranging technology. A higher temporal and spatial resolution of these gravity field products, currently limited to a few hundred km for 1 cm equivalent water height, is required to meet future user need.

One of the limitations is related to instrumental effects, of which the accelerometer is a major aspect. Quantum-based accelerometers are a potential improvement for future missions, but the required technology readiness level (TRL) for key technologies currently precludes deployment. A European pathfinder mission is planned to increase the TRL and demonstrate the technology in space.

Under the Horizon Europe funding programme, technology development and maturation are being promoted and "the [Quantum Space Gravimetry] Pathfinder mission shall be launched within this decade, paving the way for the deployment of an EU [Quantum Space Gravimetry] mission within the next decade". Within this framework, the Cold Atom Rubidium Interferometer in Orbit for Quantum Accelerometer - Pathfinder Mission Preparation (CARIOQA-PMP) project is the first step in the design and preparation of the Pathfinder mission. It identifies user needs, prepares simulation tools and develops an engineering model of the quantum accelerometer.

This presentation will give an overview of the scientific activities within CARIOQA-PMP, including the link between hardware design and specification, as well as the planning for the Pathfinder mission and a future gravimetry mission. The focus will be on the elements and workflow of the simulation of the quantum sensor on a satellite platform, combining the efforts of the physics and geodesy partners.

How to cite: Schilling, M., Forsberg, R., Gaaloul, N., Gruber, T., Lévèque, T., Migliaccio, F., Müller, J., Pereira Dos Santos, F., and Zahzam, N. and the CARIOQA-PMP Consortium: CARIOQA-PMP quantum accelerometer simulation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14996, https://doi.org/10.5194/egusphere-egu24-14996, 2024.

X2.31

EGU24-17336

ECS

Updating the ESA Earth System Model for Future Gravity Missions Simulation Studies

Linus Shihora, Kyriakos Balidakis, Robert Dill, and Henryk Dobslaw

The ESA Earth System Model (ESA ESM) provides a synthetic data-set of the time-variable global gravity field that includes realistic mass variations in atmosphere, oceans, terrestrial water storage, continental ice-sheets, and the solid Earth on a wide set of spatial and temporal frequencies. It was widely applied as a source model in simulations of for gravity missions, but has been also applied to study novel gravity observing concepts on the ground. For that purpose, the ESM needs to include a wide range of signals even at very small spatial scales which might not yet have been reliably observed by any active mission.

In this contribution, we present first steps towards an update to the current ESA ESM. We focus in particular on an evolved oceanic component which will newly include (a) deep oceanic transport variations in the Atlantic Overturning Circulation and the associated variation in oceanic bottom pressure along the shelf slope of the Western boundary; (b) an update to the realistically perturbed de-aliasing model and (c) the inclusion of the Sea-Level Equation for spatially variable barystatic sea-level variations and global mass conservation.

How to cite: Shihora, L., Balidakis, K., Dill, R., and Dobslaw, H.: Updating the ESA Earth System Model for Future Gravity Missions Simulation Studies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17336, https://doi.org/10.5194/egusphere-egu24-17336, 2024.

X2.32

EGU24-19344

ECS

Detecting the co-seismic and post-seismic gravity signal of large thrust earthquakes with Quantum Space Gravimetry mission concepts

Alberto Pastorutti and Carla Braitenberg

Co-seismic dislocation and post-seismic relaxation are mass transport processes that can be sensed by a broad array of seismological and/or geodetic techniques. Gravity observations through time have the potential of improving the amount of available information on these processes, especially when the dislocation is a-seismic and when its surface expression occurs mostly in areas that are difficult or impossible to sense with space geodesy (such as GNSS, DInSAR), as is the case for off shore areas. New mission concepts, such as those proposed for the Mass change And Geosciences International Constellation (MAGIC), have been recently assessed as capable of providing significant enhancements in the spatial and temporal resolution of gravity field products, resulting in turn in unprecedented impact on the scientific applications, including earthquake gravimetry [1]. The evolution of sensors beyond classic electrostatic accelerometers, such as future applications of Cold Atom Interferometry (CAI) on space borne platforms, has the potential to allow further steps forward in sensing the mass transport in the Earth’s system.

