Guest post

Gravity time series still reveal new insights

Gravity time series still reveal new insights






View of the Medicina observatory.

The site hosts a superconducting gravimeter (SG) installed in a dedicated building next to a piezometer. Local height variations  are monitored by means of two GPS stations, located at the end of the N-S segment of the “North Cross” radio telescope. The two GPS stations are about 30 m apart and are close to a VLBI antenna.



Geodetic observations have proven to provide a fundamental base for advances in Earth-system sciences, while simultaneously supporting critical societal applications such as navigation, land planning and disaster management.

However, the interpretation of geodetic records is far from being a trivial task. The available observables typically respond to multiple geophysical phenomena; in turn, these phenomena can span over various temporal and spatial scales and can involve mass transfer and energy fluxes between the different parts of the system Earth. Therefore, one of the most exciting challenges that geodesy is currently facing concerns recognizing the fingerprints of different geophysical processes in the available observations.

In our recent talk at the EGU General Assembly, we focused on results derived from 20 years of continuous height and gravity measurements acquired at Medicina, Italy. Gravity data are well-suited to illustrate the complex interplay between different processes because they embed the effects of both mass variations and crustal deformation. Our study aimed to characterize the different contributions to the gravity data and quantitatively assess the agreement between independent observing techniques.

Thanks to the wealth of data collected during all these years, we were able to conclude that the gravity behavior in Medicina is mostly governed by the natural land subsidence and by regional non-linear variations in terrestrial water storage. For the first time, we have managed to quantify the temporal variations of geo-technical phenomena controlling the soil response to variations in surface fluids. As these phenomena can induce damages to the walls of buildings such as, for example, residential structures, any improvement in their understanding has also a valuable societal impact. By carefully modeling all the relevant components, we were able to reproduce gravity data with an overall agreement in the order 10 nm/s^2.

The long-term and effective collaboration between the Department of Physics and Astronomy of the University of Bologna and the German Federal Agency for Cartography and Geodesy made this experiment possible. There have been many challenges to overcome during the journey, but the insights revealed after (the first!) twenty years of operation tell us about a successful geodetic story.


Edited by Katrin Bentel



Sara Bruni is the recipient of the Geodesy Division Outstanding Early Career Scientist Award 2018 and a post-doc researcher at the Department of Physics and Astronomy of the University of Bologna, Italy. Her research interests include the combination of space geodetic techniques for the realization of the ITRF, sea-level studies in the Mediterranean area and the separation of signals in gravity dataset. You can contact her at sara.bruni4@unibo.it.

EGU General Assembly – an adventure for newbies

EGU General Assembly – an adventure for newbies

One day in January, we heard it through the grapevine that we were supposed to submit abstracts to an event called EGU. So we asked ourselves: What exactly is EGU? Our colleagues told us: ‘EGU is a huge, international conference worth going. And you will have a lot of fun.’ So we submitted our abstracts and hoped for the best. Three months later, we entered the airport with a poster box and some of our colleagues. Immediately, the excitement started seeing at least 20 poster boxes on the same flight. But our flight got canceled. So, instead of joining the ‘Opening Reception’ in the evening, we practiced queuing (which was helpful later for coffee and beer at EGU) at the airport. Luckily, we got a new flight and finally arrived in Vienna late at night.

The next morning, slightly tired and after the first of many coffees of the week ahead, we entered the tube going to Kaisermühlen/VIC. It was amazing to see the huge crowd swarming to the conference center. When we were supposed to put up Kristin’s poster in the early morning on board X4.256, we realized the extent of EGU. The hall was incredibly huge and there were five more of them! Of course, orientation was no problem, since both of us are geodesists 😉

So we went two floors up to attend the first session with an incredibly long name and the letter combination ST3.5/EMRP4.33/G4.4. This weird abbreviation turned out to be a joined session of three divisions: Solar-Terrestrial Sciences (ST), Earth Magnetism & Rock Physics (ERMPS) and Geodesy (G). This was totally Kristin’s topic, but Kerstin left after the first oral presentation to make her way to a HS session (Hydrological Sciences). Sometimes it is really hard to decide where to go, since there are always plenty of interesting sessions at the same time (666 in total!).

When in the late afternoon the queues for beer and wine got really long (which we already knew from the airport), it was time for the poster session. It surprised us that presenting our research was a lot of fun as we gained new research ideas and met interested people. However, we felt very exhausted after the poster sessions due to the low signal-to-noise ratio (incredibly loud and incessant noise).

