Union-wide
Community-led
Inter- and Transdisciplinary Sessions
Disciplinary sessions

G – Geodesy

Programme Group Chair: Annette Eicker

MAL18-G
Vening Meinesz Medal Lecture by Jeffrey T. Freymueller and G Division Outstanding ECS Award Lecture by Bramha Dutt Vishwakarma
Convener: Annette Eicker
DM8
Division meeting for Geodesy (G)
Convener: Annette Eicker

G1 – Geodetic Theory and Algorithms

Sub-Programme Group Scientific Officer: Annette Eicker

G1.1 EDI

Remarkable advances over recent years give evidence that geodesy today develops under a broad spectrum of interactions, including theory, science, engineering, technology, observation, and practice-oriented services. Geodetic science accumulates significant results in studies towards classical geodetic problems and also problems that only emerged or gained new interest, in many cases as a consequence of synergistic activities in geodesy and tremendous
advances in the instrumentations and computational facilities. In-depth studies progressed in parallel with investigations that mean a broadening of the traditional core of geodesy. The scope of the session is conceived with a certain degree of freedom, though the session is primarily intended to provide a forum for all investigations and results of a theoretical and methodological nature.

Within this concept, we seek contributions concerning problems of reference frames, gravity field studies, dynamics and rotation of the Earth, and positioning, but also presentations, which surpass the frontiers of these topics. We invite presentations illustrating the use of mathematical and numerical methods in solving geodetic problems, showing advances in mathematical modelling, estimating parameters, simulating relations and systems, using high-performance computations, and discussing methods that enable the exploitation of data essentially associated with new and existing satellite missions. Presentations showing mathematical and physical research directly motivated by geodetic need, practice and ties to other disciplines are welcome. In parallel to theory-oriented results also examples illustrating the use of new methods on real data in various branches of geodetic science and practice are very much solicited in this session.

Solicited authors:
Peiliang Xu
Convener: Michal Sprlak | Co-conveners: Zuzana Minarechová, Kevin GobronECSECS, Georgios Panou, Petr Holota
G1.2 EDI | Poster session

This session will focus on practical solutions of various formulations of geodetic boundary-value problems to yield precise local and regional high-resolution (quasi)geoid models. Contributions, including but not limited to, describing recent developments in theory, processing methods, downward continuation of satellite and airborne data, treatment of altimetry and shipborne data, terrain modeling, software development and the combination of gravity data with other signals of the gravity field for a precise local and regional gravity field determination are welcome. Of particular interest are topics dealing with the comparison of methods and results, the interpretation of residuals as well as geoid applications to satellite altimetry, oceanography, vertical datum realization and local and regional geospatial height registration.

Convener: Hussein Abd-Elmotaal | Co-conveners: Riccardo Barzaghi, E. Sinem InceECSECS, Xiaopeng Li, Georgios S. Vergos
G1.3 EDI

This session aims to showcase novel applications of data science and machine learning methods in geodesy.

In recent years, the exponential growth of geodetic data from various observation techniques has created challenges and opportunities. Innovative approaches are required to efficiently handle and harness the vast amount of geodetic data available nowadays for scientific purposes, for example when dealing with “big data” from Global Navigation Satellite System (GNSS) and Interferometric Synthetic Aperture Radar (InSAR). Likewise, numerical weather models and other environmental models important for geodesy come with ever-growing resolutions and dimensions. Strategies and methodologies from the fields of data science and machine learning have shown great potential not only in this context but also when applied to more limited data sets to solve complex non-linear problems in geodesy.

We invite contributions related to various aspects of applying methods from data science and machine learning (including both shallow and deep learning techniques) to geodetic problems and data sets. We welcome investigations related to (but not limited to): more efficient and automated processing of geodetic data, pattern and anomaly detection in geodetic time series, images or higher-dimensional data sets, improved predictions of geodetic parameters, such as Earth orientation or atmospheric parameters into the future, combination and extraction of information from multiple inhomogeneous data sets (multi-temporal, multi-sensor, multi-modal fusion), feature selection, super-sampling of geodetic data, and improvements of large-scale simulations. We strongly encourage contributions that address crucial aspects of uncertainty quantification, interpretability, and explainability of machine learning outcomes, as well as the integration of physical models into data-driven frameworks.

By combining the power of artificial intelligence with geodetic science, we aim to open new horizons in our understanding of Earth's dynamic geophysical processes. Join us in this session to explore how the fusion of physics and machine learning promises advantages in generalization, consistency, and extrapolation, ultimately advancing the frontiers of geodesy.

