Onsala Space Observatory is an internationally established geodetic fundamental station. We measure and study many global geodynamic phenomena, that is, we study how the Earth changes.
Space geodesy and geodynamics
Onsala Space Observatory is an internationally established geodetic fundamental station. We measure and study many global geodynamic phenomena, that is, we study how the Earth changes. That means that we do research on Earth rotation, reference systems, plate tectonics, land uplift, gravity changes, Earth and oceanic tides, earthquakes, and water vapour in the atmosphere. For the observations we use radio telescopes (the Very Long Baseline Interferometry, VLBI, technique), global navigation satellite systems (GNSS), remote sensing satellites, gravimeters, microwave radiometers, and tide gauges. There is also a seismometer, belonging to the Swedish National Seismic Network operated by Uppsala University, located at the observatory.
For computing facilities, see the National Facility Computing Infrastructure (NaFCI).
Contact person for Earth science activities
Rüdiger Haas
Email: rudiger.haas@chalmers.se, Phone: +46 31-772 5530 (see also contact persons for the different instruments)
See also the web site of the Space Geodesy and Geodynamics unit at the Department of Space, Earth and Environment.
Facilities for Earth sciences are described here (see links in the left column above).
Geodetic VLBI
see separate page
GNSS
see separate page
Gravimeter
A permanently operating superconducting gravimeter is in operation at Onsala Space Observatory since June 2009. The main purpose of the facility is to be seen in conjunction with projects that determine gravity change in Fennoscandia, e.g. the Nordic Geodetic Commission's Working Group for Geodynamics. A dominating effect of gravity change in the form of a secular trend is for instance related to the post-glacial isostatic adjustment, an after-effect of the latest great ice sheet in the Pleistocene and its disappearance about 10,000 years ago.
The superconducting gravimeter can monitor temporal changes of gravity and thus provide visiting teams operating absolute gravimeters (free-falling prisms) with measurements of perturbations. These perturbations relate most often to the changing ground water masses near the observing point. But also the attraction and loading effects of the - coupled - system atmosphere and ocean are fairly complicated at the near-by coast of Kattegat.
For more information: see the web site of the superconducting gravimeter.
Contact person:
Maxime Mouyen
Email: maxime.mouyen@chalmers.se, Phone: +46 31-772 5549
Microwave radiometry
see separate page
Seismometer
A seismometer belonging to Det svenska nationella seismiska nätet (SNSN) is located at Onsala Space Observatory. For more information, see the web site of SNSN at Uppsala University.
Contact person:
Maxime Mouyen
Email: maxime.mouyen@chalmers.se, Phone: +46 31-772 5549
Tide gauges
see separate page
Time and frequency
Onsala Space Observatory hosts two hydrogen maser clocks and one cesium clock, and contributes to establishing the official Swedish time and international time. Radio astronomical observations, in particular VLBI observations, also depend on these very accurate clocks.
The observatory's time keeping activities are a cooperation with National Laboratory for Time and frequency at RISE Research Institutes of Sweden through our adjunct professor Jan Johansson.
Contact persons:
Jan Johansson
Email: jan.johansson@chalmers.se, Phone: +46 31-772 5558
Rüdiger Haas
Email: rudiger.haas@chalmers.se, Phone: +46 31-772 5530
- Head of Unit, Onsala Space Observatory, Space, Earth and Environment