Why is the Earth’s gravity field variable?
Various geodetic and geophysical research activities and applications rely on a precise monitoring of temporal variations of the Earth gravity field through long-term records from ground-based instruments. A global network of superconducting gravimeters plays a key role in providing high precision time series. The International Geodynamics and Earth Tides Service (IGETS) has been established as an IAG Service (within the IGFS – International Gravity Field Service) to provide the relevant information and data products to the geoscientific user community. It is collecting, archiving and distributing Earth tide records from long-term series from ground gravimeters, tiltmeters, strainmeters and other geodynamic sensors. IGETS has two analysis centers at the University of French Polynesia (Tahiti) and the University of Strasbourg (France). The main data center is hosted at GFZ Potsdam. The University of Strasbourg is also hosting the Central Bureau and a secondary data center. Further information is available at the IGETS overview page and official IGETS website.
The main data products of IGETS are divided into raw and processed records from worldwide superconducting gravimeters. In particular, data at different processing levels provided at IGETS data base are:
- Level-1: Raw gravity and local air pressure records sampled at 1 or 2 seconds, and/or resampled to 1-minute resolution;
- Level-2: Gravity and local air pressure records corrected for instrumental perturbations, ready for tidal analysis;
- Level-3: Gravity residuals after particular geophysical corrections, including solid Earth tides, polar motion, tidal and non-tidal loading effects.
Individual data DOI are issued for Level 1 datasets by the IGETS data center.
Additional IGETS Products
Apart from these main products, IGETS is also offering:
- Superconducting gravimeter data for major earthquakes (minute and second sampling) – IGETS data;
and is supporting supplemental products to process the main products (via links to other websites):
- Atmospheric attraction computation service Atmacs
- Toolbox mGlobe for computing hydrological, atmospheric and non-tidal ocean loading effects
- EOST loading service (displacements, gravity, tilts)