EGM_TIM_RL05: An independent geoid with centimeter accuracy purely based on the GOCE mission

Brockmann, Jan Martin; Zehentner, Norbert; Höck, Eduard; Pail, Roland; Loth, Ina; Mayer‐Gürr, Torsten; Schuh, Wolf-Dieter

doi:10.1002/2014gl061904

Cited by 147 publications

(72 citation statements)

References 45 publications

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“…Mayer-Gürr et al 2014), and 1.5 cm at about 110 km resolution (n = 185) from GOCE (e.g. Mayer-Gürr et al 2015;Brockmann et al 2014). However, the corresponding omission error at these wavelengths is still quite significant with values at the level of several decimetres, e.g.…”

Section: The Gnss/geoid Approachmentioning

confidence: 98%

“…Taking into account the given uncertainty estimates for the global geopotential model coefficients (including the uncertainty contribution of GM, see above) and the terrestrial data (assuming a standard deviation of 1 mGal with correlated noise), and supposing that a least-squares spectral combination of the satellite and terrestrial data is performed, results in a standard deviation of 3.1 cm for the combined (absolute) height anomalies based on the global model EGM2008, while the corresponding standard deviations based on the latest GRACE and GOCE (e.g. 5th generation; Brockmann et al 2014) global geopotential models are 2.5 cm and 1.9 cm, respectively. The major uncertainty contributions come from the spectral band 90 < n ≤ 360, while today the very long wavelengths (n ≤ 90) are accurately known from the GRACE mission, and the short wavelengths (n > 360) can be obtained from high-quality terrestrial data.…”

Section: Appendix 2: Regional Gravity Field Modellingmentioning

confidence: 99%

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Geodetic methods to determine the relativistic redshift at the level of 10 $$^{-18}$$ - 18 in the context of international timescales: a review and practical results

Denker

Timmen

Voigt

et al. 2017

J Geod

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The frequency stability and uncertainty of the latest generation of optical atomic clocks is now approaching the one part in 10 18 level. Comparisons between earthbound clocks at rest must account for the relativistic redshift of the clock frequencies, which is proportional to the corresponding gravity (gravitational plus centrifugal) potential difference. For contributions to international timescales, the relativistic redshift correction must be computed with respect to a conventional zero potential value in order to be consistent with the definition of Terrestrial Time. To benefit fully from the uncertainty of the optical clocks, the gravity potential must be determined with an accuracy of about 0.1 m 2 s −2 , equivalent to about 0.01 m in height. This contribution focuses on the static part of the gravity field, assuming that temporal variations are accounted for separately by appropriate reductions. Two geodetic approaches are investigated for the derivation of gravity potential values: geometric levelling and the Global Navigation Satellite Systems (GNSS)/geoid approach. Geometric levelling gives potential differences with millimetre uncertainty over shorter distances (several kilometres), but is susceptible to systematic errors at the decimetre level over large distances. The GNSS/geoid approach gives absolute gravity potential values, but with an uncertainty corresponding to about 2 cm in height. For large distances, the GNSS/geoid approach should therefore be better than geometric levelling. This is demonstrated by the results from practical investigations related to three clock sites in Germany and one in France. The estimated uncertainty for the relativistic redshift correction at each site is about 2 × 10 −18 .

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Section: The Gnss/geoid Approachmentioning

confidence: 98%

Section: Appendix 2: Regional Gravity Field Modellingmentioning

confidence: 99%

Geodetic methods to determine the relativistic redshift at the level of 10 $$^{-18}$$ - 18 in the context of international timescales: a review and practical results

Denker

Timmen

Voigt

et al. 2017

J Geod

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“…For this validation, the high- resolution EGM2008 model (Pavlis et al 2012) and the latest GOCE GGM based on the time-wise approach GOCE TIM R5 model (Brockmann et al 2014) are used. EGM2008 combines satellite-based gravity information of the GRACE satellite mission with terrestrial, airborne, and altimetric-derived gravity data that are partially supplemented with topography-implied gravity information.…”