By the end of our first day, we were more or less familiar with thousands of new abbreviations related to the conference itself and also to different research areas, e.g. GW is either used as groundwater or gravity wave. And after this first day of confusion, the EGU-app and even twitter turned out to be really helpful to schedule our time.

During the week, we also learned to appreciate the name badges as they were sometimes really helpful, when you accidentally run into famous people in your research area, who you have never met before. While attending short courses like “Rhyme your research” or “Serious games for Natural Hazards”, we met people from other disciplines as well. To survive the amount of input, we spent highly needed breaks in the sun by the river. During the breaks or at dinner, it was also great to catch up with new and old friends from summer schools etc. BTW, the food in Vienna is absolutely stunning.

Furthermore, we totally loved the Imaggeo photo contest – the pictures we voted for actually belonged to the winning pictures. Another must-see – at least in geodesy division – was the medal lecture on Thursday evening.

We will definitely come back next year! And the first thing Kerstin installs on her new mobile, is Twitter.


Edited by Katrin Bentel


Kristin Vielberg is a PhD student at the Institute of Geodesy and Geoinformation at the University of Bonn, Germany. Her research is on force modeling of satellites with the aim of better understanding the coupling of the thermosphere and the ionosphere. You can contact her at vielberg@geod.uni-bonn.de and her twitter handle is @KManyMountain.


Kerstin Schulze is a PhD student at the Institute of Geodesy and Geoinformation at the University of Bonn in Germany. She studies the assimilation of multiple data sets, including satellite and in-situ observations, into hydrological models. You can contact Kerstin at schulze@geod.uni-bonn.de and her twitter handle is @KExploringEarth.

Review of the General Assembly by the Division President

Review of the General Assembly by the Division President

More than 15.000 participants with great presentations in 666 sessions (posters, PICOs, and orals) made the EGU General Assembly 2018 at the Austrian Convention Centre in Vienna a great success.
In the geodesy-led programme, we had 428 submissions, which were distributed to 19 oral blocks, 3 PICO sessions, and a series of poster sessions. We listened to exciting talks, starting with geodetic theory on Monday morning and ending with presentations on VLBI and SLR observations to artificial objects in space on Friday afternoon. The PICO sessions with 2-minute (“madness”) introductions are attracting increasing interest, and the poster sessions in the evening made EGU 2018 a good place for discussions and networking. (Hopefully, there will be faster access to coffee and beer next year.)

As a central element of its General Assembly, EGU offered a series of Union Sessions, Interdisciplinary Events, Great Debates, and Short Courses. I always appreciate this possibility of seeing a bigger picture of geosciences. At the Division level, a Geodesy Reception was organised for the first time at TU Wien Tuesday evening with a nice view over the city. This event was well received, although some fine-tuning in the organisation is required to be able to repeat it in 2019. Highlights in geodesy were certainly the presentations of the Vening Meinesz Medal to Markus Rothacher and the Outstanding Early Career Scientist Award to Sara Bruni. Congratulations!

I really would like to thank everybody (participants, authors, conveners, Division Officers, …) for their contributions and fellowship with EGU. You make the EGU General Assemblies an extremely valuable event for geodesy! I hope you enjoyed EGU 2018 – recommendations and feedback (positive and negative) is highly appreciated (email to g@egu.eu).

Looking forward to seeing you in Vienna in April 2019,
Johannes Böhm


So we produced this big pile of GIS data, what now?

So we produced this big pile of GIS data, what now?

We all know that easy access to data speeds up doing research. In this post, we will discuss how open GIS data can stimulate innovative ways of doing research in the field of geodesy and geosciences, considering first the benefits and challenges of open data.

Geodesy can benefit greatly from the open data movement and from open Geographic Information System (GIS) data. The reasons for this are two. First, open data, namely data freely usable, re-usable and re-distributable, promotes transparency, verifiability, encourages interdisciplinary studies, knowledge-exchange, etc. See also “13 Reasons for Open Publication of Geoscience Data”. Second, GIS allows the storage, manipulation, managing and analysis of topographic data. Hence, open GIS data is a powerful tool for geoscientists and geodesists who can conduct data-driven analyses like never before.

Yet, utilising open data in the geodesy field is often easier said than done. A recent Open Knowledge International’s report identified the main problems hindering the open data movement. These are: the very low discoverability of open data sources, which were rightfully defined as “hard or impossible to find”; the lack of interoperability of open data sources, often very difficult to be utilised; and the lack of a standardized open license, representing a legal obstacle to data sharing. These problems thus prevent open GIS data sources from being fully exploited for scientific advancements in geodesy.