In this context, we aim at assessing the impact of Quantum Space Gravimetry (QSG) to earthquake detectability, by modelling a database of synthetic earthquake gravity signal, including the effect of post-seismic viscoelastic relaxation, and setting up a strategy do assess their detectability in simulated time-varying gravity field products. We compute the gravity change in time using the QSSPSTATIC [2] code and a workflow we developed to obtain the spherical harmonics (SH) expansion of the geopotential change through time. We designed the structure of this synthetic earthquake data to be easily included as part of time-varying signals used in simulations, improving the solid-Earth component of models such as AOHIS [3]. In this contribution we present the detection threshold of different events, real earthquakes ranging from M_w 9.2 to 7.6 with an assortment of depths, locations and focal mechanisms, using an SNR assessment in the spectral domain, between the modelled signal and retrieval errors (residuals) obtained from mission simulations.

This work is supported by the ESA QSG4EMT study, a collaboration between Technical University of Munich, Politecnico di Milano, Delft University of Technology, HafenCity University Hamburg, University of Bonn and University of Trieste.

[1] Daras I., March G., Pail R., Hughes C. W., Braitenberg C., Güntner A., Eicker A., Wouters B., Heller-Kaikov B., Pivetta T., & Pastorutti, A. (2023). Mass-change And Geosciences International Constellation (MAGIC) expected impact on science and applications. Geophysical Journal International, 1288–1308. https://doi.org/10.1093/gji/ggad472

[2] Wang, R., Heimann, S., Zhang, Y., Wang, H., & Dahm, T. (2017). Complete synthetic seismograms based on a spherical self-gravitating Earth model with an atmosphere-ocean-mantle-core structure. Geophysical Journal International, 210(3), 1739–1764. https://doi.org/10.1093/gji/ggx259

[3] Dobslaw, H., Bergmann-Wolf, I., Dill, R., Forootan, E., Klemann, V., Kusche, J., & Sasgen, I. (2015). The updated ESA Earth System Model for future gravity mission simulation studies. Journal of Geodesy, 89(5), 505–513. https://doi.org/10.1007/s00190-014-0787-8

How to cite: Pastorutti, A. and Braitenberg, C.: Detecting the co-seismic and post-seismic gravity signal of large thrust earthquakes with Quantum Space Gravimetry mission concepts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19344, https://doi.org/10.5194/egusphere-egu24-19344, 2024.

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X2.33

EGU24-8931

ECS

Improvement of ONERA Electrostatically suspended torsion pendulum

Nolwenn Portier, Bruno Christophe, Marine Dalin, Vincent Lebat, Françoise Liorzou, and Manuel Rodrigues

In order to meet the objectives of the Next Generation Gravity Mission (NGGM), the French Aerospace Lab ONERA is developing a new accelerometer concept MicroSTAR with three sensitive linear and three true angular acceleration measurements (Dalin et al., session G4). This instrument benefits from previous developed accelerometers which flew in the well-known gravity space missions: CHAMP, GRACE, GOCE, GRACE-FO.

The principle of operation of these accelerometers is to maintain motionless a proof-mass with respect to the surrounding electrodes using a control loop. The applied electrostatic forces needed for this control, are proportional to the accelerations suffered by the proof-mass. The proof-mass is polarized with a very thin (few micrometer) wire in order to measure precisely its position by capacitive detection with the electrodes and to avoid charging in orbit. The stiffness and damping induced by the polarization wire impact the performance of the accelerometer at low frequencies. To quantify on-ground the performance limitation due to the wire, an electrostatically suspended torsion pendulum (PTSE) is used (Willemenot 1997, Willemenot and Touboul 2000).

The PTSE is a six-axes servo-controlled accelerometer, optimized for the measurement of angular accelerations about the vertical axis. The torque noise spectral density is 1.3 10^-14 Nm/√Hz around 0.05 Hz with a 1/√f increase at lower frequency, corresponding to 10^-8 rad/s²/√Hz , and 2 10^-10 ms^-2/√Hz with a lever arm of 2cm. For instance, regarding a gold wire of 7.5µm diameter and 1.7cm length, we use it to measure theoretical stiffness of 2.5 10^-5 N/m i.e. a torsion of 10^-8 Nm/rad. In our presentation, this instrument will be described before sharing ideas for its improvement.

