The use of absolute gravity data for the validation of Global Geopotential Models and for improving quasigeoid heights determined from satellite-only Global Geopotential Models

Godah, Walyeldeen; Krynski, Jan; Szelachowska, Malgorzata

doi:10.1016/j.jappgeo.2018.03.002

Cited by 11 publications

(6 citation statements)

References 21 publications

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“…The EGM2008 model was found to be the best GGM available for India [23]. The second in situ data that serve for the validation of GGMs involve (ii) terrestrial gravimetric measurements [24]. In general, in most studies, GNSS/levelling and terrestrial gravimetric measurements have been used together, for example, for the validation of GOCE based GGMs in the southeast of Brazil [25], in Egypt [26], and in Japan [27]; and for the validation of GOCE/ GRACE derived GGMs in China [28] and in Greece [29].…”

Section: Evaluation Of Global Gravity Models From Absolute Gravity An...mentioning

confidence: 99%

“…Thus, a spectral inconsistency problem is induced between the two data sets which has to be considered before subtraction. To make both data sets comparable, the spectral enhancement method [31] 4) and ( 5), respectively [24]:…”

Section: Comparison Of Selected Ggms With Absolute Gravity Datamentioning

confidence: 99%

“…The assessment of the best-fitting GGM can be done by subtracting in situ VGG measurements from the GGM derived VGGs. The differences between terrestrial VGG (W terr zz ) and satellite-only GGM derived gravity gradients (W GGM zz sat.only ) and combined GGM derived gravity gradients (W GGM zz comb ) were determined as shown in equations ( 9)and ( 10), respectively and modified from [24]:…”

Section: Comparison Of Selected Ggms With Vggsmentioning

confidence: 99%

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Evaluation of global gravity models from absolute gravity and vertical gravity gradient measurements in Turkey

Akdoğan¹,

Yıldız²,

Ahi³

2019

Meas. Sci. Technol.

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A global gravity model (GGM) is a mathematical function describing the gravity field of the Earth. The assessment of GGMs involves identifying the best-fitting model to local gravity field for geodetic and geophysical applications. Thus, highly accurate independent datasets are required to obtain the appropriate model. In general, GPS/levelling data have been used for this purpose. If these measurements are not performed simultaneously, they may not be reliable due to vertical deformations especially in seismically active countries. Therefore, we used highly precise absolute and vertical gravity gradient measurements obtained by the Scientific and Technological Research Council of Turkey’s (TUBITAK) National Metrology Institute and General Directorate of Mapping within the frame of Turkish Height System Modernization and Gravity Recovery Project over the period of 2016–2018 from Turkey to choose the best GGM for the whole of Turkey among the 19 latest tested satellite-only and combined GGMs (2004–2018). Our results showed that vertical gravity gradient measurements could also be used for the regional validation of GGMs as an independent in situ dataset. The GOCE based XGM2016 combined model and GO_CONS_GCF_2_TIM_R5 satellite-based model were found to be the best-fitting models. The results also showed improvements over the widely used EGM2008 up to the spherical degree 270 for Turkey. The improvements of the GOCE models over the EGM2008 model are mostly seen in mountainous areas such as the Black sea, Aegean Sea, some parts of the Mediterranean, and South-eastern Anatolia regions with maximum improvements in the coastal areas of the Eastern Black Sea. The best-fitting GGMs to local gravity field identified with these measurements could be used for further geodetic and geophysical purposes in Turkey.

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Section: Evaluation Of Global Gravity Models From Absolute Gravity An...mentioning

confidence: 99%

Section: Comparison Of Selected Ggms With Absolute Gravity Datamentioning

confidence: 99%

Section: Comparison Of Selected Ggms With Vggsmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of global gravity models from absolute gravity and vertical gravity gradient measurements in Turkey

Akdoğan¹,

Yıldız²,

Ahi³

2019

Meas. Sci. Technol.