Convener: Benedikt Soja | Co-conveners: Maria KaselimiECSECS, Milad AsgarimehrECSECS, Sadegh ModiriECSECS, Alex SunECSECS
NP4.1 EDI

Time series are a very common type of data sets generated by observational and modeling efforts across all fields of Earth, environmental and space sciences. The characteristics of such time series may however vastly differ from one another between different applications – short vs. long, linear vs. nonlinear, univariate vs. multivariate, single- vs. multi-scale, etc., equally calling for specifically tailored methodologies as well as generalist approaches. Similarly, also the specific task of time series analysis may span a vast body of problems, including
- dimensionality/complexity reduction and identification of statistically and/or dynamically meaningful modes of (co-)variability,
- statistical and/or dynamical modeling of time series using stochastic or deterministic time series models or empirical components derived from the data,
- characterization of variability patterns in time and/or frequency domain,
- quantification various aspects of time series complexity and predictability,
- identification and quantification of different flavors of statistical interdependencies within and between time series, and
- discrimination between mere correlation and true causality among two or more time series.
According to this broad range of potential analysis goals, there exists a continuously expanding plethora of time series analysis concepts, many of which are only known to domain experts and have hardly found applications beyond narrow fields despite being potentially relevant for others, too.

Given the broad relevance and rather heterogeneous application of time series analysis methods across disciplines, this session shall serve as a knowledge incubator fostering cross-disciplinary knowledge transfer and corresponding cross-fertilization among the different disciplines gathering at the EGU General Assembly. We equally solicit contributions on methodological developments and theoretical studies of different methodologies as well as applications and case studies highlighting the potentials as well as limitations of different techniques across all fields of Earth, environmental and space sciences and beyond.

Co-organized by BG2/CL5/EMRP2/ESSI1/G1/GI2/HS13/SM3/ST2
Convener: Reik Donner | Co-conveners: Tommaso AlbertiECSECS, Giorgia Di CapuaECSECS, Simone BenellaECSECS, Nina Kukowski

G2 – Reference Frames and Geodetic Observing Systems

Sub-Programme Group Scientific Officer: Annette Eicker

G2.1 EDI

Precise orbit determination is of central importance for many applications of geodesy and earth science. The challenge is to determine satellite orbits in an absolute sense at the centimeter or even sub-centimeter level, and at the millimeter or even sub-millimeter level in a relative sense. Four constellations of GNSS satellites are available and numerous position-critical missions (e.g. altimetry, gravity, SAR and SLR missions) are currently in orbit. Altogether, outstanding data are available offering new opportunities to push orbit determination to the limit and to explore new applications.

This session aims to make accessible the technical challenges of orbit determination and modelling to the wider community and to quantify the nature of the impact of dynamics errors on the various applications. Contributions are solicited from, but not limited to, the following areas: (1) precise orbit determination and validation; (2) satellite surface force modelling; (3) advances in modelling atmospheric density and in atmospheric gravity; (4) advances in modelling earth radiation fluxes and their interaction with space vehicles; (5) analysis of changes in geodetic parameters/earth models resulting from improved force modelling/orbit determination methods; (6) improvements in observable modelling for all tracking systems, e.g. SLR, DORIS, GNSS and their impact on orbit determination; (7) advances in combining the different tracking systems for orbit determination; (8) the impact of improved clock modelling methods/space clocks on precise orbit determination; (9) advances in modelling satellite attitude; (10) simulation studies for the planned co-location of geodetic techniques in space mission GENESIS.

Convener: Adrian Jaeggi | Co-conveners: Alexandre CouhertECSECS, Jose van den IJssel, Oliver Montenbruck, Urs Hugentobler
G2.2

The Terrestrial Reference Frame (TRF) is critical for monitoring the Earth's rotation in space, as well as for many Earth science applications that need absolute positioning and precise orbit determination of near-Earth satellites. TRFs are determined by modeling space geodetic observations at a ground network of stations and require the estimation of a large number of parameters including station positions and Earth Orientation Parameters. Nowadays, the major limiting factors for a reliable interpretation of the observed quantities and consequently a resilient monitoring of global change phenomena are measurement biases, systematic errors caused by measurement electronics, as well as imperfect background models.
This session welcomes contributions that develop strategies to overcome systematics in space geodetic observing systems such as long-term mean range biases in SLR observations, gravitational deformation of VLBI antennas, GNSS phase center variations, local tie discrepancies in global TRF solutions, etc. This session also focuses on the handling of time in geodesy, delay-compensated time and frequency distribution, time transfer (via space-based atomic clocks and common ground clocks), systematic errors in measurement electronics, optical clocks and quantum sensing for geodetic applications. The integration of optical clocks in Geodesy provides novel opportunities and new challenges, while satellite missions like ACES provide the means to transfer time at unprecedented levels of accuracy.
The second objective of this session is to bring together contributions from individual technique services, space geodetic data analysts, ITRS combination centres and ITRF users, with a broad range of applications from geosciences to society, to discuss the results and scientific applications of ITRF2020 and other realizations. The determination of new local tie vectors at co-location sites, the assessment of observed non-linear station motions, including geocentre motion, through space geodetic techniques by comparison with physics-based deformation models is of particular interest. Furthermore, the handling of co-located instruments of individual techniques onboard satellite missions (space ties) for TRF realization is explored. In general, presentations evaluating the terrestrial reference frame, on new or improved combination strategies, or regarding any type of development that potentially improves future ITRF solutions are highly encouraged.