Section: Validationmentioning

confidence: 99%

The Rock–Water–Ice Topographic Gravity Field Model RWI_TOPO_2015 and Its Comparison to a Conventional Rock-Equivalent Version

2016

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RWI_TOPO_2015 is a new high-resolution spherical harmonic representation of the Earth's topographic gravitational potential that is based on a refined Rock-Water-Ice (RWI) approach. This method is characterized by a three-layer decomposition of the Earth's topography with respect to its rock, water, and ice masses. To allow a rigorous separate modeling of these masses with variable density values, gravity forward modeling is performed in the space domain using tesseroid mass bodies arranged on an ellipsoidal reference surface. While the predecessor model RWI_TOPO_2012 was based on the 5 0 Â 5 0 global topographic database DTM2006.0 (Digital Topographic Model 2006.0), the new RWI model uses updated height information of the 1 0 Â 1 0 Earth2014 topography suite. Moreover, in the case of RWI_TOPO_2015, the representation in spherical harmonics is extended to degree and order 2190 (formerly 1800). Beside a presentation of the used formalism, the processing for RWI_TOPO_2015 is described in detail, and the characteristics of the resulting spherical harmonic coefficients are analyzed in the space and frequency domain. Furthermore, this paper focuses on a comparison of the RWI approach to the conventionally used rockequivalent method. For this purpose, a consistent rock-equivalent version REQ_TOPO_2015 is generated, in which the heights of water and ice masses are condensed to the constant rock density. When evaluated on the surface of the GRS80 ellipsoid (Geodetic Reference System 1980), the differences of RWI_TOPO_2015 and REQ_TOPO_2015 reach maximum amplitudes of about 1 m, 50 mGal, and 20 mE in terms of height anomaly, gravity disturbance, and the radial-radial gravity gradient, respectively. Although these differences are attenuated with increasing height above the ellipsoid, significant magnitudes can even be detected in the case of the satellite altitudes of current gravity field missions. In order to assess their performance, RWI_TOPO_2015, REQ_TOPO_2015, and RWI_TOPO_2012 are validated against independent gravity information of current global geopotential models, clearly demonstrating the attained improvements in the case of the new RWI model.

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“…For the purposes of our investigations we have chosen two satellite-based gravity field models go cons gcf 2 tim r5, jyy goce04s and the mixed model eigen-6c3stat which were created in 2014 using the results of gravity measurements from the GOCE mission (Brockmann et al, 2014;Förste et al, 2013).…”

Section: Modelsmentioning

confidence: 99%

Evaluation of recent Earth’s global gravity field models with terrestrial gravity data

Karpik

Kanushin

Ganagina

et al. 2016

Contributions to Geophysics and Geodesy

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Abstract:In the context of the rapid development of environmental research technologies and techniques to solve scientific and practical problems in different fields of knowledge including geosciences, the study of Earth's gravity field models is still important today. The results of gravity anomaly modelling calculated by the current geopotential models data were compared with the independent terrestrial gravity data for the two territories located in West Siberia and Kazakhstan. Statistical characteristics of comparison results for the models under study were obtained. The results of investigations show that about 70% of the differences between the gravity anomaly values calculated by recent global geopotential models and those observed at the points in flat areas are within ±10 mGal, in mountainous areas are within ±20 mGal.

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EGM_TIM_RL05: An independent geoid with centimeter accuracy purely based on the GOCE mission

Cited by 147 publications

References 45 publications

Geodetic methods to determine the relativistic redshift at the level of 10 $$^{-18}$$ - 18 in the context of international timescales: a review and practical results

Geodetic methods to determine the relativistic redshift at the level of 10 $$^{-18}$$ - 18 in the context of international timescales: a review and practical results

The Rock–Water–Ice Topographic Gravity Field Model RWI_TOPO_2015 and Its Comparison to a Conventional Rock-Equivalent Version

Evaluation of recent Earth’s global gravity field models with terrestrial gravity data

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