Gravity reduction with three-dimensional atmospheric pressure data for precise ground gravity measurements

Neumeyer, J.; Hagedoorn, Jan; Leitloff, Jens; Schmidt, T.

doi:10.1016/j.jog.2004.07.006

Cited by 57 publications

(51 citation statements)

References 5 publications

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“…The effects of atmospheric variations are reduced using data from ECMWF. The attraction effect is removed by a 3D-modelling up to a spherical distance of 5° (Neumeyer et al, 2004(Neumeyer et al, , 2006aAbe et al, 2009;Klügel and Wziontek, 2009). For the remaining parts of the Earth's surface the reduction is based on surface pressure (Merriam, 1992), which is used as well for the reduction of the atmospheric loading.…”

Section: Reductions For the Consistent Combination Of Gravity Time Sementioning

confidence: 99%

Gravity field variations from superconducting gravimeters for GRACE validation

Weise

Kröner

Abe

et al. 2009

Journal of Geodynamics

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The network of superconducting gravimeters (SG) of the 'Global Geodynamics Project' (GGP) offers the unique opportunity to supplement and validate the gravity field variations derived from the GRACE satellite mission. Because of the different spatial and temporal resolution of the gravity data a combination of all data sets can be used to retrieve a maximum of information regarding mass transfers especially related to hydrology which is deployable as constraint for hydrological modelling.For a consistent combination of the data sets the gap between terrestrial data of superconducting and absolute gravimeters (AG) and from satellite data has to be bridged.A successful combination of SG and AG data could be realized for several stations which resulted in time series of highest accuracy and long-term stability.In principle, the same reductions applied to GRACE data have to be taken into account for the terrestrial data. The separation of local hydrological effects in SG observations is crucial for the comparison with satellite-derived gravity data. It is shown that even for stations with a hydrological challenging situation such as Moxa/Germany local hydrology-induced effects can be successfully modelled.* corresponding author, phone: +49-3641-948609, fax: +49-3641-948662, email:Adelheid.Weise@uni-jena.dePage 2 of 21A c c e p t e d M a n u s c r i p tCurrently, the study focuses on Europe with its dense and long-term observation network. Regarding the consistency of the SG gravity variations they are representative for a larger region. From a comparison with GRACE-derived gravity field changes, and the variations due to hydrological models a principle good agreement emerges.

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Section: Reductions For the Consistent Combination Of Gravity Time Sementioning

confidence: 99%

Gravity field variations from superconducting gravimeters for GRACE validation

Weise

Kröner

Abe

et al. 2009

Journal of Geodynamics

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“…This gravity effect consists of both an attraction and deformation part. The calculation of the attraction term is performed with the program 3DAP (Neumeyer et al, 2004b), while the deformation term is calculated according to the Green's function for atmospheric loading (Merriam, 1992;Sun, 1995).…”

Section: Sg Gravity Variationsmentioning

confidence: 99%

Analysis of gravity field variations derived from Superconducting Gravimeter recordings, the GRACE satellite and hydrological models at selected European sites

et al. 2008

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If we restrict the spatial resolution to a half-wavelength of about 1500 km and the temporal resolution to 1 month, GRACE-derived temporal gravity variations can be resolved within the μgal (10 −8 m/s 2 ) range. A comparison with ground gravity measurements from selected Superconducting Gravimeter (SG) stations forming the Global Geodynamics Project (GGP) provides an independent validation. For this study, five European SGstations were selected that both cover a large test field and allow closely located SG-stations to be studied. Prior to this comparison, GRACE and SG data sets have to be reduced for the same known gravity effects due to Earth and ocean tides, pole tide, and atmosphere. After these reductions, the remaining part can be mainly attributed to mass changes in terrestrial water storage. For this reason, gravity variations derived from global hydrological models are included in the comparison of SG and GRACE results. Conversely, the hydrology models can be checked by gravity variations determined from GRACE and SG observations. For most of the SG locations investigated here, the comparison based primarily on computed correlations shows quite a good agreement among the gravity variation derived from the three different kinds of data sets: SG, GRACE, and hydrology models. The variations in SG gravity (point measurements) prove to be representative for a large area within the μgal accuracy range, if local gravity effects are removed correctly. Additionally, a methodology for an analysis of dominant common features based on the EOF-technique is proposed and illustrated. The first principal component shows strong periodicity, and the search for arbitrary periods confirms a strong common annual component, which reduces the total signal content considerably. The first eigenvector reveals common features and differences between distinct SG stations. Discrepancies between SG, GRACE, and hydrology models at individual SG stations, detected by both methods, may provide valuable hints for further investigations of respective data series.

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“…This gravity effect consists of both attraction and deformation part. The calculation of the attraction term is performed with the program 3DAP (Neumeyer et al 2004b), which considers the real air density redistribution in the atmosphere. This result is more precise than the calculation with local or 2D atmospheric pressure data, because the surface pressure independent (SPI) part of the attraction term can only be determined with 3D data.…”

Section: Sg Gravity Variationsmentioning

confidence: 99%

Combination of temporal gravity variations resulting from superconducting gravimeter (SG) recordings, GRACE satellite observations and global hydrology models

et al. 2006

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Gravity recovery and climate experiment (GRACE)-derived temporal gravity variations can be resolved within the µgal (10 −8 m/s 2 ) range, if we restrict the spatial resolution to a half-wavelength of about 1,500 km and the temporal resolution to 1 month. For independent validations, a comparison with ground gravity measurements is of fundamental interest. For this purpose, data from selected superconducting gravimeter (SG) stations forming the Global Geodynamics Project (GGP) network are used. For comparison, GRACE and SG data sets are reduced for the same known gravity effects due to Earth and ocean tides, pole tide and atmosphere. In contrast to GRACE, the SG also measures gravity changes due to load-induced height variations, whereas the satellite-derived models do not contain this effect. For a solid spherical harmonic decomposition of the gravity field, this load effect can be modelled using degreedependent load Love numbers, and this effect is added to the P. Schwintzer has deceased. satellite-derived models. After reduction of the known gravity effects from both data sets, the remaining part can mainly be assumed to represent mass changes in terrestrial water storage. Therefore, gravity variations derived from global hydrological models are applied to verify the SG and GRACE results. Conversely, the hydrology models can be checked by gravity variations determined from GRACE and SG observations. Such a comparison shows quite a good agreement between gravity variation derived from SG, GRACE and hydrology models, which lie within their estimated error limits for most of the studied SG locations. It is shown that the SG gravity variations (point measurements) are representative for a large area within the µgal accuracy, if local gravity effects are removed. The individual discrepancies between SG, GRACE and hydrology models may give hints for further investigations of each data series.

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Gravity reduction with three-dimensional atmospheric pressure data for precise ground gravity measurements

Cited by 57 publications

References 5 publications

Gravity field variations from superconducting gravimeters for GRACE validation

Gravity field variations from superconducting gravimeters for GRACE validation

Analysis of gravity field variations derived from Superconducting Gravimeter recordings, the GRACE satellite and hydrological models at selected European sites

Combination of temporal gravity variations resulting from superconducting gravimeter (SG) recordings, GRACE satellite observations and global hydrology models

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