Solicited authors:
Karl Ulrich Schreiber
Convener: Xavier Collilieux | Co-conveners: Mathis Bloßfeld, Claudio Abbondanza, Susanne Glaser, Radosław ZajdelECSECS, Jan Kodet, Eva Hackmann
G2.3 EDI

High precision modern geodetic observations enable comprehensive monitoring of multiple spheres of the Earth. They record fingerprints of changes within the Earth System, providing crucial information to address major scientific issues, e.g., natural hazards, climate changes, global water cycles. Interpreting geodetic observations requires implementation of reference frames, analysis techniques and models with accuracy comparable to or exceeding the observations. Consequently, geodesy expanded its scope from just measuring geometry, gravity, and rotation of the Earth to understanding fingerprints recorded there and has become a key science to understand the Earth System for functioning and sustainability of our society. The Global Geodetic Observing System (GGOS) realizes the metrological basis for monitoring the Earth System. It is designed to unite individual geodetic observations and model them into one consistent frame with the highest precision available. We welcome contributions relevant to GGOS, particularly its scientific and social aspects, infrastructure, products, and activities of geodetic services.

Very Long Baseline Interferometry (VLBI) is a key contributor to the GGOS, primarily through the development and role-out of the VLBI Global Observing System (VGOS) by the International VLBI Service for Geodesy and Astronomy (IVS). VLBI stands apart as the sole method with the capability to establish and sustain the International Celestial Reference Frame (ICRF). The ICRF3 was constructed using VLBI data at the standard S/X frequencies, along with observations at K-band and X/Ka-band, making it the first multi-frequency frame. The backward compatibility with the running legacy VLBI network is to be considered as a tool to bridge nearly 40 years of legacy and last 4 years of VGOS observations. VGOS antennas were designed with two aims: to increase the measurement precision, from a cm-level to the GGOS goal of 1 mm; to increase the observational cadence, from 2-3 sessions per week to continuous observations. In this session we explicitly seek contributions to revisit the original goals and map the future VLBI contribution to GGOS. Besides this, we welcome the contributions dedicated to the satellite tracking with the fast VGOS antennas, an approach that promises to enhance and homogenize the reference frame determination.

Solicited authors:
Henryk Dobslaw
Convener: Kosuke Heki | Co-conveners: Martin Sehnal, Allison Craddock, Esther AzcueECSECS, Anastasiia WalentaECSECS, Minghui Xu, Aletha de Witt
G2.6 EDI

In recent years, we have observed steady progress in signals, services, and satellite deployment of Global Navigation Satellite Systems (GNSS). Consequently, modernizing existing GNSS systems and developing new constellations have moved us towards a new era of multi-constellation and multi-frequency GNSS signal availability. Meanwhile, the technology development provided high-grade GNSS user receivers to collect high rate, low noise, and multipath impact measurements. Also, recent extraordinary progress in low-cost GNSS chipsets, smartphones, and sensor fusion must be acknowledged. Such advancements boost GNSS research and catalyze an expansion of traditional satellite navigation to novel areas of science and industry. On one side, the developments stimulate a broad range of new GNSS applications. On the other side, they result in new challenges in data processing. Hence, algorithmic advancements are needed to address the opportunities and challenges in enhancing high-precision GNSS applications' accuracy, availability, interoperability, and integrity.
This session is a forum to discuss advances in high-precision GNSS algorithms and their applications in geosciences such as geodesy, geodynamics, seismology, tsunamis, ionosphere, troposphere, etc.
We encourage but do not limit submissions related to:
- Processing algorithms in high-precision GNSS,
- Multi-GNSS benefits for Geosciences,
- Multi-constellation GNSS processing and product standards,
- High-rate GNSS,
- Low-cost receiver and smartphone GNSS observations for precise positioning, navigation, and geoscience applications,
- Precise Point Positioning (PPP, PPP-RTK) and Real Time Kinematic (RTK),
- GNSS and other sensors (accelerometers, INS, etc.) fusion,
- GNSS products for high-precision applications (orbits, clocks, uncalibrated phase delays, inter-system and inter-frequency biases, etc.),
- Troposphere and ionosphere modeling with GNSS,
- CORS services for Geosciences (GBAS, Network-RTK, etc.),
- Precise Positioning of EOS platforms,
- GNSS for natural hazards prevention,
- Monitoring crustal deformation and the seismic cycle of active faults,
- GNSS and early-warning systems,
- GNSS reflectometry.

Convener: Jacek Paziewski | Co-conveners: Elisa Benedetti, Mattia Crespi, Jianghui Geng, Alvaro Santamaría-Gómez
G2.7 EDI | PICO

This session combines two key aspects of geoscience research. Firstly, the potential of global navigation satellite systems (GNSS) will be explored, with a focus on small and mass market devices. They are used in various geosciences such as geodesy, hydrology, meteorology and similar topics. Contributions deal with instrumentation, innovative applications, algorithms and sensor calibration.

