Remarkable advances over recent years give an 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 theoretical and methodological nature.

Within this concept we seek contributions concerning problems of reference frames, gravity field studies, dynamics and rotation of the Earth, positioning, but also presentations, which surpass 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 also methods that enable to exploit 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.

The analysis of the Earth's gravity and magnetic fields is becoming increasingly important in geosciences. Modern satellite missions are continuing to provide data with ever improving accuracy and nearly global, time-dependent coverage. The gravitational field plays an important role in climate research, as a record of and reference for the observation of mass transport. The study of the Earth's magnetic field and its temporal variations is yielding new insights into the behavior of its internal and external sources. Both gravity and magnetic data furthermore constitute primary sources of information also for the global characterization of other planets. Hence, there continues to be a need to develop new methods of analysis, at the global and local scales, and especially on their interface. For over two decades now, methods that combine global with local sensitivity, often in a multiresolution setting, have been developed: these include wavelets, radial basis functions, Slepian functions, splines, spherical cap harmonics, etc. One purpose of this session is to provide a forum for exchange of research projects, whether related to forward or inverse modeling, theoretical, computational, or observational studies.
Besides monitoring the variations of the gravity and magnetic fields, space geodetic techniques deliver time series describing changes of the surface geometry, sea level change variations or fluctuations in the Earth's orientation. However, geodetic observation systems usually measure the integral effect. Thus, analysis methods have to be applied to the geodetic time series for a better understanding of the relations between and within the components of the system Earth. The combination of data from various space geodetic and remote sensing techniques may allow for separating the integral measurements into individual contributions of the Earth system components. Presentations to time frequency analysis, to the detection of features of the temporal or spatial variability of signals existing in geodetic data and in geophysical models, as well as to the investigations on signal separation techniques, e.g. EOF, are highly appreciated. We further solicit papers on different prediction techniques e.g. least-squares, neural networks, Kalman filter or uni- or multivariate autoregressive methods to forecast Earth Orientation Parameters, which are needed for real-time transformation between celestial and terrestrial reference frames.

In the past three decades high-precision GPS has been applied to support numerous applications in Geosciences. Currently, there are two fully operational Global Navigation Satellite Systems (GNSS), and two more are in the implementation stage. The new Galileo and BDS systems already provide usable signals, and both, GPS and GLONASS, are currently undergoing a significant modernization, which adds more capacity, more signals, better accuracy and interoperability, etc. Meanwhile, the huge technology development provided GNSS equipment (in some cases even at low-cost) able to collect measurements at much higher rates, up to 100 Hz, hence opening new possibilities. Therefore, on one side, the new 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, this, results in new problems and challenges in data processing which boost 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 related to activities of IAG SC4.4 'GNSS Integrity and Quality Control' and IAG-ICCT JSG T.32 'High-rate GNSS for Geosciences and Mobility'. It is a forum to discuss new developments in high-precision GNSS algorithms and applications in Geosciences; in this respect, contributions from other branches in Geosciences (geodynamics, seismology, tsunamis, ionosphere, troposphere, etc.) are very welcome.
We encourage, but not limit, submissions related to:
- Modeling and strategies in high-precision GNSS,
- Multi-GNSS benefit for Geosciences,
- Multi-GNSS processing and product standards,
- Inter-system and inter-frequency biases and calibrations,
- New or improved GNSS products for high-precision applications (orbits, clocks, UPDs, etc.),
- Precise Point Positioning (PPP, PPP-RTK),
- High-rate GNSS,
- GNSS and other sensors (accelerometers, INS, ecc.) integration for high-rate applications,
- Ambiguity resolution and validation,
- 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,
- High-precision applications for Geosciences,
- and more.

The Global Geodetic Observing System (GGOS) provides measurements of the time varying gravity, rotation, and shape of the Earth using geodetic and gravimetric instruments located on the ground and in space. These measurements need to be accurate to better than a part per billion in order to advance our understanding of the underlying processes that are causing the Earth's rotation, gravity, and shape to change. Mass transport in the global water cycle, sea level and climate change, and crustal deformation associated with geohazards are examples of particularly demanding applications of geodetic and gravimetric measurements. 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 should be a platform for discussing improvements to global geodetic observing systems including multidisciplinary approaches as well as for single contributions with high precision in a global network.

