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Rational formulation of modern geoid concept

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中国有色金属学会会刊：英文版 2011年第S3期21卷 675-680页

作者： GUO Zeng-zhang, XIAO Jian-hua Geodesy Institute, Henan Polytechnic University, Jiaozuo 454000, China Geodesy Institute Henan Polytechnic University Jiaozuo 454000 China

Based on modern geometrical field theory, a rational interpretation of modern geodesic surface concept was formulated. The general equations for geodesic surface were given. The height concept and arc length concept were formulated strictly. Their intrinsic benefits and shortages of parameter-center reference and mass-center reference systems were studied in details. The research results show that the geodesic concept depends on the available technology. The technology-dependence feature of geodesy concept was expressed by related mathematic formulations. For the satellite-based observation system, the rationality of China-2000 geoid Reference System was explained. Discussions about how to establish regional precision reference system were made based on general equations of arc length and space distance equations. A new correction item should be taken into consideration for arc length gauge calculation.

关键词： geodesic surface parameter-center system mass-center system geodesy deformation geoid

Application of geoid Anomalies to the Tectonic Research in the East Asian Continental Margin

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Journal of Ocean University of China 2018年第4期17卷 811-822页

作者： WU Xiaoyang XING Junhui LI Chaoyang LIU Xinzhe YANG Kai CHEN Hongyan GONG Wei College of Marine Geosciences Ocean University of China Key Laboratory of Submarine Geosciences and Prospecting Techniques Ministry of Education Evaluation and Detection Technology Laboratory of Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology

In this paper, we calculated multi-scale residual geoid anomalies with the method of geoid separation processing, according to EGM2008 ultra-high order gravity field model, remove-restore technique and Stokes integral. The East Asian continental margin was selected as the study area. The residual geoid anomalies have been calculated by programming. On the basis of residual geoid anomalies at various orders, the interlayer geoid anomalies at different depths were calculated to depict the spatial distribution characteristics of the residual geoid. Finally, we conducted a detailed geophysical interpretation for the study area according to the geoid anomalies in combination with other geophysical datasets. Four conclusions can be outlined as follows: 1) it is impracticable that geoid anomalies are used in the interpretation of the shallow objects due to the influence of the terrain; 2) the anomalies of residual geoid can reflect the intensity of small-scale mantle convection in the asthenosphere; 3) the interlayer geoid anomalies can reflect the magmatic activities associated with the mantle convection and mantle plume in different scales; 4) the study of the geoid may provide an approach for the research of the subduction zone, mantle convection and mantle plume.

关键词： EGM2008 gravity field model geoid anomalies the East Asian continental margin structural interpretations

The effect of topographic density variations on the geoid and orthometric heights in Hong Kong

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Geodesy and Geodynamics 2024年第5期15卷 495-503页

作者： Albertini Nsiah Ababio Department of Land Surveying and Geo-Informatics Hong Kong Polytechnic UniversityHong KongChina

Utilizing the adopted average topographic density of 2670 kg/m^(3)in the reduction of gravity anomalies introduces errors attributed to topographic density variations,which consequently affect geoid modeling ***,the mean gravity along the plumbline within the topography in the definition of Helmert orthometric heights is computed approximately by applying the Poincar e-Prey gravity reduction where the topographic density variations are *** Helmert orthometric heights of benchmarks are then affected by *** errors could be random or systematic depending on the specific geological setting of the region where the leveling network is physically established and/or the geoid model is *** example of systematic errors in orthometric heights can be given for large regions characterized by sediment or volcanic deposits,the density of which is substantially lower than the adopted topographic density used in Helmert's definition of *** same applies to geoid modeling *** this study,we investigate these errors in the Hong Kong territory,where topographic density is about 20%lower than the density of 2670 kg/m^(3).We use the digital rock density model to estimate the effect of topographic density variations on the geoid and orthometric *** results show that this effect on the geoid and Helmert orthometric heights reach maxima of about 2.1 and 0.5 cm,*** results provide clear evidence that rock density models are essential in physical geodesy applications involving gravimetric geoid modeling and orthometric height determination despite some criticism that could be raised regarding the reliability of these density ***,in regions dominated by sedimentary and igneous rocks,the geological information is essential in these applications because topographic densities are substantially lower than the average density of 2670 kg/m^(3),thus introducing large systematic errors in geoid and orthometric

关键词： Rock density geoid Topography Heights Leveling network

Determination of geoid and elevation of the Mt. Qomolangma and discussion on the role of vertical gravity gradient

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Chinese Science Bulletin 1997年第20期42卷 1723-1725页

作者： ZHANG ChijunInstitute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan China

IT is known that the Mt. Qomolangma is the highest peak in the world. It was recorded in the'Map of Complete Territory of the Qin Dynasty' (published in 1717). As the highest peak,the Mt. Qomolangma not only provokes the interest of climbers but also arouses much atten-tion of geodesists. A significant cause is that the Mt. Qomolangma is located in the collisionbelt between the Indian Plate and the Eurasian Plate. According to the relative

关键词： geoid orthometric height the Mt. Qomolangma.