Secondly, the session will address recent advances and future challenges in thermospheric and ionospheric research, with a focus on space weather modelling and prediction. We investigate the interconnected systems that influence total electron content (TEC), plasma density and thermospheric neutral density. To address these interrelations, impacts, and applications, the Global Geodetic Observing System (GGOS) Focus Area on Geodetic Space Weather Research was implemented into the structure of the International Association of Geodesy (IAG). All relevant research and contributions on solar-Earth interactions and the effects of space weather on TEC and electron density are encouraged.

This joint session clusters diverse contributions that highlight the challenges and opportunities in these dynamic areas and helps to understand the geophysical phenomena that shape our world.

Co-organized by GI1
Convener: Balaji Devaraju | Co-conveners: Tobias Kersten, Franziska KochECSECS, Jens-Andre Paffenholz, Ehsan Forootan, Claudia Borries, Maike SchumacherECSECS

G3 – Geodynamics and Earth Fluids

Sub-Programme Group Scientific Officer: Annette Eicker

G3.1

This session invites innovative Earth system and climate studies employing geodetic observations and methods. Modern geodetic observing systems have been instrumental in studying a wide range of changes in the Earth’s solid and fluid layers at various spatiotemporal scales. These changes are related to surface processes such as glacial isostatic adjustment, the terrestrial water cycle, ocean dynamics and ice-mass balance, which are primarily due to changes in the climate. To understand the Earth system response to natural climate variability and anthropogenic climate change, different time spans of observations need to be cross-compared and combined with several other datasets and model outputs. Geodetic observables are also often compared with geophysical models, which helps in explaining observations, evaluating simulations, and finally merging measurements and numerical models via data assimilation.

We look forward to contributions that:​

1. Utilize geodetic data from diverse geodetic satellites including altimetry, gravimetry (CHAMP, GRACE, GOCE and GRACE-FO, SWOT), navigation satellite systems (GNSS and DORIS) or remote sensing techniques that are based on both passive (i.e., optical and hyperspectral) and active (i.e., SAR) instruments.​

2. Cover a wide variety of applications of geodetic measurements and their combination to observe and model Earth system signals in hydrological, ocean, atmospheric, climate and cryospheric sciences.​

3. Show a new approach or method for separating and interpreting the variety of geophysical signals in our Earth system and combining various observations to improve spatiotemporal resolution of Earth observation products.​

4. Work on simulations of future satellite mission (such as MAGIC and NGMM) that may advance climate sciences.​

5. Work towards any of the goals of the Inter-Commission Committee on "Geodesy for Climate Research" (ICCC) of the International Association of Geodesy (IAG).​

We are committed to promoting gender balance and ECS in our session. With author consent, highlights from this session will be tweeted with a dedicated hashtag during the conference in order to increase the impact of the session.

Solicited authors:
Jessica Fayne
Co-organized by CL5/OS4
Convener: Bramha Dutt VishwakarmaECSECS | Co-conveners: Anna KlosECSECS, Benoit Meyssignac, Vincent HumphreyECSECS, Carmen Blackwood
G3.3 EDI

Accurate modeling and prediction of Earth rotation is important for geodesy, astronomy and navigation, and relates to the variability of the circulation of the fluid components of the planet. Over the past years geodetic observation systems have made significant advances in monitoring Earth rotational motion and its variability, which must be accompanied by an enhancement of theories and models.
We are interested in the progress in the theory of Earth rotation. We seek contributions that are consistent internally with the accurate observations at the mm-level, to meet the requirements of Global Geodetic Observing System and respond to IAG 2019 Res. 5 and IAU 2021 Res. B2. We invite presentations within the scope of the IAU/IAG JWG Improving Theories and Models of the Earth’s Rotation.
We welcome contributions that highlight new determinations and analyses of Earth Orientation Parameters (EOP), including combinations of different geodetic and astrometric observational techniques for deriving UT1/length-of-day variations and polar motion. We welcome discussions of EOP solutions in conjunction with a consistent determination of terrestrial and celestial frames, as tackled in the IAG/IAU/IERS JWG Consistent Realization of TRF, CRF and EOP. We are interested in the latest achievements in EOP forecasting, especially reports exploring the potential of innovative techniques in improving forecast accuracy.
We invite contributions of both the dynamical basis for links between Earth rotation, geophysical fluids, and other geodetic quantities, such as the Earth gravity field or surface deformation, and of explanations for the physical excitations of Earth rotation. Besides tidal influences from outside the Earth, the principal causes for variable EOP appear to be related to angular momentum exchange from variable motions and mass redistribution of the fluid portions of the planet.
We welcome contributions about the relationship between EOP variability and the variability in fluids due to climate variation or global change signals. Forecasts of these quantities are important especially for the operational determination of EOP and the effort to improve predictions is an important topic. We also welcome input on the modeling, variability, and excitations of the rotation of other planetary bodies.