The Terrestrial Reference Frame is fundamental for monitoring Earth rotation in space and for all geoscience applications that require absolute positioning and precise orbit determination of artificial satellites. The goal of this session is to provide a forum to discuss reference systems theory, realization and applications in geosciences and society, with a special emphasis on the scientific applications of the International Terrestrial Reference Frame (ITRF), and namely the ITRF2014. Participants can discuss concerns not only related to the contributing technique services, but also all ITRF uses, ranging from local, regional to global applications. Contributions are sought from the individual technique services and various ITRF users, covering the complete range of topics, such as data analysis, parameter estimation and correction models. Of special interest is the assessment of the impact of non-linear station motions, e.g. periodic signals and post-seismic deformations. Contributions by the technique services related to the preparation of ITRF2020 focusing especially on identifying and mitigating technique systematic errors are highly appreciated. Contributions on local tie survey methodology are also welcome.

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. New constellations of GNSS satellites are currently being completed and numerous position-critical missions (e.g. altimetry, gravity, SAR and SLR missions) are currently in orbit. All together 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 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 geodetic products that describe the system Earth are of high quality, although the Global Geodetic Observing System (GGOS) goals of 1 mm accuracy and 0.1 mm/yr stability for the terrestrial reference frame, the Earth Orientation Parameters (EOPs) and the static and time-variable gravity field of the Earth are not yet fully reached. There are limiting factors that need to be detected, analyzed, and quantified. In this context, the usage of a sub-set of available observations only, degrading station equipment quality, limitations in the observing concepts and analysis and combination methods evoke the question whether and how the derived Earth system products can be improved.
In principle, there are two ways to investigate the best methods for improving geodetic products. (A) New strategies of handling, analyzing and combining the already existing space-geodetic observations need to be developed. (B) The existing observing infrastructure should be extended by new stations, new satellite missions, and new types of observations or new observing concepts. In the latter case, simulation studies are indispensable.
This session provides a platform for presentations of new strategies, new analysis methods and simulation studies seeking to improve the determination of Earth system parameters and geodetic products such as the Terrestrial and Celestial Reference Frame (TRF, CRF), EOPs, Earth’s gravity field, satellite orbits, as well as atmospheric key parameters. Presentations investigating approaches for reaching a better consistency between the individual parameters are highly welcomed, e.g., studies towards consistent estimation of the TRF, CRF and EOPs. Concerning consistency, novel approaches to achieve a consistent estimation of the three pillars of geodesy, i.e., geometry, orientation and gravity, are also welcomed. In addition we are seeking contributions focusing on alternative analysis concepts such as employing co-locations in space, clock ties, or atmospheric ties. Simulation studies investigating dedicated co-location satellites or novel observation methods (e.g. inter-satellite links or VLBI tracking of GNSS satellites) and their potential for improving the geodetic parameters are also invited. Many of the aspects mentioned above are brought together within the GGOS Standing Committee PLATO (Performance Simulations and Architectural Trade-Offs). Therefore, contributions related to the activities carried out within this group are also appreciated.

