Data requirements for a 5-mm quasi-geoid in the Netherlands

Farahani, H. Hashemi; Klees, R.; Slobbe, Cornelis

doi:10.1007/s11200-016-0171-7

Cited by 20 publications

(7 citation statements)

References 42 publications

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“…For comparison purposes, the accuracy of gravimetry using modern relative gravimeters, such as Scintrex CG-6, is from 0,001 to 0,003• 10 -5 m s -2 . Required accuracy for geological exploration is around 0,01• 10 -5 m s -2 , for explorations of the oil, gas and minerals around 5• 10 -5 m s -2 (Seigel, 1995), for geoid determination from 1 to 5• 10 -5 m s -2 (Farahani et al, 2017). Solutions using DEMs with resolutions 5″, 10″ and 15″ for most of the areas have differences smaller than 1• 10 -5 m s -2 , which for only rare applications can be ignored.…”

Section: Discussionmentioning

confidence: 99%

Influence of digital elevation model resolution on gravimetric terrain correction over a study-area of Croatia

et al. 2019

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High-resolution digital elevation models (DEMs) have become available in the last decade. They are used in geodesy and geophysics as the main data for modeling of topographic mass effects included in gravimetric and gradiometric measurements. In modeling process, gravimeric terrain correction is the central quantity which accounts for the variations of topographic masses around measured stations. This study deals with one segment of terrain correction computation: the impact of the resolution of digital elevation models. Computations are performed on study area of Republic of Croatia. Newly created DEM/DBM for the study area is created from global digital surface model ASTER for continental area, and digital bathymetric model GEBCO for the sea area. DEMs with lower resolution were created by resampling of the created ASTER/GEBCO DEM/DBM in 1″ resolution. Terrain correction map is computed and published for the first time for the Republic of Croatia. The differences between terrain correction solutions obtained by using lower resolution DEMs compared to the solution obtained by using DEM with 1″ are indicating average influence of DEM resolution on terrain correction from 0,5·10–5 to 3·10–5 ms–2, for DEMs with lower resolution than 5″. The results also reveal that rugged and mountainous areas are particularly problematic in such computations.

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Section: Discussionmentioning

confidence: 99%

Influence of digital elevation model resolution on gravimetric terrain correction over a study-area of Croatia

et al. 2019

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“…This is a consequence of insufficient accuracy and density of the mean terrestrial gravity anomalies that were used in the computations. The role of the terrestrial gravity data accuracy for the quality of the calculated geoid model is explained by [83,84]. In accordance with a 1-2 mGal accuracy of the terrestrial gravity data, having 1-2 km spatial resolution with homogenous distribution is required if 1-2 cm accuracy of the geoid undulations is aimed.…”

Section: Testing the Ggms Contribution In Detailed Geoid Modelingmentioning

confidence: 99%

An Assessment of the GOCE High-Level Processing Facility (HPF) Released Global Geopotential Models with Regional Test Results in Turkey

2020

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The launch of dedicated satellite missions at the beginning of the 2000s led to significant improvement in the determination of Earth gravity field models. As a consequence of this progress, both the accuracies and the spatial resolutions of the global geopotential models increased. However, the spectral behaviors and the accuracies of the released models vary mainly depending on their computation strategies. These strategies are briefly explained in this article. Comprehensive quality assessment of the gravity field models by means of spectral and statistical analyses provides a comparison of the gravity field mapping accuracies of these models, as well as providing an understanding of their progress. The practical benefit of these assessments by means of choosing an optimal model with the highest accuracy and best resolution for a specific application is obvious for a broad range of geoscience applications, including geodesy and geophysics, that employ Earth gravity field parameters in their studies. From this perspective, this study aims to evaluate the GOCE High-Level Processing Facility geopotential models including recently published sixth releases using different validation methods recommended in the literature, and investigate their performances comparatively and in addition to some other models, such as GOCO05S, GOGRA04S and EGM2008. In addition to the validation statistics from various countries, the study specifically emphasizes the numerical test results in Turkey. It is concluded that the performance improves from the first generation RL01 models toward the final RL05 models, which were based on the entire mission data. This outcome was confirmed when the releases of different computation approaches were considered. The accuracies of the RL05 models were found to be similar to GOCO05S, GOGRA04S and even to RL06 versions but better than EGM2008, in their maximum expansion degrees. Regarding the results obtained from these tests using the GPS/leveling observations in Turkey, the contribution of the GOCE data to the models was significant, especially between the expansion degrees of 100 and 250. In the study, the tested geopotential models were also considered for detailed geoid modeling using the remove-compute-restore method. It was found that the best-fitting geopotential model with its optimal expansion degree (please see the definition of optimal degree in the article) improved the high-frequency regional geoid model accuracy by almost 15%.

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“…It was revealed that a minimum data spacing of 5 km without data gaps with a data noise between 0.1-0.5 mGal is suitable to achieve 5 mm geoid accuracy using the KTH method. Farahani et al (2017) assessed the surface gravity data requirements for a 5-mm quasi-geoid model considering the omission and commission errors. The study identified the relationship between omission error and data resolution as well as commission error and data accuracy.…”

Section: Introductionmentioning

confidence: 99%

Gravity data requirements for decimetre accuracy regional geoid using Stokes' Remove Compute Restore technique in Nigeria

Odumosu

Nnam

2020

Contrib. Geophys. Geod.

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The need for dense and accurate gravity data cannot be overemphasised in the development of a precise gravimetric geoid model. Unfortunately, the field observations required are costly, and labour-intensive hence the need to ascertain via numerical simulations the appropriate field specifications before embarking on them. This paper presents an experimental study on the gravimetric data specifications (spatial resolution and data accuracy) required for achieving decimetre-level accuracy geoid using the conventional Stokes' Remove Compute Restore (RCR) method in Nigeria. A two-step solution approach was used in this study. The steps were determination of the (i) effect of data spacing by a comparative assessment of computation results obtained by using gravity data at four user determined intervals and (ii) effect of observation accuracy by numerical simulation using error propagation analysis. The data intervals (3′×3′, 5′×5′, 10′×10′ and 20′×20′) were selected from a combination of 1815 terrestrial FA anomaly points merged with EGM2008 derived FA anomaly covering the study area. Also, observational errors investigated were 0 mGal, 0.1 mGal, 0.5 mGal, 1 mGal and 5 mGal. The study was conducted in Nigeria having a total land area of approximately 923,768 km2. The study established that gravimetric geoid accuracy improves substantially as the spatial resolution and accuracy of the gravity data improves. Also, the study identified that data spacing contributes more to the overall geoid error than data accuracy. In addition, the study observed that hilly regions should have denser data spacing than plain areas. Within the test region, a data spacing of 3′×3′ with gravity observational errors 5 mGal was found to produce an acceptable gravimetric geoid. The produced gravimetric geoid had a pre-fit Root Mean Square Error (RMSE) of 15.6 cm when compared with GNSS-Levelling data at 27 stations located evenly across the study area.

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Data requirements for a 5-mm quasi-geoid in the Netherlands

Abstract: We assess the surface gravity data requirements for a 5-mm quasi-geoid

Cited by 20 publications

References 42 publications

Influence of digital elevation model resolution on gravimetric terrain correction over a study-area of Croatia

Influence of digital elevation model resolution on gravimetric terrain correction over a study-area of Croatia

An Assessment of the GOCE High-Level Processing Facility (HPF) Released Global Geopotential Models with Regional Test Results in Turkey

Gravity data requirements for decimetre accuracy regional geoid using Stokes' Remove Compute Restore technique in Nigeria

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