Solicited authors:
Ki-Weon Seo
Convener: Justyna Śliwińska-BronowiczECSECS | Co-conveners: Sigrid Böhm, Alberto Escapa, David Salstein, Florian Seitz
G3.4 EDI

The dynamic response of the solid Earth to the waxing and waning of ice sheets and corresponding spatial and temporal sea-level changes is termed Glacial Isostatic Adjustment (GIA). This process, like solid Earth tides, oceanic load tide, other short-period surface loading (e.g., continental water), and normal-mode oscillations, causes surface deformation and changes in the gravity field, rotation, and stress state of the Earth. Different types of observational data, now standardized, help constrain highly sophisticated models of the Earth. They also serve as a tool to constrain the rheological properties of the Earth.

We aim to bring together researchers working on GIA, body tides, short-period loading problems, and normal modes with the broad goal of using these various processes to better understand the interior of the Earth and other planets across these wide temporal and spatial scales. This session is co-sponsored by the SCAR sub-committee INSTANT-EIS, Earth - Ice - Sea level, in view of instabilities and thresholds in Antarctica (https://www.scar.org/science/instant/home/).

Solicited authors:
Volker Klemann
Co-organized by CR5/GD7, co-sponsored by SCAR
Convener: Holger Steffen | Co-conveners: Hilary Martens, Hugo Boulze, Federico Daniel MunchECSECS, Anastasia ConsorziECSECS, Jun'ichi Okuno, Matthias O. WillenECSECS
HS6.5 EDI

This session focuses on the hydrogeodetic measurement of water bodies such as rivers, lakes, floodplains and wetlands, groundwater and soil. The measurements relate to estimating water levels, extent, storage and discharge of water bodies through the combined use of remote sensing and in-situ measurements and their assimilation in hydrodynamic models.

Monitoring these resources plays a key role in assessing water resources, understanding water dynamics, characterising and mitigating water-related risks and enabling integrated management of water resources and aquatic ecosystems.

While in situ measurement networks play a central role in the monitoring effort, remote sensing techniques provide near real-time measurements and long homogeneous time series to study the impact of climate change from local to regional and global scales.

During the past three decades, a large number of satellites and sensors has been developed and launched, allowing to quantify and monitor the extent of open water bodies (passive and active microwave, optical), the water levels (radar and laser altimetry), the global water storage and its changes (variable gravity). River discharge, a key variable of hydrological dynamics, can be estimated by combining space/in situ observations and modelling, although still challenging with available spaceborne techniques. Interferometric Synthetic Aperture Radar (InSAR) is also commonly used to understand wetland connectivity, floodplain dynamics and surface water level changes, with more complex stacking processes to study the relationship between ground deformation and changes in groundwater, permafrost or soil moisture.

Traditional instruments contribute to long-term water level monitoring and provide baseline databases. Scientific applications of more complex technologies like Synthetic Aperture Radar (SAR) altimetry on CryoSat-2, Sentinel-3A/B and Sentinel-6 missions are maturing, including the Fully-Focused SAR technique offering very-high along-track resolution. The launched SWOT mission will open up many new hydrology-related opportunities when the data is calibrated, validated and released. We also receive submissions of preparation studies for Sentinel-3 Next Generation and CRISTAL and other proposed missions such as Guanlan, HY-2 and SmallSat constellations such as SMASH, and covering forecasting.

Solicited authors:
Angelica Tarpanelli
Co-organized by G3
Convener: Jérôme Benveniste | Co-conveners: Stefania CamiciECSECS, Fernando Jaramillo, Karina Nielsen
NH6.4

Interferometric Synthetic Aperture Radar (SAR, InSAR) has boomed into an exceptionally potent tool for quantifying large-scale deformation with high spatial resolution. The last decade has witnessed a remarkable surge in the SAR satellite market, featuring various satellites like Sentinel-1, ALOS-2, and commercial counterparts. This wealth of SAR and InSAR results present a huge opportunity to improve our understanding of hazard processes across various temporal and spatial scales, including earthquakes, volcanic eruptions, landslides, glacier movements, underground fluid changes, sea-level rise, tsunamis, and more.
This session will explore innovative SAR/InSAR processing methodologies and illuminate fresh perspectives on the underlying physics governing these geohazards. We welcome contributions that encompass a wide range of topics, including but not limited to: (1) ingenious algorithms to mitigate SAR/InSAR errors, incorporating state-of-the-art tools such as deep learning; (2) advanced processing strategies for SAR big data; (3) natural hazard applications with SAR/InSAR and other complementary geophysical datasets like GNSS and seismic waveforms; (4) hazard assessments and disaster risk reduction in terms of vulnerability, capacity, and resilience.