Willemenot, P. Touboul; Electrostatically suspended torsion pendulum. Rev Sci Instrum 1 January 2000a; 71 (1): 310–314. https://doi.org/10.1063/1.1150198

Willemenot, P. Touboul; On-ground investigation of space accelerometers noise with an electrostatic torsion pendulum. Rev Sci Instrum 1 January 2000b ; 71 (1): 302–309. https://doi.org/10.1063/1.1150197

Willemenot, Pendule de torsion à suspension électrostatique, très hautes résolutions des accéléromètres spatiaux pour la physique fondamentale. Ph.D. thesis, Université Paris 11, France, 1997

How to cite: Portier, N., Christophe, B., Dalin, M., Lebat, V., Liorzou, F., and Rodrigues, M.: Improvement of ONERA Electrostatically suspended torsion pendulum, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8931, https://doi.org/10.5194/egusphere-egu24-8931, 2024.

X2.34

EGU24-8912

Laser Ranging Interferometry for the next gravity missions

Vitali Müller, Pallavi Bekal, Malte Misfeldt, Laura Müller, Reshma Sudha, Martin Weberpals, Kolja Nicklaus, Kai Voss, and Gerhard Heinzel

X2.35

EGU24-10007

ECS

General Relativistic Chronometry from Ground and in Space

Dennis Philipp, Eva Hackmann, Jan Hackstein, and Claus Laemmerzahl

Geodesy's primary objective lies in the determination of Earth's gravity field through ground and space-based measurements. General relativity and, thus, relativistic geodesy, introduce a novel perspective, leveraging high-precision clock comparisons to potentially unveil a new tool for globally determining Earth's gravito-electric potential based on the gravitational redshift.

In the pursuit of clock-based gravimetry, which involves chronometry in stationary spacetimes, precise expressions for the relativistic redshift and timing among observers in different configurations are presented. These observers, equipped with standard clocks, move on arbitrary worldlines. The analysis reveals how redshift measurements, employing clocks on the ground and/or in space, can be harnessed to deduce the (mass) multipole moments of the underlying spacetime geometry. Importantly, our findings align with the Newtonian potential determination via conventional methods such as the energy approach.

The framework of chronometric geodesy is introduced and demonstrated across various exact vacuum spacetimes for clarity. The study extends to gravity degrees of freedom, encompassing gravito-magnetic contributions, with investigations into potential experiments for their determination. Looking ahead, upcoming gravity field recovery missions might incorporate clock comparisons as an additional resource for advanced data fusion.

How to cite: Philipp, D., Hackmann, E., Hackstein, J., and Laemmerzahl, C.: General Relativistic Chronometry from Ground and in Space, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10007, https://doi.org/10.5194/egusphere-egu24-10007, 2024.

X2.36

EGU24-15065

Assessment of different temporal clock-network solution strategies

(withdrawn)

Miltiadis Chatzinikos and Pacôme Delva

X2.37

EGU24-14607

The Study of Quantum Phenomena with the Cold Atom Lab in Microgravity

Jason Williams, Kamal Oudrhiri, David Aveline, Sofia Botsi, Ethan Elliott, James Kellogg, James Kohel, Norman Lay, Matteo Sbroscia, Christian Schneider, and Robert Thompson

The Cold Atom Lab (CAL) launched to the International Space Station (ISS) in May 2018 and has been entirely remotely operated from NASA's Jet Propulsion Laboratory since then as the world's first multi-user facility for studying ultra-cold atoms in space. CAL uses lasers and magnetic traps to cool atoms down to less than a degree above absolute zero. When clouds of atoms reach these ultracold temperatures, they form a fifth state of matter called a Bose-Einstein Condensate (BEC). Distinct from gasses, liquids, solids, and plasmas, a BEC makes the quantum properties of atoms macroscopic, so scientists can more easily observe and interact with them in the essentially limitless free-fall of ISS. An on-orbit upgrade to CAL in 2021 enabled the study of atom interferometry (AI) in space, which uses the interference of atomic matter waves as exquisitely precise sensors for fundamental forces, including gravity, accelerations, and rotations. Relevant to Earth and planetary sciences, these quantum sensors are expected to serve as precision gravity sensors for geodesy, seismology, and subsurface mapping in the near future. We will discuss our efforts to provide pioneering, microgravity-enabled quantum gas research capabilities with CAL, to demonstrate AI for the first time in Earth's orbit, to realize simultaneous, dual-species atom interferometry in space, and to mature this technology for future mission opportunities.

How to cite: Williams, J., Oudrhiri, K., Aveline, D., Botsi, S., Elliott, E., Kellogg, J., Kohel, J., Lay, N., Sbroscia, M., Schneider, C., and Thompson, R.: The Study of Quantum Phenomena with the Cold Atom Lab in Microgravity , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14607, https://doi.org/10.5194/egusphere-egu24-14607, 2024.