Over the past years significant progress has been made in the advancement of geodetic observation systems that resulted in largely improved accuracies of parameters related to the Earth's rotational motion and its variability. In this session we seek contributions in the following areas:
We are interested in the progress of theories of Earth rotation. We seek contributions on theoretical developments that are consistent internally and with the highly accurate observations at the mm-level, to meet the requirements of the IAG's Global Geodetic Observing System (GGOS). In particular, we invite presentations that address questions raised in the final report of the IAU/IAG joint working group, 'Theory of Earth Rotation and Validation'.
With respect to geodetic and astrometric observational techniques, we seek contributions that highlight new determinations of Earth Rotation Parameters (EOP) series and their analyses, including combinations of different observing techniques.
We also invite discussions 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 also of investigations leading to more detailed 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 the changing motions and mass redistribution of the fluid portions of the planet due to angular momentum exchange. Observations of the geophysical fluids (e.g., atmosphere, oceans) have achieved a new maturity in recent years. Independent observations include the results of recent gravity missions like GRACE.
We also welcome contributions about the relationship between EOP variability and current or potential variability in fluids due to climate variation or global change signals. Besides contemporary determination of the EOP and the related geophysical excitations, forecasts of these quantities are important especially for the operational determination of Earth orientation, e.g., for spacecraft navigation; the effort to improve predictions currently is a topic of strong interest. In this sense, the session is also open to contributions dealing with the operative use of Earth orientation in different applications.
In addition, we will welcome input on the modeling, characteristics, variability, and excitations of the rotation parameters of other planets or planetary bodies.

This session invites innovative Earth system and climate studies based on geodetic measuring techniques. Modern geodetic observing systems document a wide range of changes in the Earth’s solid and fluid layers at very diverging spatial and temporal scales related to processes as, e.g., glacial isostatic adjustment, the terrestrial water cycle, ocean dynamics and ice-mass balance. Different time spans of observations need to be cross-compared and combined to resolve a wide spectrum of climate-related signals. Geodetic observables are also often compared with geophysical models, which helps to explain observations, evaluate simulations, and finally merge measurements and numerical models via data assimilation.
We appreciate contributions utilizing 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. We welcome studies that 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. Any new approaches helping to separate and interpret the variety of geophysical signals are equally appreciated. Contributions working towards the newly established Inter-Commission Committee on "Geodesy for Climate Research" (ICCC) of the International Association of Geodesy (IAG) would be particularly interesting for this 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.

Satellite altimetry 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, seven 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 and operating in new orbits; the CryoSat-2/Sentinel-3 missions equipped with a Delay/Doppler altimeter, the Saral AltiKa mission carrying the first Ka band altimeter, and the recently launched photon counting laser altimeter on-board NASAs ICESat-2.

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

Low-lying coastal areas can be an early casualty to accelerating rates of sea-level rise, especially if land subsidence enhances such rates. More and more studies indicate that land subsidence due to natural and anthropogenic causes, including excessive groundwater extraction from coastal aquifers, peat oxidation due to surface water drainage through land reclamation, urbanization and agricultural use, as well as sediment starvation due to construction of dams and artificial levees, have caused damages to wetland ecosystems and increased flooding risk. While sea-level rise is a global issue and requires a global collaborative response, natural and anthropogenic coastal subsidence develops mainly at the local to regional scale, and its causes and severity vary substantially from place to place. Therefore, specific communities living on coastal areas can try to offset or reduced land subsidence.

The combination of geological and historical measurements and data from ongoing monitoring techniques is required to understand all drivers of coastal land motion and their contributions to past, present, and future subsidence. Research on coastal subsidence encompasses multidisciplinary expertise, requiring measuring and modeling techniques from geology, geodesy, natural hazards, oceanography, hydrogeology, and geomechanics. In this session, we want to bring together the expertise of all the involved disciplines. We invite contributions on all aspects of coastal subsidence research including recent advances on i) measurement through ground-based and remote sensing techniques, ii) numerical models, iii) their applicability to distinguish between the different drivers contributing to land subsidence, and iv) quantification of coastal hazards associated to relative sea-level rise. In particular, efforts towards characterizing human intervention on coastal land motion are welcome.

The growth and decay of the Polar Ice Sheet reshapes the solid Earth via isostasy and erosion. In turn, the shape of the bed exerts a fundamental control on ice dynamics as well as the position of the grounding line—the location where ice starts to float. A complicating issue is the fact that the Earth displays large spatial variations in rheological properties. These properties affect the timescale and strength of feedbacks between ice-sheet change and solid Earth deformation, and hence must be accounted for when considering the future evolution of the ice sheet. This session invites contributions discussing observations, analyses, and modelling of the coupling of the Solid Earth and glacial isostatic adjustment (GIA) and/or addressing the Earth properties from seismological, gravity, magnetic and heat-flow studies. Contributions related to both polar regions are welcomed.