Solicited authors:
Pablo J. Gonzalez,Romain Jolivet,Yosuke Aoki,John Elliott
Co-organized by G3
Convener: Lin ShenECSECS | Co-conveners: Jihong LiuECSECS, Jin FangECSECS, Yu JiangECSECS, Zhangfeng MaECSECS
TS3.1 EDI

Across the time scales, from earthquakes to earthquake cycle
The last decade has seen the accumulation of new observations about earthquakes with a level of detail never reach before. In parallel, methods have significantly improved in geophysics, geodesy, and in paleoseismology-geomorphology. Hence, on one hand the number of earthquakes with well-documented rupture process and deformation pattern has increased significantly. On the other hand, the number of studies documenting long time series of past earthquakes, including quantification of past deformation has also increased. In parallel, the modeling community working on rupture dynamics, including earthquake cycle is also making significant progresses. Thus, this session is the opportunity to bring together these different contributions to foster further collaboration between the different groups focusing all on the same objective of integrating earthquake processes into the earthquake cycle framework. In this session we welcome contributions documenting earthquake ruptures and processes, both for ancient events or recent events, such as the Turkey sequence of 2023 for example, from seismological, geodetic, or paleoseismological perspective. Contributions documenting deformation during pre-, post-, or interseismic periods, which are highly relevant to earthquake cycle understanding, are also very welcomed. Finally, we seek for any contribution looking at the earthquake cycle from the modeling perspective, especially including approaches mixing data and modeling.

Co-organized by G3/SM4
Convener: Y. Klinger | Co-conveners: Alice-Agnes Gabriel, Harsha Bhat, Magali RizzaECSECS

G4 – Satellite Gravimetry, Gravity and Magnetic Field Modeling

Sub-Programme Group Scientific Officer: Annette Eicker

G4.1 EDI

For more than two decades, satellite missions dedicated to the determination of the Earth's gravity field have enabled a wide variety of studies related to climate research as well as other geophysical or geodetic applications. Continuing the successful, more than 15 years long data record of the Gravity Recovery and Climate Experiment (GRACE, 2002-2017) mission, its Follow-on mission GRACE-FO, launched in May 2018, is currently in orbit providing fundamental observations to monitor global gravity variations from space. Regarding the computation of high-resolution static gravity field models of the Earth and oceanic applications, the Gravity field and steady-state Ocean Circulation Explorer (GOCE, 2009-2013) mission plays an indispensable role. Complementary to these dedicated missions, observations from other non-dedicated missions such as Swarm as well as satellite laser ranging (SLR) have shown to be of significant importance, either to bridge gaps in the GRACE/GRACE-FO time series or to improve gravity field models and scientific results derived thereof. The important role of satellite gravimetry in monitoring the Earth from space has led to various ongoing initiatives preparing for future gravity missions, including simulation studies, the definition of user and mission requirements and the investigation of potential measurement equipment and orbit scenarios.

This session solicits contributions about:
(1) Results from satellite gravimetry missions as well as from non-dedicated satellite missions in terms of
- data analyses to retrieve time-variable and static global gravity field models,
- combination synergies, and
- Earth science applications.
(2) The status and study results for future gravity field missions.

Convener: Christoph DahleECSECS | Co-conveners: Saniya BehzadpourECSECS, Ulrich Meyer, Christina StrohmengerECSECS
G4.2 EDI

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)”.

Solicited authors:
Christian Schubert
Convener: Marvin ReichECSECS | Co-conveners: Jürgen Müller, Daniele Carbone, Elske de Zeeuw - van Dalfsen, Sébastien MerletECSECS
G4.3 EDI

The session is dedicated to the processing and modelling of gravity and magnetic field data related to spatial and temporal variations at all scales. This includes studies on modern processing and interpretation methods (e.g. including machine learning) as well as forward and inverse modelling case studies. Of special interest are studies dedicated to the crustal or lithospheric structure by integrating gravity and magnetic methods with other geophysical data (e.g. petrophysics, seismic) or combining data from terrestrial, airborne and satellite missions.

Solicited authors:
Michael Field
Co-organized by EMRP2/GD6
Convener: Jörg Ebbing | Co-conveners: Carla Braitenberg, Alexandra Guy, Bart RootECSECS, Mikhail Kaban