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“…The first map of the free-air gravity anomalies in Bouguer correction for the Pacific Ocean was created in the U.S. using both pendulum and marine gravity observations. Gravity measurements were then continuously performed using methods of the advanced data analysis (Drinkwater et al 2003;Knudsen et al 2011;Eshagh, 2013;Godah et al 2018).…”

Section: Introductionmentioning

confidence: 99%

GRASS GIS for topographic and geophysical mapping of the Peru-Chile Trench

Lemenkova¹

2020

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The study area is located along the western continental margins of South America, Peru-Chile Trench south-east Pacific Ocean, geographically encompasses 90° to 60°W longitude and 55°S to 0° latitude. The study aims to perform a spatial analysis using GRASS GIS approach applied for processing and visualizing topographic and geophysical data on the study area. Data include following raster grids: topographic SRTM_15PLUS raster grid with 15 arc-second resolution, geoid model (EGM96), geophysical fields and gravity maps (marine free-air gravity and vertically corrected free-air gravity). The thematic grids were mapped by GRASS GIS modules and visualized for comparative analysis. Spatial analysis included plotting slope aspect, profile curvature, terrain elevation and modeled topographic classes based on the neighborhood analysis. The results include visualized geophysical and topographic maps of the study area showing correlation between the geophysical fields and topographic elevation. The variety of forms of the submarine relief of the Pacific Ocean seafloor was formed as a result of complex factors: tectonic movements, dislocations, active volcanism, geologic variations in rock density, which is reflected in visualized gravity and geoid maps. The actuality of the study is explained by high potential commercial interests in deep-water mineral resource deposits, oil and gas, which make ocean seafloor studies one of the most promising topics in geoscience. At the same time, the need for programming applications for big data analysis in geosciences requires testing advanced scripting approaches in cartography. Therefore, the current paper presents a multi-disciplinary approach combining geological analysis with technical cartographic aspects of data analysis and visualization.

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“…In Godah and Krynski (2017), principal component analysis (PCA) method was used to decompose the periodic signal and then to compare the RL05 data to changes in normal and orthometric heights on the territory of Poland. The article Godah et al (2018) presents a comparison of satellite-only global geopotential models (GGMs) with quasigeoid undulation derived from levelling and Global Navigation Satellite Systems (GNSS) measurements. The article Godah et al (2015) presents a comparison of non-isotropic decorrelation filters (denoted by DDK) and Gauss filtration for the Vistula and Odra river basins based on data from the RL05 solution.…”

Section: Introductionmentioning

confidence: 99%

Accuracy Analysis of Gravity Field Changes from Grace RL06 and RL05 Data Compared to in Situ Gravimetric Measurements in the Context of Choosing Optimal Filtering Type

Szabó

Marjańska

2020

Artificial Satellites

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Global satellite gravity measurements provide unique information regarding gravity field distribution and its variability on the Earth. The main cause of gravity changes is the mass transportation within the Earth, appearing as, e.g. dynamic fluctuations in hydrology, glaciology, oceanology, meteorology and the lithosphere. This phenomenon has become more comprehensible thanks to the dedicated gravimetric missions such as Gravity Recovery and Climate Experiment (GRACE), Challenging Minisatellite Payload (CHAMP) and Gravity Field and Steady-State Ocean Circulation Explorer (GOCE). From among these missions, GRACE seems to be the most dominating source of gravity data, sharing a unique set of observations from over 15 years. The results of this experiment are often of interest to geodesists and geophysicists due to its high compatibility with the other methods of gravity measurements, especially absolute gravimetry. Direct validation of gravity field solutions is crucial as it can provide conclusions concerning forecasts of subsurface water changes. The aim of this work is to present the issue of selection of filtration parameters for monthly gravity field solutions in RL06 and RL05 releases and then to compare them to a time series of absolute gravimetric data conducted in quasi-monthly measurements in Astro-Geodetic Observatory in Józefosław (Poland). The other purpose of this study is to estimate the accuracy of GRACE temporal solutions in comparison with absolute terrestrial gravimetry data and making an attempt to indicate the significance of differences between solutions using various types of filtration (DDK, Gaussian) from selected research centres.

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The use of absolute gravity data for the validation of Global Geopotential Models and for improving quasigeoid heights determined from satellite-only Global Geopotential Models

Cited by 11 publications

References 21 publications

Evaluation of global gravity models from absolute gravity and vertical gravity gradient measurements in Turkey

Evaluation of global gravity models from absolute gravity and vertical gravity gradient measurements in Turkey

GRASS GIS for topographic and geophysical mapping of the Peru-Chile Trench

Accuracy Analysis of Gravity Field Changes from Grace RL06 and RL05 Data Compared to in Situ Gravimetric Measurements in the Context of Choosing Optimal Filtering Type

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