Invited Speaker: Javier Fullea, Dublin Institute for Advanced Studies, Ireland

The WEGENER initiative was started in 1981 with the aim of creating an interdisciplinary forum supporting geodynamic studies by means of space and terrestrial geodetic techniques. Therefore, WEGENER promotes the establishment of a consistent framework leading from data acquisition, to data analysis, modeling and interpretation of the results. These activities provide key information to a broad range of phenomena that have critical implications for society, particularly in the field of natural hazards and climate change using techniques such as GNSS, InSAR, LiDAR, space/air/terrestrial gravimetry and ground-based geodetic observations.
In this session, we seek contributions that improve our understanding of geodynamical processes and crustal deformations at the local-to-global scale by means of geodetic techniques and innovative modeling approaches. Contributions showing the benefit of integrating geodetic and complementary geophysical, hydrological, geological, oceanographical and climatological information are also welcome. Relevant submissions may focus on the earthquake cycle, volcanic processes, sea-level changes, fluid redistributions and near surface motions such as landslides and subsidence. We also encourage contributions discussing the realization and outcomes of Supersites in the frame of the GEO initiative, as well as reports of the establishment of new geodetic networks in tectonically active areas.
Among other activities, the WEGENER will contribute to the joint IAG-IASPEI sub-commission on Seismo-Geodesy.

This session is open to science on the tides of the ocean, atmosphere and solid earth; on spatial scales from global to coastal, estuarine and river; and on all timescales. Tides can cause flooding, particularly in combination with storm surge, and tidal currents and water levels can be both a help and a hindrance to shipping and energy generation. There is a critical role for tides in ocean mixing and the cryosphere, and accurate tide models are required for the processing of remote sensing and satellite geodesy data.
We welcome presentations on progress in modelling of past, present, and future tides, assessment of the accuracy of tide models, novel methods for tide predictions, advances in instrumentation and data processing, new findings from the analysis of historical tide gauge data, and understanding of secular changes in tides due to sea-level change and other environmental forcing factors. We also invite submissions on tides of lakes and of other planets.
Déborah Idier of BGRM, the French Geological Survey, will give the invited presentation for this session, on the mechanisms of changes to tides on the European Shelf under sea-level rise.

The largest single source of uncertainty in projections of future global sea level is associated with the mass balance of the Antarctic Ice Sheet (AIS). In the short-term, it cannot be stated with certainty whether the mass balance of the AIS is positive or negative; in the long-term, the possibility exists that melting of the coastal shelves around Antarctica will lead to an irreversible commitment to ongoing sea level rise. Observational and paleoclimate studies can help to reduce this uncertainty, constraining the parameterizations of physical processes within ice sheet models and allowing for improved projections of future global sea level rise. This session welcomes presentations covering all aspects of observation, paleoclimate reconstruction and modeling of the AIS. Presentations that focus on the mass balance of the AIS and its contribution towards changes in global sea level are particularly encouraged.

Public information:
We will allocate five minutes of text-based discussion time to each abstract, as follows:

10:45-10:50 Introduction
10:50-10:55 Eelco Rohling
10:55-11:00 Jim Jordan
11:00-11:05 Javier Blasco
11:05-11:10 Emily Hill
11:10-11:15 Felicity McCormack
11:15-11:20 Gordon Bromley
11:20-11:25 Christian Turney
11:25-11:30 Tyler Pelle
11:30-11:35 Liyun Dai
11:35-11:40 Jun-Young Park
11:40-11:45 Christian Ohneiser
11:45-11:50 Catherine Beltran
11:50-11:55 Johannes Sutter
11:55-12:00 Nicolas Ghilain
12:00-12:05 Torsten Albrecht
12:05-12:10 Nicolas Jourdain
12:10-12:15 Christoph Kittel
12:15-12:20 Caroline van Calcar
12:20-12:25 James O'Neill
12:25-12:30 Thore Kausch