G5 – Geodetic Monitoring of the Atmosphere

Sub-Programme Group Scientific Officer: Annette Eicker

G5.1 EDI

Geodesy contributes to atmospheric science by providing some of the essential climate variables of the Global Climate Observing System. Water Vapor (WV) is currently under-sampled in meteorological and climate observing systems. Obtaining more high-quality humidity observations is essential to weather forecasting and climate monitoring. The production, exploitation and evaluation of operational GNSS-Met for weather forecasting is well established in Europe due to 20+ years of cooperation between the geodetic community and the national meteorological services. Improving the skill of numerical weather prediction (NWP) models to forecast extreme precipitation requires GNSS products with a higher spatio-temporal resolution and shorter turnaround. Homogeneously reprocessed GNSS data (e.g., IGS repro3) have high potential for monitoring water vapor climatic trends and variability. With shortening orbit repeat periods, SAR measurements are a new source of information to improve NWP models. Using NWP data within real-time (RT) GNSS data analysis can initialize PPP algorithms, thus shortening convergence times and improving positioning. GNSS signals can be used for L-band remote sensing when Earth-surface reflected signals are considered. GNSS-R contributes to environmental monitoring with estimates of soil moisture, snow depth, ocean wind speed, sea ice concentration and has the potential to be used to retrieve near-surface WV.
We welcome, but not limit, contributions on:
•Estimates of the neutral atmosphere using ground- and space-based geodetic data and the use thereof in weather forecasting and climate monitoring
•Retrieval and comparison of tropospheric parameters from multi-GNSS, VLBI, DORIS and multi-sensor observations
•Now-casting, forecasting, and climate research using RT and reprocessed tropospheric products, employing numerical weather prediction and machine learning
•Assimilation of GNSS tropospheric products in NWP and in climate reanalysis
•Production of SAR tropospheric parameters and assimilation thereof in NWP
•Homogenization of long-term GNSS and VLBI tropospheric products
•Delay properties of GNSS signals for propagation experiments
•Exploitation of NWP data in GNSS data processing
•Techniques for soil moisture retrieval from GNSS data and for ground-atmosphere boundary interactions
•Detection and characterization of sea level, snow depth and sea ice changes, using GNSS-R
•Studying the atmospheric water cycle employing satellite gravimetry.

Co-organized by AS5
Convener: Rosa Pacione | Co-conveners: Maximilian Semmling, Kyriakos BalidakisECSECS, Henrik Vedel

G6 – General Sessions

Sub-Programme Group Scientific Officer: Annette Eicker

G7 – Short Courses

Sub-Programme Group Scientific Officer: Annette Eicker

SC5.2 EDI

What is the “Potsdam Gravity Potato”? What is a reference frame and why is it necessary to know in which reference frame GNSS velocities are provided? Geodetic data, like GNSS data or gravity data, are used in many geoscientific disciplines, such as hydrology, glaciology, geodynamics, oceanography and seismology. This course aims to give an introduction into geodetic datasets and presents what is necessary to consider when using such data. This 90-minute short course is part of the quartet of introductory 101 courses on Geodynamics 101, Geology 101 and Seismology 101.

The short course Geodesy 101 will introduce basic geodetic concepts within the areas of GNSS, gravity data analysis and coordinate transformations. In addition, we will talk about glacial isostatic adjustment, a process that is observed by several various geodetic data. We will also show short examples of data handling and processing using open-source software tools. Participants are not required to bring a laptop or have any previous knowledge of geodetic data analysis.

Our aim is to give you more background information on what geodetic data can tell us and what not. You won’t be a Geodesist by the end of the short course, but we hope that you are able to have gained more knowledge about the limitations as well as advantages of geodetic data. The course is run by scientists from the Geodesy division, and is aimed for all attendees (ECS and non-ECS) from all divisions who are using geodetic data frequently or are just interested to know what geodesists work on on a daily basis. We hope to have a lively discussion during the short course and we are also looking forward to feedback by non-geodesists on what they need to know when they use geodetic data.

Co-organized by G7/HS11
Convener: Rebekka SteffenECSECS | Co-conveners: Thomas Knudsen, Eva Boergens, Benedikt Soja
SC5.1 EDI

This short course aims to introduce non-geologists to the structural geological and petrological principles that are used by geologists to study system earth.

The data available to geologists is often minimal, incomplete, and representative only for part of the geological history. Besides learning the field techniques that are needed to take measurements and acquire data, geologists also need to develop a logical way of thinking to overcome these challenges and to solve this complex puzzle.

In this course we briefly introduce the following subjects:
1) Geology rocks: Introduction to the principles of geology.
2) Moving rocks: The basics of plate tectonics.
3) Breaking rocks: From lab experiments to natural examples.
4) Dating rocks: Absolute and relative dating of rocks.
5) Shaping rocks: Using the morphology of landscapes as tectonic constraints.
6) Q&A!

Our aim is not to make you the next specialist in geology, but we will try and make you aware of the challenges a geologist faces when they go out into the field. We will also address currently used methodologies for the collection of geological data, to give other earth scientists a feel for the capabilities and limitations of geological research.

This course is given by Early Career Scientists and forms a quintet with the short courses on ‘Geodynamics 101’, ‘Seismology 101’, ‘Tectonics 101’, and ‘Geodesy 101’. For this reason, we will also explain what kind of information we expect from the fields of geodynamics, seismology and geodesy, and we hope to receive input on the kind of information you could use from our side.

