Gravity Observation Combination (GOCO)
Introduction
The main objective of the GOCO initiative is to compute high-accuracy and high-resolution global gravity field models from complementary gravity data sources:
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satellite gravity missions GOCE, GRACE and CHAMP, and SLR data (satellite-only models of the GOCO-S series)
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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 IAPG:
TU München, Institute of Astronomical and Physical Geodesy
Roland Pail (PI)
Thomas Gruber (Co-PI), Thomas Fecher, Moritz Rexer
University of Bonn, Institute of Geodesy and Geoinformation
Wolf-Dieter Schuh (Co-PI), Jürgen Kusche (Co-PI)
Jan-Martin Brockmann, Ina Krasbutter, Silvia Becker, Annette Eicker, Judith Schall
Graz University of Technology, Institute of Theoretical Geodesy and Satellite Geodesy
Torsten Mayer-Gürr (Co-PI)
Daniel Rieser, Norbert Zehentner
Austrian Academy of Sciences, Space Research Institute
Oliver Baur (Co-PI)
Eduard Höck, Walter Hausleitner, Andrea Maier, Sandro Krauss
University of Bern, Astronomical Institute
Adrian Jäggi (Co-PI)
Ulrich Meyer, Lars Prange
Model Download
| Model | Data | Reference |
|---|---|---|
| GOCO01S | GOCE, GRACE | Pail R., et al. (2010): Combined satellite gravity field model GOCO01S derived from GOCE and GRACE, Geophys. Res. Lett., 37, L20314,doi:10.1029/2010GL044906 |
| GOCO02S | GOCE, GRACE, CHAMP, SLR | Goiginger H., et al. (2011): The combined satellite-only global gravity field model GOCO02S. European Geosciences Union General Assembly 2011, Wien, 04.04.2011 PDF |
| GOCO03S | GOCE, GRACE, CHAMP, SLR | Mayer-Gürr T. et al. (2012): The new combined satellite only model GOCO03s. Abstract submitted to GGHS2012, Venice (Poster). |
| GOCO04S | A GOCO04S model was not processed. | |
| GOCO05S | GOCE, GRACE, Kinematic orbits (8 satellites), SLR (6 satellites) | Mayer-Gürr T., et al. (2015): The combined satellite gravity field model GOCO05s. Presentation at EGU 2015, Vienna, April 2015. |
| GOCO05C | GOCO05S plus terrestrial & altimetric gravity | Fecher, T.; Pail, R.; Gruber, Th.; GOCO, Consortium: GOCO05c: A New Combined Gravity Field Model Based on Full Normal Equations and Regionally Varying Weighting. Surveys in Geophysics 38 (3), 2017, 571–590 |
| GOCO06S | GOCE, GRACE, Kinematic orbits (9 satellites), SLR (10 satellites) | Kvas, A., et al (2019): The satellite-only gravity field model GOCO06s. GFZ Data Services. http://doi.org/10.5880/ICGEM.2019.002 |
Model description
Optimum combination based on the following data sets:
| Model | GOCO01S | GOCO02S | GOCO03S |
|---|---|---|---|
| (max. degree) | (224) | (250) | (250) |
| GOCE gradiometry | 2 months (Nov./Dec. 2009) | 8 months (Nov. 2009 – July 2010) | 18 months (Nov. 2009 – April 2011) |
| GRACE | ITG-Grace2010s (7.5 years) | ITG-Grace2010s (7.5 years) | ITG-Grace2010s (7.5 years) |
| Kinematic orbits | – | CHAMP, GOCE | CHAMP, GOCE |
| SLR | – | 5 years, 5 sat. | 5 years, 5 sat. |
| Constraints | Kaula, deg > 170 | Kaula, deg > 180 | Kaula, deg > 180 |
| Surface data | - | - | - |
| Model | GOCO05S | GOCO05C | GOCO06S |
|---|---|---|---|
| (max. degree) | (280) | (720) | (300) |
| GOCE gradiometry | Complete mission (Nov. 2009 – Oct. 2013) | Complete mission (Nov. 2009 – Oct. 2013) | Complete mission (Nov. 2009 – Oct. 2013) |
| GRACE | ITSG-Grace2014s (10.5 years) | ITSG-Grace2014s (10.5 years) | ITSG-Grace2018s (15.5 years) |
| Kinematic orbits | Swarm A+B+C, TerraSarX, Tandem-X, CHAMP, GRACE A+B, GOCE | Swarm A+B+C, TerraSarX, Tandem-X, CHAMP, GRACE A+B, GOCE | Swarm A+B+C, TerraSAR-X, Tandem-X, CHAMP, GRACE A+B, GOCE (TIM6 SST) |
| SLR | LAGEOS, LAGEOS 2, Starlette, Stella, Ajisai, Larets | LAGEOS, LAGEOS 2, Starlette, Stella, Ajisai, Larets | LAGEOS, LAGEOS 2, Starlette, Stella, Ajisai, LARES, Larets, Etalon 1/2, BLITS |
| Constraints | Kaula, deg > 150 | none | Kaula, deg > 150 |
| Surface data | - | DTU2013 altimetric gravity; Terrestrial/airborne gravity over Arctic, Australia, Canada, Europe, South America, USA | - |
For GOCE gradiometry the same processing strategy as for the time-wise (TIM) GOCE-only models (Pail et al., 2011) has been used.