Seismic activity and crustal deformation are indicative of underlying plate tectonic and/or volcanic processes. Their connectedness is often non-linear and non-sequential. Seismic activity can result in crustal deformation in a tectonically or volcanically active region, while deformation arising from these forces can harness seismic potency. In isolation, seismic and geodetic (GNSS, InSAR) analysis potentially run the risk of delivering partial inferences, especially in compound geodynamic settings. Evidently, independently obtained results from seismic and geodetic observations are heavily reliant on the data type, methodology, model assumptions, and error estimations. In recent times, there have been several measures to jointly employ seismic and geodetic data to understand complex processes in aforementioned settings. Such studies have made significant contributions to modern and reliable data analysis practices. Therefore, this session aims to explore ongoing research that works towards arriving at comprehensive results from both ends of the spectrum; seismicity, a form of fast deformation, and its relationship with the slower geodetically measured deformation.

The current session invites presentation of research that simultaneously incorporates seismic and geodetic (GNSS, InSAR) techniques to investigate any given tectonic and/or volcanic setting. The study may include analyses of selected earthquakes and related deformation, comparison studies between seismic and geodetic data analysis, volcanic deformation and associated seismicity, and seismic cycle monitoring based on both seismology and geodesy. We also encourage studies using models (analytical or numerical) linking geodetic and seismic research, such as stress-strain models in volcanic and tectonic areas.

Invited Abstract:
Using Seismic and Geodetic Observations in a Simultaneous Kinematic Model of the 2019 Ridgecrest, California Earthquakes
Dara Goldberg1, Diego Melgar1, Valerie Sahakian1, Amanda Thomas1, Xiaohua Xu2, Brendan Crowell3, and Jianghui Geng4
1Department of Earth Sciences, University of Oregon, Eugene, Oregon, United States of America
2Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
3Department of Earth and Space Sciences, University of Washington, Seattle, Washington, United States of America
4Wuhan University, Wuhan, China

The US/German GRACE Follow-on (GRACE-FO) mission, successfully launched on 22 May 2018, prolongs the observations of the Gravity Recovery and Climate Experiment (GRACE). Satellite gravimetry missions such as GRACE, GRACE-FO and the Gravity field and steady-state Ocean Circulation Explorer (GOCE) have showed their fundamental impact for climate research studies and other geophysical or geodetic applications. The gravity field solutions can be complemented by data from other non-dedicated satellite missions like SWARM.
The great success of these missions clearly shows that global gravity variations can be at best monitored from space. Therefore, various initiatives are ongoing to prepare for future gravity missions: simulation studies have been performed, user and mission requirements have been defined and potential measurement equipment and orbit scenarios have been investigated.

This session solicits contributions about
(1) results from satellite gravimetry missions as well as from non-dedicated missions in terms of
- data analyses
- combination synergies
- Earth science applications
(2) status and study results for future gravity field missions.

Current developments in quantum physics will enable novel applications and measurement concepts in geodesy and Earth observation. In this Session, we will discuss new sensors and mission concepts that apply advanced techniques for the study of the gravitational field of the Earth on ground and in space. Terrestrial gravity anomalies will be determined by observing free-falling atoms (quantum gravimetry) gradually replacing the falling corner cubes. This technique can also be applied for future gradiometric measurements in space.
According to Einstein’s theory of general relativity, frequency comparisons of highly precise optical clocks connected by optical links give access to differences of the gravity potential (relativistic geodesy) for gravity field recovery and height determination. In future, precise optical could clouds be applied for defining and realizing height systems in a new way, and moreover, help to improve the accuracy of the International Atomic Time scale TAI. They are important for all space geodetic techniques as well as for the realization of reference systems and their connections.
Additionally, laser interferometry between test masses in space with nanometer accuracy – which has been realized in the GRACE-FO mission – belongs to these novel concepts, and in the future even more refined concepts (tracking a swarm of satellites, space gradiometry) will be realized.
Finally, changes in the gravity field can be derived from GNSS displacements which play an increasingly important role due to the relatively cheap and easy deployment of new GNSS receivers and the large number of available stations.
These techniques will open the door for a vast bundle of applications such as fast local gravimetric surveys and exploration, and the observation of Earth system processes from space with high spatial and temporal resolution.
We invite presentations to illustrate the principles and state of the art of those novel techniques and the application of the new methods for terrestrial and satellite geodesy (where local and global mass variations and surface deformations will be observed with substantially improved accuracy and resolution, variations that reflect changes in the Earth system), navigation and fundamental physics. We also welcome papers for further applications and invite contributions covering the theoretical description of the new methods, introducing novel theoretical concepts as well as new modelling schemes.