Co-organized by G7/GD11/TS9
Convener: Richard WesselsECSECS | Co-conveners: Veronica PeverelliECSECS, Silvia CrosettoECSECS, Anouk BeniestECSECS, David Fernández-BlancoECSECS
SC5.4 EDI

How do seismologists detect earthquakes? How do we locate them? Is seismology only about earthquakes? Seismology has been integrated into a wide variety of geo-disciplines to be complementary to many fields such as tectonics, geology, geodynamics, volcanology, hydrology, glaciology and planetology. This 90-minute course is part of the Solid Earth 101 short course series together with 'Geodesy 101', ‘Geodynamics 101’, and ‘Geology 101’ to better illustrate the link between these fields.

In ‘Seismology 101’, we will present an introduction to the basic concepts and methods in seismology. In previous years, this course was given as "Seismology for non-seismologists" and it is still aimed at those not familiar with seismology -- in particular early career scientists. An overview will be given on various methods and processing techniques, which are applicable to investigate surface processes, near-surface geological structures and the Earth’s interior. The course will highlight the role that advanced seismological techniques can play in the co-interpretation of results from other fields. The topics will include:
- the basics of seismology, including the detection and location of earthquakes
- understanding and interpreting those enigmatic "beachballs"
- the difference between earthquake risks and hazards
- an introduction to free seismo-live.org tutorials and other useful tools
- how seismic methods are used to learn about the Earth, such as for imaging the Earth’s interior (on all scales), deciphering tectonics, monitoring volcanoes, landslides and glaciers, etc...

We likely won’t turn you into the next Charles Richter in 90 minutes but would rather like to make you aware how seismology can help you in geoscience. The intention is to discuss each topic in a non-technical manner, emphasising their strengths and potential shortcomings. This course will help non-seismologists to better understand seismic results and can facilitate more enriched discussion between different scientific disciplines. The short course is organised by early career scientist seismologists and geoscientists who will present examples from their own research experience and from high-impact reference studies for illustration. Questions from the audience on the topics covered will be highly encouraged.

Co-organized by G7/GD11/NH12/TS9
Convener: Dinko SindijaECSECS | Co-conveners: Foivos KarakostasECSECS, Ana NapECSECS, Katinka TuinstraECSECS, Eleanor DunnECSECS
SC5.3

During this short course we will introduce the participants to the principles and application of analogue models in interpreting tectonic systems.

Tectonic processes act at different spatial and temporal scales. What we observe today in the field or via direct and indirect measurement is often just a snapshot of processes that stretch over hundreds or thousands of km, and take millions of years to unfold. Thus, it is challenging for researchers to interpret and recontrust the dynamic evolution of tectonic systems. Analogue modeling provides a tool to overcome this limitation, allowing for the physical reproduction of tectonic processes on practical temporal and spatial scales (Myr → hrs, km → cm/m). Of course, the reliability of analogue models is a function of the assumptions and simplifications involved, but still their usefulness in interpreting data is outstanding.

In this course we will go through the following outline:
- History of Analogue Modelling
- Model setups and Materials
- Model scaling
- Monitoring Techniques
- Interpreting Model Results
- Interactive Demonstration: Running a Model
- Q&A

The final aim of this short course will be to present analogue modeling as a valid technique to be applied side by side with observations and data from the real world to improve our interpretation of the evolution of natural tectonic systems. We also intend to inspire the course participants to develop and run their own analogue tectonic modeling projects, and to provide them with the basic skills, as well as directions to find the additional resources and knowledge required to do so.

Co-organized by G7/GD11/TS9
Convener: Frank ZwaanECSECS | Co-conveners: Ágnes KirályECSECS, Michael RudolfECSECS, Riccardo ReitanoECSECS
SC5.5

The main goal of this short course is to provide an introduction into the basic concepts of numerical modelling of solid Earth processes in the Earth’s crust and mantle in a non-technical manner. We discuss the building blocks of a numerical code and how to set up a model to study geodynamic problems. Emphasis is put on best practices and their implementations including code verification, model validation, internal consistency checks, and software and data management.

The short course introduces the following topics:
(1) The physical model, including the conservation and constitutive equations
(2) The numerical model, including numerical methods, discretisation, and kinematical descriptions
(3) Code verification, including benchmarking
(4) Model design, including modelling philosophies
(5) Model validation and subsequent analysis
(6) Communication of modelling results and effective software, data, and resource management

Armed with the knowledge of a typical numerical modelling workflow, participants will be better able to critically assess geodynamic numerical modelling papers and know how to start with numerical modelling.

This short course is aimed at everyone who is interested in, but not necessarily experienced with, geodynamic numerical models; in particular early career scientists (BSc, MSc, PhD students and postdocs) and people who are new to the field of geodynamic modelling.

Co-organized by G7/GD11/TS9
Convener: Fabio Crameri | Co-conveners: Luuk van Agtmaal, Andres Rodríguez Corcho, Xin Zhou, Nickolas Moccetti Bardi, Björn Heyn, Marcel Thielmann