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X2.38

EGU24-7350

ECS

Cold Atom Interferometry Accelerometers for Future Satellite Gravity Missions

Annike Knabe, Manuel Schilling, Mohsen Romeshkani, Alireza HosseiniArani, Nina Fletling, Alexey Kupriyanov, Jürgen Müller, Quentin Beaufils, and Franck Pereira dos Santos

Satellite gravity missions are a powerful tool to measure the global Earth’s gravity field and consequently provide important information for geosciences. However, improvements in spatial and temporal resolution are required for many applications. Simulation studies are performed to quantify the influence of improved sensors, orbit parameters and measurement concepts on the recovered gravity field solution. The investigations focus primarily on accelerometers by evaluating the concept of Cold Atom Interferometry (CAI) accelerometers and their combination with electrostatic accelerometers for future satellite gravity missions.

The CAI noise behavior is mainly estimated based on the quantum projection noise, but also challenges due to the longer duration of the measurement cycle are investigated. The results of the low-low Satellite-to-Satellite Tracking (ll-SST) closed-loop simulations indicate, on the one hand, benefits from the addition of CAI and reveal, on the other hand, the dominance of background modeling errors. Furthermore, the combination of ll-SST and cross-track gradiometry is studied. In order to significantly benefit from an additional cross-track gradiometer, it has to achieve a low noise level of 1 mE and the angular velocity measurements have to ensure high accuracies.

We acknowledge the support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project-ID 434617780 – SFB 1464 and under Germany’s Excellence Strategy – EXC-2123 Quantum-Frontiers – 390837967, the support by Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) for the project Q-BAGS and the European Union for the project CARIOQA-PMP (Project-ID 101081775).

How to cite: Knabe, A., Schilling, M., Romeshkani, M., HosseiniArani, A., Fletling, N., Kupriyanov, A., Müller, J., Beaufils, Q., and Pereira dos Santos, F.: Cold Atom Interferometry Accelerometers for Future Satellite Gravity Missions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7350, https://doi.org/10.5194/egusphere-egu24-7350, 2024.

X2.39

EGU24-16325

Towards a realistic modelling of gravimetric errors in future missions equipped with quantum sensors

Joao de Teixeira da Encarnacao, Christian Siemes, Ilias Daras, Aaron Strangfeld, Philipp Zingerle, and Roland Pail

Cold Atom Interferometry (CAI) stands poised as a groundbreaking technique in satellite gravimetry, offering unparalleled precision and unbiased measurements. Despite the numerous studies on CAI's conceptual measurement techniques, attitude reconstruction accuracy poses a critical challenge. This submission seeks to bridge this gap by conducting an analysis of state-of-the-art attitude sensors and their suitability for upcoming quantum low-low satellite-to-satellite and gravity gradiometry missions utilizing CAI instruments.

Acknowledging the immense promise of Cold Atom Interferometry, we emphasise the need to put this conceptual potential in the context of the accuracy of attitude reconstruction, a factor that significantly influences the feasibility of Quantum Space Gravimetric (QSG) missions. We examine the specifications, strengths, and limitations of attitude, acceleration, position and inter-satellite distance sensors to combine them realistically in scenarios specific to quantum low-low satellite-to-satellite and gravity gradiometry missions relying on CAI instruments. We also analyse the classic counterparts, offering valuable insights into the conceptual mission configurations that benefit the most from CAI-based observations. Our findings contribute not only to the advancement of the use of CAI technology in future graviemtric missions but also to the broader understanding of the intricate interplay between cutting-edge measurement techniques and the supporting instrumentation required for their successful implementation.

This work is supported by the European Space Agency, under the project Quantum Space Gravimetry for monitoring Earth’s Mass Transport Processes (QSG4EMT), which has the general objectives to analyse future QSG mission architectures with ultimate goal to optimally exploit the performance of quantum sensors for retrieving temporal variations of Earth’s gravity field, evaluate the impact of mission configurations on the quality of the retrieved gravity field models and support the evolution of user requirements for future QSG missions.

How to cite: de Teixeira da Encarnacao, J., Siemes, C., Daras, I., Strangfeld, A., Zingerle, P., and Pail, R.: Towards a realistic modelling of gravimetric errors in future missions equipped with quantum sensors, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16325, https://doi.org/10.5194/egusphere-egu24-16325, 2024.