In recent years we have witnessed notable progress in signals, services, and satellite deployment of Global Navigation Satellite Systems (GNSS). Modernizing operational GNSS systems and developing new constellations have moved us towards a new stage of multi-constellation and multi-frequency observations. Meanwhile, the technology development provided high-grade GNSS equipment to collect measurements at much higher rates, up to 100 Hz, of lower noise and multipath impact. Moreover, the recent progress in low-cost GNSS chipsets catalyzes an expansion of traditional satellite navigation to novel areas of science and industry. Therefore, on one side, the developments in GNSS stimulate a broad range of new applications for solid and fluid Earth investigations, both in post-processing and in real-time. On the other side, such progress results in further problems and challenges in data processing, which boosts GNSS research. Algorithmic advancements are needed to address the opportunities and challenges in enhancing the accuracy, availability, interoperability, and integrity of high-precision GNSS applications.
This session is a forum to discuss advances in high-precision GNSS algorithms and their applications to Geosciences. Contributions from other branches of Geoscience, such as geodynamics, seismology, tsunamis, ionosphere, troposphere, etc., are also welcome.
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,
- Precise Positioning for natural hazards prevention,
- Monitoring crustal deformation and the seismic cycle of active faults,
- GNSS and early-warning systems,
- GNSS reflectometry.

This session aims to showcase novel mathematical methods in geodesy, including enhancements of conventional statistical approaches as well as the application of machine learning techniques. In this regard, two areas that have seen significant developments in recent years are the analysis of geodetic time series and potential field data.

Modern satellite missions measuring the Earth's gravity and magnetic fields such as GRACE-FO and SWARM are continuing to provide data with ever improving accuracy and resolution. Hence, there continues to be a need to develop new methods of analysis, at the global and local scales, and especially on their interface. Furthermore, space geodetic techniques, including GNSS, deliver time series describing changes in the Earth system, such as the surface geometry, sea level change variations or fluctuations in the Earth's orientation. Geodetic observation systems usually measure the integral effect, whereas the aim is typically to understand the individual contributions of the Earth’s sub-components. In general, the amount of data from geodetic observation techniques has increased significantly in past decades. Innovative approaches are required to efficiently handle and harness the vast amount of geodetic data available nowadays for scientific purposes.

We invite contributions that address new mathematical developments in the analysis of potential field data and geodetic time series, and the application of machine learning techniques in general. Improved potential field data analysis may result from the application of wavelets, radial basis functions, Slepian functions, splines, spherical cap harmonics, etc. Time series analysis could benefit from new developments in the area of time-frequency analysis, detection of features of the spatio-temporal variability of signals, as well as signal separation techniques. The application of machine learning shows significant potential for automated processing of geodetic data, pattern and anomaly detection, combination and extraction of information from multiple inhomogeneous data sets, feature selection and sensitivity analysis, super-sampling of geodetic data, and improvements of large-scale simulations. Especially encouraged are contributions that discuss the uncertainty quantification, interpretability and explainability of results from machine learning algorithms, as well as the integration of physical modeling into data-driven frameworks.

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 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 it is primarily intended to provide a forum for all investigations and results of theoretical and methodological nature.

We welcome contributions concerning problems of reference frames, gravity field studies, dynamics and rotation of the Earth, positioning, but also presentations surpassing frontiers of these topics. We invite presentations illustrating the use of mathematical and numerical methods in solving geodetic problems, showing advances in mathematical modeling, estimating parameters, simulating relations and systems, using high-performance computations, and discussing methods for exploiting data of 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.

Part of the session will focus on the practical solution of various formulations of geodetic boundary-value problems to yield precise local and regional high-resolution (quasi)geoid models. Contributions describing recent developments in theory, processing methods, downward continuation of satellite & 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. Topics such as the comparison of methods and results, the interpretation of residuals and geoid applications to satellite altimetry, oceanography, vertical datums & local and regional geospatial height registration are of a special interest.

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.

The Terrestrial Reference Frame (TRF) is critical for monitoring the Earth's rotation in space, as well as for many geoscientific applications that need absolute positioning and exact orbit determination of near-Earth artificial satellites. Its new realization, the ITRF2020 has been released based on the combination of DORIS, GNSS, SLR, and VLBI station coordinate time series provided by the IAG/IERS Technique Services.
The objective of this session is to bring together contributions from individual Technique Services, space geodetic data analysts, ITRS combination centres and all 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 assessment of observed non-linear, and particularly periodic, station motions through space geodetic techniques by comparison with physics-based deformation models is of particular interest. Moreover, contributions to geocenter motion determination are encouraged. Finally, contributions that focus on identifying and mitigating technique-related systematic errors as well as different combination strategies, e.g., space and tropospheric ties are encouraged because they may potentially enhance future ITRF solutions.