Some initiatives have tried to address the problems above. OpenStreetMap, for instance, is a collaborative and voluntary project which utilises satellite data to create maps of the world. The EU launched Copernicus, a programme aimed at developing European information services based on satellite and in-situ data. These initiatives contribute to improve the findability of data, but do not address a crucial problem: how to reutilise GIS data to create applications, spurring innovative ways of conducting scientific research in geodesy. If apps based on GIS data were created and made available to geodesists, they could utilise these tools to conduct data-driven research, visualise topographic sources, collect more data, etc.

Open data aggregators could help address this issue. Aggregators have two main functions: data aggregation and integration. Aggregation consists of creating hubs where multiple data sources can be accessed for various purposes. Integration refers to linked data, namely data to which a semantic label (a name describing a variable) is attached to allow for the integration and amalgamation of different data sources (Mazzetti et al 2015, Hosen and Alfina 2016, Qanbari et al 2015, Knap et al 2012).  The integration function is precisely what renders data re-usable.



Below we present an aggregator particularly suited to the resolve the re-utilisation problems hindering GIS data: The European Network for Redistributing Geospatial Information to user Communities- Open Data (ENERGIC-OD). The ENERGIC-OD consortium, funded by the European Commission, launched a pan-European Virtual Hub (pEVH). This is a super-broker that automatically searches for open GIS data available online (i.e. GEOSS, INSPIRE, COPERNICUS data and new/existing, local/national Spatial Data Infrastructures or SDIs ), process it and renders it ready to use for app developers, facilitating open GIS data usage across Europe. The image below shows the pEVH’s brokering framework, including some examples of the datasets processed. The readers can access the pEVH today here.

To demonstrate the viability of the pEVH, ENERGIC-OD consortium developed 10 applications based on VH-brokered data. One of these apps, the Coastline Monitoring Application, constitutes an interesting and innovative development in the geoscience research world and provides an idea of what can be achieved with applications based on GIS data.

This app allows registered users to contribute directly to the study of coastlines, providing scientists and researchers with valuable information and observations. The application utilises the pEVH’s crowdsourcing functionality that allows people to produce data, in the form of images for example, which will be then checked and validated before being shared with the wider public. This app has thus a three-fold function of data generator, validator and sharer.

The Coastline Monitoring Application is just one example of what can be achieved with ENERGIC-OD and what this data broker can do for geosciences and geodesy. The pEVH has the potential to resolve issues of low discoverability, lack of interoperability and low re-usage burdening the open GIS data world. Additionally, thanks to its brokering features, any scientist with basic computer programming skills can extract and manipulate GIS data for app-development. These apps have the potential to be of great usefulness to geodesists. ENERGIC-OD can thus be a great facilitator of geoscience research. It is up to the wider scientific community to exploit its functionalities in innovative and meaningful ways.


Hosen, A. and Alfina, I. (2016). Aggregation of Open Data Information using Linked Data: Case Study Education and Job Vacancy Data in Jakarta. IEEE, pp.579-584.

Knap, T., Michelfeit, J. and Necasky, M. (2012). Linked Open Data Aggregation: Conflict Resolution and Aggregate Quality. IEEE 36th International Conference on Computer Software and Applications Workshops, pp.106-111.

Mazzetti, P., Latre, M., Bauer, M., Brumana, R., Brauman, S. and Nativi, S. (2015). ENERGIC-OD Virtual Hubs: a brokered architecture for facilitating Open Data sharing and use. IEEE eChallenges e-2015 Conference Proceedings, pp.1-11.

Qanbari, S., Rekabsaz, N. and Dustdar, S. (2017). Open Government Data as a Service (GoDaaS): Big Data Platform for Mobile App Developers. IEEE 3rd International Conference on Future Internet of Things and Cloud, pp.398-403.

Edited by Katrin Bentel and Roelof Rietbroek


Giuseppe Maio is a research assistant working on innovation at Trilateral Research. You can contact him at giuseppe.maio@trilateralresearch.com and his twitter handle is @pepmaio



Jedrzej Czarnota is a research analyst at Trilateral Research. He specialises in innovation management and technology development. You can contact Jedrzej at Jedrzej.czarnota@trilateralresearch.com and his twitter is @jedczar