Regional Gravity Field Modeling: Theory and Practical Results

Denker, Heiner

doi:10.1007/978-3-642-28000-9_5

Cited by 77 publications

(63 citation statements)

References 101 publications

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“…In this context, a note on the handling of the permanent (time-independent) parts of the tidal corrections is appropriate; for details, see, for example, Mäkinen and Ihde (2009), Ihde et al (2008), or Denker (2013. The IAG has recommended that the so-called zero-tide system should be used (resolutions no.…”

Section: Geodetic Methods For Determining the Gravity Potentialmentioning

confidence: 99%

“…(21)); hence, the latter term, contributing about 3 mm in terms of the height anomaly (corresponds to about 0.5 ppb; see Smith et al 2000;Ries 2014), has to be added in quadrature to the figures given above. Further details on the uncertainty estimates can be found in Denker (2013).…”

Section: The Gnss/geoid Approachmentioning

confidence: 99%

“…The major differences between EGG2015 and the previous EGG2008 model (Denker 2013) are the inclusion of additional gravity measurements carried out recently around all major European optical clock sites within the ITOC project (Margolis et al 2013;Margolis 2014; see also http://projects. npl.co.uk/itoc/) and the use of a newer geopotential model based on the GOCE satellite mission instead of EGM2008.…”

Section: The European Gravimetric Quasigeoid Model Egg2015mentioning

confidence: 99%

“…EGG2015 was computed from surface gravity data in combination with topographic information and the geopotential model GOCO05S (Mayer-Gürr et al 2015) based on the RCR technique, as outlined in "Appendix 2". The estimated uncertainty (standard deviation) of the absolute quasigeoid values is 1.9 cm; further details including correlation information can be found in "Appendix 2" as well as Denker (2013). In order to make EGG2015 consistent with GNSS and the EVRF2007, the final model values were computed according to Eq.…”

Section: The European Gravimetric Quasigeoid Model Egg2015mentioning

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: Geodetic Methods For Determining the Gravity Potentialmentioning

confidence: 99%

Section: The Gnss/geoid Approachmentioning

confidence: 99%

Section: The European Gravimetric Quasigeoid Model Egg2015mentioning

confidence: 99%

Section: The European Gravimetric Quasigeoid Model Egg2015mentioning

confidence: 99%

See 2 more Smart Citations

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

Self Cite

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“…The measurement was performed both by a levelling approach and by a Global Navigation Satellite System/geoid (GNSS/geoid) approach [46] ( ) = − [48,49]. Geometric levelling is accurate over short distances but is sus ceptible to systematic errors which may accumulate over dis tances >1000 km [50]. Therefore the GNSS/geoid approach is beneficial in the comparison between different laboratories by satellite or long haul optical fiber links.…”

Section: Gravitational Redshiftmentioning

confidence: 99%

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb

et al. 2017

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We report the absolute frequency measurement of the unperturbed transition S 1 0 -P 3 0 at 578 nm in 171 Yb realized in an optical lattice frequency standard relative to a cryogenic caesium fountain. The measurement result is 518 295 836 590 863.59(31) Hz with a relative standard uncertainty of 5.9 10 16 × − . This value is in agreement with the ytterbium frequency recommended as a secondary representation of the second in the International System of Units.

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A comparative assessment of coastal mean dynamic topography in Norway by geodetic and ocean approaches

2015

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The ocean's mean dynamic topography (MDT) is the surface representation of ocean circulation. It may be determined by the ocean approach, using numerical ocean circulation models, or by the geodetic approach, where MDT is the height of the mean sea surface (MSS), or mean sea level (MSL), above the geoid. Using new geoid models, geodetic MDT profiles based on tide gauges, dedicated coastal altimetry products, and conventional altimetry are compared with six ocean MDT estimates independent of geodetic data. Emphasis is put on the determination of high‐resolution geoid models, combining ESA's fifth release (R5) of GOCE satellite‐only global gravity models (GGMs) with a regional geoid model for Norway by a filtering technique. Differences between MDT profiles along the Norwegian coast together with Taylor diagrams confirm that geodetic and ocean MDTs agree on the ∼3–7 cm level at the tide gauges, and on the ∼5–11 cm level at the altimetry sites. Some geodetic MDTs correlate more with the best‐performing ocean MDT than do other ocean MDTs, suggesting a convergence of the methods. While the GOCE R5 geoids are shown to be more accurate over land, they do not necessarily show the best agreement over the ocean. Pointwise monomission altimetry products give results comparable with the multimission DTU13MSS grid on the ∼5 cm level. However, dedicated coastal altimetry products generally do not offer an improvement over conventional altimetry along the Norwegian coast.

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Regional Gravity Field Modeling: Theory and Practical Results

Cited by 77 publications

References 101 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

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb

A comparative assessment of coastal mean dynamic topography in Norway by geodetic and ocean approaches

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Regional Gravity Field Modeling: Theory and Practical Results

Cited by 77 publications

References 101 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

Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of171Yb

A comparative assessment of coastal mean dynamic topography in Norway by geodetic and ocean approaches

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Absolute frequency measurement of the ${{}^{1}}{{\text{S}}_{0}}$ – ${{}^{3}}{{\text{P}}_{0}}$ transition of¹⁷¹Yb