The Global Geodetic Observing System (GGOS) provides measurements of the gravity, rotation, and shape of the Earth using space and terrestrial geodetic techniques. These measurements must be accurate to better than a part per billion in order to advance our understanding of the underlying processes responsible for temporal changes in the Earth's rotation, gravity, and shape. Demanding applications of geodesy include mass transport in the global water cycle, sea level and climate change, and crustal deformation associated with geohazards. All these measurements require a common reference with the same precision, like the terrestrial reference frame and the unified height system. GGOS is designed to unite the individual observations and model into one consistent frame with the highest precision available. This session welcomes contributions on topics relevant to GGOS, particularly those related to its scientific and social aspects, geodetic infrastructure, observations/products, and activities of services.
This year, a special focus will be reserved to accurate modelling and predictions of Earth rotation.
We are interested in reports on the progress in the theory of Earth rotation as well as in studies that highlight new determinations, analyses, and predictions of Earth Orientation Parameters (EOP), including combinations of different geodetic and astrometric observations 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. We invite contributions investigating the dynamical basis for links between Earth rotation, geophysical fluids, and other geodetic quantities (Earth gravity field, surface deformation...), and explanations for the physical excitations of Earth rotation. Finally, given the relevance of EOP predictions for the operational determination of Earth orientation, we are particularly interested in results from the 2nd EOP Prediction Comparison Campaign and in contributions exploring the potential of innovative techniques, such as the use of artificial intelligence.

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), 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 SWOT and GRACE-2) 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.

Glacial Isostatic Adjustment (GIA) describes the dynamic response of the solid Earth to the waxing and waning of ice sheets and corresponding spatial and temporal sea-level changes, which causes surface deformation and changes in the gravity field, rotation, and stress state of the Earth. The process of GIA is mainly influenced by the ice-sheet evolution and solid Earth structure, and in turn influences other components of the Earth system such as the cryosphere (e.g., ice sheets) and hydrosphere (e.g., ocean and sea level). A large set of observational data (e.g., relative sea level, GNSS measurements, tide gauges, terrestrial and satellite gravimetry, satellite altimetry, glacially induced faults) that can be used to constrain highly sophisticated GIA models is available nowadays in standardized form, which will further help in investigating the ice-sheet and sea-level evolution histories and rheological properties of the Earth, and understanding the interactions between ice sheets, the solid Earth and sea levels.

This session invites contributions discussing observations, analysis, and modelling of GIA and its effects on the Earth system across a range of spatial and timescales. Examples include, but not limited to, geodetic measurements of crustal motion and gravitational change, GIA modelling with complex Earth models (e.g., 3D lithosphere and/or viscosity, non-linear rheologies), GIA-induced global, regional and local sea-level changes, coupled GIA-ice sheet modelling for investigating past and future ice sheets/shelves changes and associated sea-level changes, glacially triggered faulting as well as the Earth’s (visco-)elastic response to present-day ice-mass changes. We also welcome abstracts that address GIA effects on nuclear waste repositories, groundwater distribution and migration of carbon resources. 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/ and PALMOD, the German Climate Modeling Initiative https://www.palmod.de.

Tides play a pervasive role in the Earth system. They supply mechanical energy to fuel ocean turbulent dissipation and mixing, which in turn sustain the meridional overturning circulation, they modulate ice-shelf basal melt rates, cause coastal erosion, affect marine ecosystems and ocean biogeochemistry, and may raise or lower the sea-level baseline for storm surges. There are also tides in the atmosphere, which can impart terrestrial weather and climate variability well into the geospace. Looking down, precise measurements of solid Earth tides and the closely related ocean tidal loading are a unique means of probing Earth's interior and the frequency dependence of viscoelastic properties. Moreover, corrections for ocean tide signals underlie many Earth observation applications, including analyses of satellite altimetry and gravimetry data to determine sea level and ocean mass changes on local to global scales.

This session is open to research on any aspect of tides in the ocean, atmosphere, and solid Earth. We invite contributions on progress in numerical and empirical modelling of surface and internal tides in the ocean, the implications of internal tides for mixing and ocean circulation, modelling and observation of tidal variability, tidal analysis, atmosphere-ionosphere coupling through tides, and research into the role of tides in shaping Earth's ability to host life. Contributions may highlight tidal processes at any spatial and temporal scale on Earth and other planets.

