GOCO: Gravity Observation Combination

The main objective of the GOCO initiative is to compute high-accuracy and high-resolution global gravity field models from complementary gravity data sources:

  • satellite gravity missions GOCE, GRACE and CHAMP, and SLR data (satellite-only models of the GOCO-S series)
  • plus terrestrial gravity field and satellite altimetry data (combined models GOCO-C)

The combination is done by superposition of full normal equations and applying optimized relative weighting strategies.

GOCO has been initiated in the frame of ESA's GOCE Data AO (project no. 4248), with the project partners responsible for the GOCE-only time-wise (TIM) models as the nucleus.

The GOCO consortium is composed of the following institutions, co-ordinated by the Institute of Astronomical and Physical Geodesy at Techinical University of Munich:

 More information can be found under goco.eu.

The combined satellite-only gravity field model GOCO06s

GOCO06s is a satellite-only, global gravity field model up to degree and order 300, with secular and annual variations up to degree and order 200. It was produced by the GOCO Team (Technical University of Munich, University of Bonn, Graz University of Technology, Austrian Academy of Sciences, University of Bern) and is based on 1,160,000,000 observations from 19 satellites. The contributing satellite mission are: GOCE (TIM6 gradiometer observations), GRACE (ITSG-Grace2018s), kinematic orbits from Swarm A+B+C, TerraSAR-X, TanDEM-X, CHAMP, GRACE and GOCE and SLR observations to LAGEOS, LAGEOS 2, Starlette, Stella, AJISAI, LARES, LARETS, Etalon 1/2 and BLITS. The combination of the individual data sources is performed by on the basis of the full systems of normal equations, where the relative weighting between each constituent is determined by variance component estimation. In order to account for the polar gap of GOCE, the solution is Kaula-regularized after degree and order 150.

When using the data please cite:

Kvas, A., Brockmann, J. M., Krauss, S., Schubert, T., Gruber, T., Meyer, U., Mayer-Gürr, T., Schuh, W.-D., Jäggi, A., Pail, R. (2021). GOCO06s - a satellite-only global gravity field model. Earth System Science Data, 13(1), 99–118. doi.org/10.5194/essd-13-99-2021

Kvas, Andreas; Mayer-Gürr, Torsten; Krauss, Sandro; Brockmann, Jan Martin; Schubert, Till; Schuh, Wolf-Dieter; Pail, Roland; Gruber, Thomas; Jäggi, Adrian; Meyer, Ulrich (2019): The satellite-only gravity field model GOCO06s. GFZ Data Services. http://doi.org/10.5880/ICGEM.2019.002

Available data sets:

  • The solution can be downloaded from ICGEM, goco.eu and the institutes' FTP server.
  • The full unconstrained system of normal equations and full covariance matrix of the solution can be downloaded from the institutes' FTP server.
  • Estimated co-seismic gravity changes for major earthquakes on the institutes' FTP server.

Formal accuracies of the GOCO satellite-only models.
Gravity anomalies of GOCO06s in the Pacific region (Blue Marble credit: NASA).

Torsten Mayer-Gürr
Steyrergasse 30/III
8010 Graz
Tel: +43 316 873-6359
Fax: +43 316 873-6845

Andreas Kvas
Steyrergasse 30/III
8010 Graz
Tel: +43/316/873-6347
Fax: +43/316/873-6845