The new ESA satellite‐only gravity field model via the direct approach

Bruinsma, Sean; Förste, Christoph; Abrikosov, O. A.; Marty, J.; Rio, Marie Hélène; Mulet, Sandrine; Bonvalot, Sylvain

doi:10.1002/grl.50716

Cited by 163 publications

(75 citation statements)

References 20 publications

(21 reference statements)

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“…However, due to the lack of an accurate geoid, the computation of the MDT at short scales with sufficient accuracy is not trivial. The recent release of geoid models based on the use of GOCE data (Gravity field and Ocean Circulation Explorer; Pail et al, 2011) or a combination of GOCE and GRACE (Gravity Recovery and Climate Experiment) data (Bruinsma et al, 2013) has led to significant improvements for the calculation of the ocean MDT at scales down to 125 km (Mulet et al, 2012). However, in the Mediterranean Sea, where the Rossby radius is of the order of 10 km, and the basin geometry characterized by narrow straits and numerous islands, this resolution is not sufficient to capture the small details and sharp coastal gradients of the circulation.…”

Section: Introductionmentioning

confidence: 99%

Computation of a new mean dynamic topography for the Mediterranean Sea from model outputs, altimeter measurements and oceanographic in situ data

et al. 2014

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Abstract. The accurate knowledge of the ocean's mean dynamic topography (MDT) is a crucial issue for a number of oceanographic applications and, in some areas of the Mediterranean Sea, important limitations have been found pointing to the need of an upgrade. We present a new MDT that was computed for the Mediterranean Sea. It profits from improvements made possible by the use of extended data sets and refined processing. The updated data set spans the 1993-2012 period and consists of drifter velocities, altimetry data, hydrological profiles and model data. The methodology is similar to the previous MDT by Rio et al. (2007). However, in Rio et al. (2007) no hydrological profiles had been taken into account. This required the development of dedicated processing. A number of sensitivity studies have been carried out to obtain the most accurate MDT as possible. The main results from these sensitivity studies are the following: moderate impact to the choice of correlation scales but almost negligible sensitivity to the choice of the first guess (model solution). A systematic external validation to independent data has been made to evaluate the performance of the new MDT. Compared to previous versions, SMDT-MED-2014 (Synthetic Mean Dynamic Topography of the MEDiterranean sea) features shorter-scale structures, which results in an altimeter velocity variance closer to the observed velocity variance and, at the same time, gives better Taylor skills.

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Section: Introductionmentioning

confidence: 99%

Computation of a new mean dynamic topography for the Mediterranean Sea from model outputs, altimeter measurements and oceanographic in situ data

et al. 2014

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“…[11]), combined satellite GGMs (e.g., Ref. [12]), and high-resolution GGMs (e.g., Ref. [13]), which are a combination of satellite and ground-based data.…”

Section: Global Geopotential Models (Ggms) and Errorsmentioning

confidence: 99%

“…We use the Earth Gravitational Model 2008, EGM2008 [13], and the fifth releases of the direct, DIR-R5 [12], and time-wise, TIM-R5 [11] solutions of the Gravity field and steady-state Ocean Circulation Explorer (GOCE); and GOCE and EGM2008 Combined Model, GECO [15]. These are available online at http://icgem.gfz-potsdam.de/home.…”

Section: Global Geopotential Models (Ggms) and Errorsmentioning

confidence: 99%

Towards the Selection of an Optimal Global Geopotential Model for the Computation of the Long-Wavelength Contribution: A Case Study of Ghana

2017

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Abstract:The selection of a global geopotential model (GGM) for modeling the long-wavelength for geoid computation is imperative not only because of the plethora of GGMs available but more importantly because it influences the accuracy of a geoid model. In this study, we propose using the Gaussian averaging function for selecting an optimal GGM and degree and order (d/o) for the remove-compute-restore technique as a replacement for the direct comparison of terrestrial gravity anomalies and GGM anomalies, because ground data and GGM have different frequencies. Overall, EGM2008 performed better than all the tested GGMs and at an optimal d/o of 222. We verified the results by computing geoid models using Heck and Grüninger's modification and validated them against GPS/trigonometric data. The results of the validation were consistent with those of the averaging process with EGM2008 giving the smallest standard deviation of 0.457 m at d/o 222, resulting in an 8% improvement over the previous geoid model. In addition, this geoid model, the Ghanaian Gravimetric Geoid 2017 (GGG 2017) may be used to replace second-order class II leveling, with an expected error of 6.8 mm/km for baselines ranging from 20 to 225 km.

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“…The TIM-R4 GGM is distinguished as a GOCE-only model in a rigorous sense, i.e. no external gravity fi eld information is used, neither as a reference model, nor for constraining the solution (Pail et al, 2011), while the DIR-R4 GGM is a satellite-only model based on a combination of GOCE data together with GRACE and LAGEOS data (Bruinsma et al, 2013). Both models have shown high performance worldwide (Yi and Rummel, 2014).…”

Section: Goce-based Global Geopotential Models (Ggms)mentioning

confidence: 99%

Accuracy assessment of GOCE-based geopotential models and their use for modelling the gravimetric quasigeoid - A case study for Poland

Godah¹,

Szelachowska²,

Krynski³

2014

Geodesy and Cartography

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Abstract:The GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) has signifi cantly upgraded the knowledge on the Earth gravity fi eld. In this contribution the accuracy of height anomalies determined from Global Geopotential Models (GGMs) based on approximately 27 months GOCE satellite gravity gradiometry (SGG) data have been assessed over Poland using three sets of precise GNSS/levelling data. The fi ts of height anomalies obtained from 4 th release GOCE-based GGMs to GNSS/levelling data were discussed and compared with the respective ones of 3 rd release GOCE-based GGMs and the EGM08. Furthermore, two highly accurate gravimetric quasigeoid models were developed over the area of Poland using high resolution Faye gravity anomalies. In the fi rst, the GOCE-based GGM was used as a reference geopotential model, and in the second -the EGM08. They were evaluated with GNSS/levelling data and their accuracy performance was assessed. The use of GOCE-based GGMs for recovering the long-wavelength gravity signal in gravimetric quasigeoid modelling was discussed.

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The new ESA satellite‐only gravity field model via the direct approach

Cited by 163 publications

References 20 publications

Computation of a new mean dynamic topography for the Mediterranean Sea from model outputs, altimeter measurements and oceanographic in situ data

Computation of a new mean dynamic topography for the Mediterranean Sea from model outputs, altimeter measurements and oceanographic in situ data

Towards the Selection of an Optimal Global Geopotential Model for the Computation of the Long-Wavelength Contribution: A Case Study of Ghana

Accuracy assessment of GOCE-based geopotential models and their use for modelling the gravimetric quasigeoid - A case study for Poland

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