Static and Time-Variable Gravity from GRACE Mission Data

Schmidt, Roland; Flechtner, Frank; Meyer, Ulrich; Reigber, Christoph; Barthelmes, Franz; Förste, Christoph; Stubenvoll, R.; König, Rolf; Neumayer, Karl Hans; Zhu, S. Y.

doi:10.1007/3-540-29522-4_9

Cited by 10 publications

(12 citation statements)

References 15 publications

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“…Subsequent studies confirmed the quality of gravity field variation measurements with SGs in Europe (Crossley et al, 2005). With the increasing gravity and spatial resolution of GRACE solutions Schmidt et al, 2005), this kind of comparison is being studied in more detail with a worldwide selection of SG-stations (Neumeyer et al, 2006).…”

Section: Introductionmentioning

confidence: 86%

“…2.1 Improved monthly gravity field solutions from GRACE In this study, the recent time-series of monthly GRACEonly models provided by GFZ Potsdam is used (available at GFZ Information System and Data Centre (ISDC; http://isdc.gfz-potsdam. de/grace) General aspects of the gravity recovery from GRACE can be found in Reigber et al (2005), Schmidt et al (2005), and Neumeyer et al (2006). Here, we briefly highlight several major modifications that were made compared to the GFZ RL02 fields (see also Flechtner (2005) for full details on the processing of RL03 models):…”

Section: Preparing the Gravity Variations For Comparisonmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 86%

Section: Preparing the Gravity Variations For Comparisonmentioning

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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“…Tapley and Reigber 2001) satellite gravity mission is the recovery of temporal Earth gravity field variations. The results of a recent GRACE data evaluation show a gravity resolution in the µgal range at a half-wavelength (λ/2) spatial resolution of about 1,500 km for a temporal resolution of 1 month (Schmidt et al 2005a). Because of this remarkable gravity resolution, the comparison and validation of satellite-derived temporal gravity variations with ground gravity measurements is of fundamental interest.…”

Section: Introductionmentioning

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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“…Os coeficientes usados estão corrigidos dos efeitos de marés oceânica e terrestres, variações de massas em períodos curtos, e mudanças seculares nos coeficientes de grau 2, 3 e 4 devido ao processo de ajustamento isostático global via modelos a priori (SCHMIDT et al, 2006). Estes dados estão disponíveis no Information Systems and Data Center do GFZ (http://isdc.gfz-potsdam.de/grace) ou no International Centre for Global Earth Models (ICGEM, cf.…”

Section: Dados E Métodosunclassified

Análise de deformação por variação do geopotencial: estudo de caso para o terremoto maule (Mw 8,8) com base em dados mensais da missão Grace

Castro

Ferreira²,

Freitas

2012

Bol. Ciênc. Geod.

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RESUMOO Chile é um laboratório natural de estudos de Geodinâmica em vista da amplitude e variedade de eventos tectônicos. Um caso notável de deformação produzida é a decorrente do evento sísmico com magnitude 8,8w M = , denominado de terremoto do Maule. Este teve epicentro localizado a 60 km ao Sul de Constitución, região que já apresentava consideráveis velocidades obtidas por intermédio de medições GNSS. Vários estudos relacionados com o sinal geofísico gerado pelo terremoto foram realizados, principalmente explorados por intermédio deresultados GNSS e InSAR, somente um estudo com base em gravimetria. No entanto, tais estudos evidenciaram dificuldades relativas às séries temporais analisadas. Destaque-se que a maior parte das séries de posicionamento GNSS foram descontinuadas pelo evento e portanto só existem séries ou antes ou depois do evento. Neste estudo apresenta-se uma alternativa independente para a quantificação da deformação vertical da crosta com base nas variações do potencial anômalo fornecidas pelos coeficientes de

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Static and Time-Variable Gravity from GRACE Mission Data

Cited by 10 publications

References 15 publications

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

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

Análise de deformação por variação do geopotencial: estudo de caso para o terremoto maule (Mw 8,8) com base em dados mensais da missão Grace

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