The session deals with the documentation and modelling of the tectonic, deformation and geodetic features of any type of volcanic area, on Earth and in the Solar System. The focus is on advancing our understanding on any type of deformation of active and non-active volcanoes, on the associated behaviours, and the implications for hazards. We welcome contributions based on results from fieldwork, remote-sensing studies, geodetic and geophysical measurements, analytical, analogue and numerical simulations, and laboratory studies of volcanic rocks.
Studies may be focused at the regional scale, investigating the tectonic setting responsible for and controlling volcanic activity, both along divergent and convergent plate boundaries, as well in intraplate settings. At a more local scale, all types of surface deformation in volcanic areas are of interest, such as elastic inflation and deflation, or anelastic processes, including caldera and flank collapses. Deeper, sub-volcanic deformation studies, concerning the emplacement of intrusions, as sills, dikes and laccoliths, are most welcome.
We also particularly welcome geophysical data aimed at understanding magmatic processes during volcano unrest. These include geodetic studies obtained mainly through GPS and InSAR, as well as at their modelling to imagine sources.

The session includes, but is not restricted to, the following topics:
• volcanism and regional tectonics;
• formation of magma chambers, laccoliths, and other intrusions;
• dyke and sill propagation, emplacement, and arrest;
• earthquakes and eruptions;
• caldera collapse, resurgence, and unrest;
• flank collapse;
• volcano deformation monitoring;
• volcano deformation and hazard mitigation;
• volcano unrest;
• mechanical properties of rocks in volcanic areas.

During the last decades, 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 recent or ancient events, 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.

Inverse Problems are encountered in many fields of geosciences. One class of inverse problems, in the context of predictability, is assimilation of observations in dynamical models of the system under study. Furthermore, objective quantification of the uncertainty during data assimilation, prediction and validation is the object of growing concern and interest.
This session will be devoted to the presentation and discussion of methods for inverse problems, data assimilation and associated uncertainty quantification throughout the Earth System like in ocean and atmosphere dynamics, atmospheric chemistry, hydrology, climate science, solid earth geophysics and, more generally, in all fields of geosciences.
We encourage presentations on advanced methods, and related mathematical developments, suitable for situations in which local linear and Gaussian hypotheses are not valid and/or for situations in which significant model or observation errors are present. Specific problems arise in situations where coupling is present between different components of the Earth system, which gives rise to the so called coupled data assimilation.
Of interest are also contributions on weakly and strongly coupled data assimilation - methodology and applications, including Numerical Prediction, Environmental forecasts, Earth system monitoring, reanalysis, etc., as well as coupled covariances and the added value of observations at the interfaces of coupled models.
We also welcome contributions dealing with algorithmic aspects and numerical implementation of the solution of inverse problems and quantification of the associated uncertainty, as well as novel methodologies at the crossroad between data assimilation and purely data-driven, machine-learning-type algorithms.

For about two decades now, 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.

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 possibilities 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 the application to various fields 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. We also 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.).
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 the H2020 project “New Tools for Terrain Gravimetry (NEWTON-g)”.

Gravity and magnetic field data contribute to a wide range of geo-scientific research, from imaging the structure of the earth and geodynamic processes (e.g. mass transport phenomena or deformation processes) to near surface investigations. The session is dedicated to contributions related to spatial and temporal variations of the Earth gravity and magnetic field at all scales. Contributions to modern potential field research are welcome, including instrumental issues, data processing techniques, interpretation methods, machine learning, innovative applications of the results and data collected by modern satellite missions (e.g. GOCE, GRACE, Swarm), potential theory, as well as case histories.

Swarm is ESA's first constellation mission for Earth Observation and consists of three identical spacecraft launched on 22 November 2013. Each of the three Swarm satellites performs high-precision and high-resolution measurements of the strength, direction and variation of the magnetic field, accompanied by precise navigation, accelerometer, plasma and electric field measurements. Each satellite is equipped with magnetic sensors, measuring a combination of various contributing sources: the Earth’s core field, magnetised rocks in the lithosphere, external contributions from electrical currents in the ionosphere and magnetosphere, currents induced by external fields in the Earth’s interior and a contribution produced by the oceans. This session invites contributions illustrating the achievements of Swarm for investigating all types of Earth and near-Earth processes, as well as contributions describing synergies with other missions and ongoing initiatives towards designing innovative new magnetic field measurements missions.