The data periods of GOCE gradiometry contained in GOCO01S to GOCO03S and GOCO05S correspond to those of the pure GOCE models GOCE_TIM_R1 to GOCE_TIM_R3 and GOCE_TIM_R5.
In addition to static coefficients up to degree/order 280, GOCE05S contains also temporal variation parameters for trend and annual signals up to degree/order 100. The reference epoch is 2008-01-01 (MJD 54466).
Satellite Model Performance
Questions & Feedback
Your feedback is very important for us! Therefore, please send your questions, experience with the GOCO models and validation results to roland.pail(at)tum.de.
GOCO References & Material
Fecher T., Pail R., Gruber T. (2011):Global gravity field determination by combining GOCE and complementary data; in: Ouwehand, L. (eds.) Proceedings of the 4th International GOCE User Workshop, ESA Publication SP-696, ESA/ESTEC, ISBN (Online) 978-92-9092-260-5, ISSN 1609-042X, 2011; PDF.
Goiginger H., Rieser D., Mayer-Guerr T., Pail R., Schuh W.-D., Jäggi A., Maier A., GOCO Consortium (2011): The combined satellite-only global gravity field model GOCO02S. European Geosciences Union General Assembly 2011, Wien, 04.04.2011; PDF.
Maier A., Baur, O., Hausleitner W., Höck E., Krauss S., Goiginger H., Pail R., Jäggi A.; Schuh W.-D. (2011): Low-degree gravity field coefficients from SLR data for the new combined gravity field model GOCO02S. European Geosciences Union General Assembly 2011, Wien, 04.04.2011.
Mayer-Gürr T., Rieser D., Höck E., Brockmann J..M., Schuh W.-D., Krasbutter I., Kusche J., Maier A., Krauss S., Hausleitner W., Baur O., Jäggi A., Meyer U., Prange L., Pail R., Fecher T., Gruber T. (2012): The new combined satellite only model GOCO03s. Abstract submitted to GGHS2012, Venice (Poster).
Mayer-Gürr T., Pail R., Gruber T., Fecher T., Rexer M., Schuh W.-D., Kusche J., Brockmann J.-M., Rieser D., Zehentner N., Kvas A., Klinger B., Baur O., Höck E., Krauss S., Jäggi A. (2015): The combined satellite gravity field model GOCO05s. Presentation at EGU 2015, Vienna, April 2015.
Pail R., Bruinsma S., Migliaccio F., Förste C., Goiginger H., Schuh W.-D., Höck E., Reguzzoni M., Brockmann J.M., Abrikosov O., Veicherts M., Fecher T., Mayrhofer R., Krasbutter I., Sansò F., Tscherning C.C. (2011): First GOCE gravity field models derived by three different approaches; Journal of Geodesy, Vol. 85, Nr. 11, pp 819-843, Springer, ISSN 0949-7714, DOI: 10.1007/s00190-011-0467-x; Link.
Pail R., Goiginger H., Schuh W.D., Höck E., Brockmann J.M., Fecher T., Mayer-Gürr T., Kusche J., Jäggi A., Rieser D., Gruber T. (2011). Combination of GOCE data with complementary gravity field information (GOCO). Proceedings of 4th International GOCE User Workshop, München, 31.03.2011; PDF.
Pail R., Goiginger H., Schuh W.-D., Höck E., Brockmann J.M., Fecher T., Gruber T., Mayer-Gürr T., Kusche J., Jäggi A., Rieser D. (2010): Combined satellite gravity field model GOCO01S derived from GOCE and GRACE. Geophysical Research Letters, Vol. 37, EID L20314, American Geophysical Union, ISSN 0094-8276, DOI: 10.1029/2010GL044906; Link.
Fecher, T.; Pail, R.; Gruber, Th.; GOCO, Consortium: GOCO05c: A New Combined Gravity Field Model Based on Full Normal Equations and Regionally Varying Weighting. Surveys in Geophysics 38 (3), 2017, 571–590 doi: 10.1007/s10712-016-9406-y Link
Brockmann, J.M.; Zehentner, N.; Höck, E.; Pail, R.; Loth, I.; Mayer-Gürr, T.; Schuh, W.D.: EGM TIM RL05: An Independent Geoid with Centimeter Accuracy Purely Based on the GOCE Mission. Geophysical Research Letters, doi: 10.1002/2014GL061904, 2014 Link
Fecher, T.; Pail, R.; Gruber, T.: Global gravity field modeling based on GOCE and complementary gravity data. International Journal of Applied Earth Observation and Geoinformation, doi: 10.1016/j.jag.2013.10.005 2013 Link