A combined regional Geopotential Model using optimized global Gravity Field Solutions

To develop a gravimetric geoid, a Global Geopotential Model (GGM) is required to minimise the truncation error arising from using the Stokes integral with a limited number of gravity data points. The choice of a best-fitting GGM determines the accuracy of a gravimetric geoid solution. Selecting a su...

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Published in:IOP Conference Series: Earth and Environmental Science
Main Author: Nyoka C.J.; Din A.H.M.; Pa'Suya M.F.; Omar A.H.
Format: Conference paper
Language:English
Published: Institute of Physics 2022
Online Access:https://www.scopus.com/inward/record.uri?eid=2-s2.0-85135486334&doi=10.1088%2f1755-1315%2f1051%2f1%2f012001&partnerID=40&md5=ae4fa428aba964425cd19588098de8e0
id 2-s2.0-85135486334
spelling 2-s2.0-85135486334
Nyoka C.J.; Din A.H.M.; Pa'Suya M.F.; Omar A.H.
A combined regional Geopotential Model using optimized global Gravity Field Solutions
2022
IOP Conference Series: Earth and Environmental Science
1051
1
10.1088/1755-1315/1051/1/012001
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85135486334&doi=10.1088%2f1755-1315%2f1051%2f1%2f012001&partnerID=40&md5=ae4fa428aba964425cd19588098de8e0
To develop a gravimetric geoid, a Global Geopotential Model (GGM) is required to minimise the truncation error arising from using the Stokes integral with a limited number of gravity data points. The choice of a best-fitting GGM determines the accuracy of a gravimetric geoid solution. Selecting a suitable GGM is a rigorous process, requiring both internal and external evaluation of all GGMs available at the International Center for Globa Earth Models (ICGEM). Moreover, GGMs perform differently depending on the wavelength, and it is difficult to obtain a GGM that performs best across the full harmonic spectrum. In this study, a combined GGM is developed from a selection of the most recent and high-resolution GGMs covering Peninsular Malaysia. The selected models are first synthesized harmonically to obtain geoid undulations at collocated GNSS-levelled points, and free air anomalies at randomly sampled points across the study area. These quantities are compared with the observed geoid undulations and point gravity anomalies interpolated from a grid of free air anomalies. The best performing GGMs are then used to produce a combined GGM, by selecting the spherical harmonic coefficients with the best characteristics for every degree. The signal and error spectra of the new GGM are compared with the selected geopotential models. The combined GGM produced a higher cumulative signal to noise ratio (SNR) of 4402.669 compared to all the selected GGMs, with XGM2016 and Eigen-6C following suit with SNR of 4139.561 and 4092.462, respectively. Besides, the new combined GGM performed better across the whole harmonic spectrum than all selected GGMs. The use of combined GGMs in geoid modelling, instead of a single GGM may be more desirable because they can improve the quality of results. © Published under licence by IOP Publishing Ltd.
Institute of Physics
17551307
English
Conference paper
All Open Access; Gold Open Access
author Nyoka C.J.; Din A.H.M.; Pa'Suya M.F.; Omar A.H.
spellingShingle Nyoka C.J.; Din A.H.M.; Pa'Suya M.F.; Omar A.H.
A combined regional Geopotential Model using optimized global Gravity Field Solutions
author_facet Nyoka C.J.; Din A.H.M.; Pa'Suya M.F.; Omar A.H.
author_sort Nyoka C.J.; Din A.H.M.; Pa'Suya M.F.; Omar A.H.
title A combined regional Geopotential Model using optimized global Gravity Field Solutions
title_short A combined regional Geopotential Model using optimized global Gravity Field Solutions
title_full A combined regional Geopotential Model using optimized global Gravity Field Solutions
title_fullStr A combined regional Geopotential Model using optimized global Gravity Field Solutions
title_full_unstemmed A combined regional Geopotential Model using optimized global Gravity Field Solutions
title_sort A combined regional Geopotential Model using optimized global Gravity Field Solutions
publishDate 2022
container_title IOP Conference Series: Earth and Environmental Science
container_volume 1051
container_issue 1
doi_str_mv 10.1088/1755-1315/1051/1/012001
url https://www.scopus.com/inward/record.uri?eid=2-s2.0-85135486334&doi=10.1088%2f1755-1315%2f1051%2f1%2f012001&partnerID=40&md5=ae4fa428aba964425cd19588098de8e0
description To develop a gravimetric geoid, a Global Geopotential Model (GGM) is required to minimise the truncation error arising from using the Stokes integral with a limited number of gravity data points. The choice of a best-fitting GGM determines the accuracy of a gravimetric geoid solution. Selecting a suitable GGM is a rigorous process, requiring both internal and external evaluation of all GGMs available at the International Center for Globa Earth Models (ICGEM). Moreover, GGMs perform differently depending on the wavelength, and it is difficult to obtain a GGM that performs best across the full harmonic spectrum. In this study, a combined GGM is developed from a selection of the most recent and high-resolution GGMs covering Peninsular Malaysia. The selected models are first synthesized harmonically to obtain geoid undulations at collocated GNSS-levelled points, and free air anomalies at randomly sampled points across the study area. These quantities are compared with the observed geoid undulations and point gravity anomalies interpolated from a grid of free air anomalies. The best performing GGMs are then used to produce a combined GGM, by selecting the spherical harmonic coefficients with the best characteristics for every degree. The signal and error spectra of the new GGM are compared with the selected geopotential models. The combined GGM produced a higher cumulative signal to noise ratio (SNR) of 4402.669 compared to all the selected GGMs, with XGM2016 and Eigen-6C following suit with SNR of 4139.561 and 4092.462, respectively. Besides, the new combined GGM performed better across the whole harmonic spectrum than all selected GGMs. The use of combined GGMs in geoid modelling, instead of a single GGM may be more desirable because they can improve the quality of results. © Published under licence by IOP Publishing Ltd.
publisher Institute of Physics
issn 17551307
language English
format Conference paper
accesstype All Open Access; Gold Open Access
record_format scopus
collection Scopus
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