The term space weather indicates physical processes and phenomena in space caused by the radiation of energy mainly from the Sun. Solar and geomagnetic storms can cause disturbances in positioning, navigation and communication; coronal mass ejections (CME) can affect serious disturbances and in extreme cases damages or even destruction of modern infrastructure. The ionosphere and the thermosphere are parts of a physically coupled systems ranging from the Earth surface to the Sun including the magnetosphere and the lower atmosphere. Therefore, conducting detailed investigations on governing processes in the solar-terrestrial environment have key importance to understand the spatial and temporal variations of ionospheric and thermospheric key parameters such as the total electron content (TEC) and the plasma density of the ionosphere, as well as the thermospheric neutral density, which are influencing the orbits of Low-Earth orbiting (LEO) satellites. To address all these interrelations and impacts, 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).

This session will address recent progress, current understanding, and future challenges of thermospheric and ionospheric research including the coupling processes. Special emphasis is laid on the modelling and forecasting of space weather time series, e.g. EUV-, X-ray radiation and CMEs, and their impact on VTEC and electron density. We encourage further contributions to the dynamo electric field, the variations of neutral and ion compositions on the bottom and top side of the ionosphere, atmospheric gravity waves and TIDs. Furthermore, we appreciate contributions on the wind dynamo, electrodynamics and disturbances, including plasma drift, equatorial spread F, plasma bubbles, and resultant scintillation.

Another main topic is global and regional high-resolution and high-precision modelling of VTEC and the electron density based on empirical, analytical or physical data assimilation approaches, which are designed for post-processing or (near) real-time purposes.

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.

In this session we welcome contributions of general interest within the geodesy community. The session is open to all branches of geodesy and related fields of research.

A specific part of the session will focus on the topic of satellite altimetry, which provides the possibility to observe key parts of the hydrosphere, namely the ocean, ice, and continental surface water from space. Since the launch of Topex/Poseidon in 1992, the applications of altimetry have expanded from the open oceans to coastal zones, inland water, land, and sea ice. Today, several missions are in orbit, providing dense and near-global observations of surface elevation and several other parameters. Satellite altimetry has become an integral part of the global observation of the Earth‘s system and changes therein.

In recent years, new satellite altimetry missions have been launched carrying new instruments; the CryoSat-2, Sentinel-3, and Sentinel-6 missions equipped with a Delay/Doppler altimeter, the Saral AltiKa mission carrying the first Ka-band altimeter, and the photon-counting laser altimeter onboard NASA's ICESat-2. Further, new orbits with high inclination and long-repeat time are used for CryoSat-2 and ICESat-2.

Fully exploiting this unprecedented availability of observables will enable new applications and results but also require novel and adapted data analysis methods.
Across the different applications for satellite altimetry, the data analysis and underlying methods are similar and knowledge exchange between the disciplines has been proven to be fruitful.
In this multidisciplinary altimetry session, we, therefore, invite contributions that discuss new methodologies and applications for satellite altimetry in the fields of geodesy, hydrology, cryosphere, oceanography, and climatology.
Topics of such studies could for example be (but are not limited to); the creation of robust and consistent time series across sensors, validation experiments, a combination of radar and laser altimetry for e.g. remote sensing of snow, classification of waveforms, application of data in a geodetic orbit, retracking, or a combination with other remote sensing data sets.

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 and gravity data analysis. In particular, we will talk about:
- GNSS data analysis
- Reference frames
- Gravity data analysis
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.

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 ‘Geodynamics 101 (A & B)’ 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.

This 90-minute short course aims to introduce non-geologists to structural geological and petrological principles, which are used by geologists to understand system earth.

The data available to geologists is often minimal, incomplete and representative for only part of the geological history. Besides learning field techniques that are needed to take measurements and acquire data, geologists also need to develop a logical way of thinking to overcome these data gaps and arrive at an understanding of system earth. There is a difference between the reality observed in the field and the geological models that are used to tell the story.

In this course we briefly introduce the following subjects:
1) Geology rocks: Introduction to the principles of geology.
2) Collecting rocks: The how, what, and pitfalls of onshore and offshore geological data acquisition.
3) Failing rocks: From structural field data to (paleo-)stress analysis.
4) Dating rocks: Absolute and relative dating of rocks using microstructural, petrological and geochronological methods.
5) Shaping rocks: The morphology of landscapes as tectonic constraints
6) Crossover rocks: How geology benefits from geodynamic, seismological and geodetic research, and vice-versa.
7) Q&A!

Our aim is not to make you the next specialist in geology, but we would rather try and make you aware of the challenges a geologist faces when they go out into the field. In addition, currently used methodologies and their associated data quality are addressed 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 quartet with the short courses on ‘Geodynamics 101’, ‘Seismology 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.

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.