Evaluation of the first GOCE static gravity field models using terrestrial gravity, vertical deflections and EGM2008 quasigeoid heights

Hirt, Christian; Gruber, Th.; Featherstone, Will

doi:10.1007/s00190-011-0482-y

Cited by 100 publications

(67 citation statements)

References 32 publications

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“…Over rugged terrain, EGM2008 omits significant short-wavelength (i.e., scales shorter ~5′) gravity signals originating from the gravitational attraction of the topography (e.g., Hirt 2010;Hirt et al 2010b;Hirt et al 2011). The EGM2008 surface functionals were therefore spectrally augmented using topography-implied gravity-effects from residual terrain model data (RTM, Forsberg 1984).…”

Section: Construction Of Euralpgm2011mentioning

confidence: 99%

Efficient and accurate high-degree spherical harmonic synthesis of gravity field functionals at the Earth’s surface using the gradient approach

Hirt

2012

J Geod

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Spherical harmonic synthesis (SHS) of gravity field functionals at the Earth's surface requires the use of heights. The present study investigates the gradient approach as an efficient yet accurate strategy to incorporate height information in SHS at densely-spaced multiple points. Taylor series expansions of commonly used functionals quasigeoid heights, gravity disturbances and vertical deflections are formulated, and expressions of their radial derivatives are presented to arbitrary order. Numerical tests show that first-order gradients, as introduced by Rapp (J Geod 71(5): 282-289, 1997) for degree-360 models, produce cm-to dm-level RMS approximation errors over rugged terrain when applied with EGM2008 to degree 2190. Instead, higher-order Taylor expansions are recommended that are capable of reducing approximation errors to insignificance for practical applications. Because the height information is separated from the actual synthesis, the gradient approach can be applied along with existing highly-efficient SHS routines to compute surface functionals at arbitrarily dense grid points. This confers considerable computational savings (above or well above one order of magnitude) over conventional point-by-point SHS. As an application example, an ultrahigh resolution model of surface gravity functionals (EurAlpGM2011) is constructed over the entire European Alps that incorporates height information in the SHS at 12,000,000 surface points. Based on EGM2008 and residual topography data, quasigeoid heights, gravity disturbances and vertical deflections are estimated at ~200 m resolution. As a conclusion, the gradient approach is efficient and accurate for high-degree SHS at multiple points at the Earth's surface.

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Section: Construction Of Euralpgm2011mentioning

confidence: 99%

Efficient and accurate high-degree spherical harmonic synthesis of gravity field functionals at the Earth’s surface using the gradient approach

Hirt

2012

J Geod

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“…Studies for the validation of GOCE-based gravity models through terrestrial data over various geographical regions have been carried out by Gruber et al (2011), Hirt et al (2011), Šprlák et al (2012, Voigt and Denker (2014), Rexer et al (2014). An evaluation of global gravity models over Greece can be found in Kotsakis and Katsambalos (2010), Vergos et al (2012), etc.…”

Section: Introductionmentioning

confidence: 99%

High-frequency analysis of Earth gravity field models based on terrestrial gravity and GPS/levelling data: a case study in Greece

Papanikolaou¹,

Papadopoulos²

2015

Journal of Geodetic Science

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The present study aims at the validation of global gravity field models through numerical investigation in gravity field functionals based on spherical harmonic synthesis of the geopotential models and the analysis of terrestrial data. We examine gravity models produced according to the latest approaches for gravity field recovery based on the principles of the Gravity field and steadystate Ocean Circulation Explorer (GOCE) and Gravity Recovery And Climate Experiment (GRACE) satellite missions. Furthermore, we evaluate the overall spectrum of the ultra-high degree combined gravity models EGM2008 and EIGEN-6C3stat. The terrestrial data consist of gravity and collocated GPS/levelling data in the overall Hellenic region. The software presented here implements the algorithm of spherical harmonic synthesis in a degree-wise cumulative sense. This approach may quantify the bandlimited performance of the individual models by monitoring the degree-wise computed functionals against the terrestrial data. The degree-wise analysis performed yields insight in the short-wavelengths of the Earth gravity field as these are expressed by the high degree harmonics.

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“…Hirt et al (2011) compared some of GOCE EGMs with terrestrial gravimetric data over Switzerland, Austria and astrogeodetic deflections over Europe. They observed some improvements between degrees 160-165 and 180-185.…”

Section: Introductionmentioning

confidence: 99%

Deterministically-Modified Integral Estimators of Gravitational Tensor

Romeshkani

Eshagh

2015

Bol. Ciênc. Geod.

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The Earth's global gravity field modelling is an important subject in Physical Geodesy. For this purpose different satellite gravimetry missions have been designed and launched. Satellite gravity gradiometry (SGG) is a technique to measure the second-order derivatives of the gravity field. The gravity field and steady state ocean circulation explorer (GOCE) is the first satellite mission which uses this technique and is dedicated to recover Earth's gravity models (EGMs) up to medium wavelengths. The existing terrestrial gravimetric data and EGM scan be used for validation of the GOCE data prior to their use. In this research, the tensor of gravitation in the local north-oriented frame is generated using deterministicallymodified integral estimators involving terrestrial data and EGMs. The paper presents that the SGG data is assessable with an accuracy of 1-2 mE in Fennoscandia using a modified integral estimatorby the Molodensky method. A degree of modification of 100 and an integration cap size of 2.5 o for integrating 55   terrestrial data are proper parameters for the estimator.

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Evaluation of the first GOCE static gravity field models using terrestrial gravity, vertical deflections and EGM2008 quasigeoid heights

Cited by 100 publications

References 32 publications

Efficient and accurate high-degree spherical harmonic synthesis of gravity field functionals at the Earth’s surface using the gradient approach

Efficient and accurate high-degree spherical harmonic synthesis of gravity field functionals at the Earth’s surface using the gradient approach

High-frequency analysis of Earth gravity field models based on terrestrial gravity and GPS/levelling data: a case study in Greece

Deterministically-Modified Integral Estimators of Gravitational Tensor

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