Influencing factors on the accuracy of local geoid model

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Geodesy and Geodynamics 2019年第6期10卷 439-445页

作者： Shazad Jamal Jalal Tajul Ariffin Musa Ami Hassan Md Din Wan Anom Wan Aris WenBin Shen Muhammad Faiz Pa’suya Faculty of Built Environment and Surveying Universiti Teknologi Malaysia(UTM)Johor Bahru81310Malaysia College of Engineering University of Sulaimanii46001SulaimaniIraq School of Geodesy and Geomatics Wuhan UniversityWuhan430079China Centre of Studies for Surveying Science&Geomatics Faculty of Architecture Planning&SurveyingUniversiti Teknologi MARAPerlis Branch Arau Campus02600ArauPerlisMalaysia

Different modification methods and software programs were developed to obtain accurate local geoid models in the past two *** quantitative effect of the main factors on the accuracy of local geoid modeling is still ambiguous and has not been clearly diagnosed *** study presents efforts to find the most influential factors on the accuracy of the local geoid model,as well as the amount of each factor’s effect *** methodology covers extracting the quantitative characteristics of 16 articles regarding local geoid models of different *** Statistical Package of Social Sciences(SPSS)software formulated a strong multiple regression model of correlation coefficient r = 0.999 with a high significance coefficient of determination R^2 = 0.997 and adjusted R^2 = 0,98 for the required effective ***,factor analysis is utilized to extract the dominant factors which include:accuracy of gravity data(40%),the density of gravity data(25%)(total gravity factors is 65%),the Digital Elevation Model(DEM)resolution(16%),the accuracy of GPS/leveling points(10%)and the area of the terrain of the country/state under the study(9%).These results of this study will assist in developing more accurate local geoid models.

关键词： Accuracy of local geoid model Multiple regression model Influence factors

Using satellite altimetry leveling to assess the marine geoid

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Geodesy and Geodynamics 2020年第2期11卷 106-111页

作者： Zhengtao Wang Nengfang Chao Dingbo Chao School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China College of Marine Science and Technology China University of GeosciencesWuhan 430074China

Based on the concept of Global Position System(GPS)/leveling,the satellite altimetry leveling(SAL) is first proposed to evaluate the marine *** is derived by the difference among the mean sea surface(MSS),mean dynamic ocean topography(MDT),and leveling *** this study,(1) the original satellite altimetry data are processed to infer the vertical deflection and gravity anomaly,(2) the Chinese coastal marine geoids(CMG) are determined by using the differe nt methods(including Molodensky,least square collocation,Stokes formula,and two-dimensional fast Fourier transformation(FFT) with the vertical deflection and gravity anomaly data),(3) CMG are evaluated by using the results from above different methods,the Gravity field and steady-state Ocean Circulation Explorer(GOCE) gravity potential model(GGPM),and *** results show that(1) CMG from the Molodensky method has the highest precision by using vertical de flection data,(2) the accuracy of CMG indicate good consistency between the SAL and GGPM,(3) SAL can be used as a new method for assessing marine geoid.

关键词： Satellite altimetry leveling Marine geoid Vertical deflection Gravity anomaly

Precise geoid computation using Stokes-Helmert’s scheme and strict integrals of topographic effects

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Geodesy and Geodynamics 2019年第4期10卷 290-296页

作者： Dongmei Guo Huiyou He Peng Sang State Key Laboratory of Geodesy and Earth’s Dynamics Institute of Geodesy and Geophysics The Chinese Academy of Science

The high-precision local geoid model was computed based on the improved Stokes-Helmert0 s boundary value problem and strict integrals of topographic effects. This proposed method involves three ***, the mathematical form of Stokes-Helmert0 s boundary value problem was derived, and strict computational formulas regarding topographic effects were provided to overcome the disadvantage of planar approximations. Second, a gravimetric geoid model was constructed using the proposed StokesHelmert0 s scheme with a heterogeneous data set. Third, a least squares adjustment method combined with a multi-surface function model was employed to remove the bias between the gravimetric geoid model and the GNSS/leveling data and to refine the final local geoid model. The accuracy of the final geoid model was evaluated using independent GNSS/leveling data. Numerical results show that an external precision of 1.45 cm is achievable.

关键词： geoid computation Stokes-Helmert’s method Surface integration Heterogeneous heights

A Local geoid Determination Based on Ellipsoid Approximation in Western China

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Geo-Spatial Information Science 2002年第3期5卷 6-10页

作者： Essam Ghanem Banha Higher Institute of Technology (BHIT) Banha Egypt

A new methodology for precise geoid determination with finest local details based on ellipsoidal approximation is *** methodology is formulated through the "fixed_free two_boundary value problem" based on the observable of the type modulus of gravity intensity,gravity acceleration and gravity potential at the GPS positioned stations,with support of the known geoid’s potential value,W

关键词： ellipsoid approximation geoid determination GPS

Determination of Istanbul geoid using GNSS/levelling and valley cross levelling data

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Geodesy and Geodynamics 2020年第3期11卷 163-173页

作者： Müge Albayrak Mustafa TevfikÖzlüdemir Mohammad Mohseni Aref Kerem Halicioglu Geomatics Engineering Istanbul Technical UniversityIstanbulTurkey School of Earth Science The Ohio Stare UniversityColumbusOHUSA Institute of Geosciences Potsdam UniversityPotsdamGermany Institute of Mathematics Freie UniversitātBerlinGermany

The Istanbul GPS Triangulation Network(IGTN) and the Istanbul Levelling Network(ILN),established in2006,provide data for the determination of a local GNSS/levelling geoid *** networks’ measurements were done separately on both the Asian and European sides of the Bosphorus Strait in the vicinity of *** connect these regions for those networks,a Valley Cross Levelling(VCL) data set,acquired in 1986 and 2004,was *** use of this VCL data set was challenging in calculating the Istanbul geoid model,primarily because of its *** this study,this challenge was overcome through newly collected VCL data in 2010,allowing for the readjustment of the ILN and the newly collected VCL data *** Istanbul geoid model was computed using soft computing techniques including the adaptive-network-based fuzzy inference system(ANFIS) and the artificial neural networks(ANNs).The resulting Istanbul GNSS/levelling geoid model is shown to be more reliable when compared with the model computed using conventional interpolation techniques.

关键词： GNSS/Icvclling geoid Valley cross levelling Soft computing techniques Interpolation techniques