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, innovative applications of the results and data collected by modern satellite missions (e.g. GOCE, GRACE, Swarm), potential theory, as well as case histories.

Terrain gravimetry is a powerful geophysical tool that, through sensing changes in subsurface mass, can supply unique information on the dynamics of underground fluids, like water, magma, hydrocarbons, etc. This is critically important for energy industry (not just petroleum and natural gas, but also geothermal), resource management (particularly, with regard to water), and natural hazards (especially volcanoes).
Despite its potential, terrain gravimetry is currently underexploited, owing to the high cost of available instrumentation and the difficulty in using it under harsh environmental conditions and to the major challenge posed by retrieving useful information from gravity changes in noisy environments.
Major technology developments have recently occurred in instrumentation and methodology and are being demonstrated, opening up new perspectives to increase the capability of terrain gravimetry. On one hand, new types of sensors are being developed and ruggedized, expanding the measurement capabilities. On the other hand, methodologies and workflows are developed to exploit more efficiently hybrid networks of sensors. As an example, a recently funded H2020 project, called NEWTON-g, targets the development and field application of a “gravity imager” exploiting MEMS (relative) and quantum (absolute) gravimeters. These advancements will give new impulse to terrain gravimetry, thus helping its transition from a niche field into a cornerstone resource for geophysical monitoring and research. However, for this transition to succeed, technology developments must be complemented by constructive feedback from the gravimetry community
This session aims at bringing together instrument and tool developers and end-users of terrain gravimetry in a variety of fields, including, but not limited to, hydrology, volcanology and petroleum geology. We aim at discussing the state of the art of terrain gravimetry and the added value it provides with respect to other geophysical techniques, as well as the exciting opportunities offered by the new technologies under development.

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 emphasise 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 is under-sampled in the current meteorological and climate observing systems. Obtaining and exploiting more high-quality humidity observations is essential to weather forecasting and climate monitoring. The production, exploitation and evaluation of operational GNSS-Meteorology for weather forecasting is well established in Europe due to 20+ years of cooperation between the geodetic community and the national met services. Advancements in NWP models to improve forecasting of extreme precipitation require GNSS troposphere products with a higher resolution in space and shorter delivery times than are currently in use. Homogeneously reprocessed GNSS data 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 processing of GNSS observations can initialize PPP algorithms, shortening convergence times and improving positioning. GNSS signals can be used for L-band remote sensing when Earth-surface reflected signals are considered. GNSS-reflectometry 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 water vapor.
We welcome, but not limit, contributions on:
•Estimates of the neutral atmosphere using ground-based and space-based geodetic data, use of those estimates in weather forecasting and climate monitoring
•Multi-GNSS and multi-instruments approaches to retrieve and inter-compare tropospheric parameters
•Real-Time and reprocessed tropospheric products for now-casting, forecasting and climate
•Assimilation of GNSS tropospheric products in NWP and in climate reanalysis
•Production of SAR-based tropospheric parameters and use of them in NWP
•Methods for homogenization of long-term GNSS tropospheric products
•Studies of the delay properties of the GNSS signals for propagation experiments
•Usage of NWP data in GNSS data processing
•Techniques on retrieval of soil moisture from GNSS observations and of ground-atmosphere boundary interactions
•Estimates and methods using GNSS reflectometry for the detection and characterization of sea ice
•Usage of satellite gravity observations for studying the atmospheric water cycle.

In this session we search for contributions of general interest within the geodesy community which are not covered by other sessions. The session is open to all branches of geodesy and related fields of research. Additionally, it is linked to the PICOs G4.3 and G5.1 with presentations on ionosphere and gravity.

Space-based geodetic techniques including Interferometric Synthetic Aperture Radar (InSAR) and SAR-based change detection have become essential tools for high-quality mapping and analysis of the damage, change and deformation induced by natural and anthropogenic processes. Processing of these data have led to many new insights into understanding of geophysical and geological processes related to earthquakes, volcanic eruptions, landslides, sinkholes, floods, glaciers, and groundwater exploitation. They are also extremely useful for civil protection authorities for post-disaster response, detecting precursors of failure, and planning warning systems for areas prone to risk.
All scientists exploiting SAR/InSAR data to address challenges in the areas of the geosphere, cryosphere, biosphere and hydrosphere are cordially invited to contribute to this session. We welcome contributions from innovative processing algorithms, interpretation and modelling methods that are used for generating high-level products from SAR data for applications in earth and environmental sciences. Submissions are encouraged to cover a broad range of topics, which may include, but are not limited to, the following activities: SAR/InSAR algorithm development including cloud-based computing, deep learning and big data analysis, crustal deformation and earthquake cycle, landslides, volcanic processes, land subsidence, sinkholes, mining activities, infrastructure monitoring, flood monitoring, forest biomass and agriculture, glacier and ice dynamics, and permafrost

The distinction of a fluctuation from a long-term change in Earth processes is a key question in the assessment of the Earth's Climate change and in general geo- risk assessment. The distinction of a fluctuation from a steady change requires knowledge on the time variability of the signal and long term observations. Due to the decadal variability of sea level, reliable sea level trends can only be obtained after about sixty years of continuous observations. Reliable strain rates of deformation require a minimum of a decade of continuous data, due to the ambient factors leading to fluctuations. The session invites contributions that demonstrate the importance of long term geophysical, geodynamic, oceanographic and climate observatories. Advances in sensors, instrumentation, data analyses, and interpretations of the data are welcome, with the aim to stimulate a multidisciplinary discussion among those dedicated to the accumulation, preservation and dissemination of data over decadal time scales or beyond. With this session, we also would like to provide an opportunity to gather for representatives from observatories in Europe and also world-wide.

InSight landed on Mars on November 26th, 2018, bringing the first geophysical observatory to the surface of Mars. It attempts to constrain the interior structure of the planet and identify key physical processes that have shaped its evolution. At the time of the meeting, the instruments have been operating at full capacity for 14 months, or about half a Martian year. This session invites contributions from numerical modeling, experimental studies and data processing from various disciplines such as but not limited to geophysics, geology and geochemistry that aim to evaluate, interpret and complement the seismic and heat flow measurements, as well as rotational state, magnetic and atmospheric data of the InSight mission.
This interdisciplinary session will gather together results welcoming all research, whether part of the mission team or not.

Public information:
Additionally, a webcast will be held on Monday, May 4, 20:00 CEST (11:00 PST) to present the current status and scientific results of the InSight mission.

Join the webcast at
https://ethz.zoom.us/j/99691510985
Meeting-ID: 996 9151 0985

This session aims to bring together researchers working with big data sets generated from monitoring networks, extensive observational campaigns and detailed modeling efforts across various fields of geosciences. Topics of this session will include the identification and handling of specific problems arising from the need to analyze such large-scale data sets, together with methodological approaches towards semi or fully automated inference of relevant patterns in time and space aided by computer science-inspired techniques. Among others, this session shall address approaches from the following fields:
• Dimensionality and complexity of big data sets
• Data mining in Earth sciences
• Machine learning, deep learning and Artificial Intelligence applications in geosciences
• Visualization and visual analytics of big and high-dimensional data
• Informatics and data science
• Emerging big data paradigms, such as datacubes