W 0 Estimates in the Frame of the GGOS Working Group on Vertical Datum Standardisation

Sánchez, Laura; Dayoub, Nadim; Čunderlík, Róbert; Minarechová, Zuzana; Mikula, Karol; Vatrt, Viliam; Vojtíšková, Marie; Šíma, Z.

doi:10.1007/978-3-319-10837-7_26

Cited by 13 publications

(10 citation statements)

References 22 publications

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“…A closer look at the estimated δW 0 s reveals that unlike the previous studies that examined other approaches to estimate W 0 (Sánchez 2007;Burša et al 2007a;Dayoub et al 2012;Sánchez et al 2014Sánchez et al , 2016, only satellite-based coefficients of the GGM do not suffice to estimate W 0 . It is mainly due to taking into account land areas in our computations based on our approach.…”

Section: Influence Of the Omission Error Of The Ggm In The Estimationmentioning

confidence: 74%

A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters

Amin

Sjöberg

Bagherbandi

2019

J Geod

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The geoid, according to the classical Gauss-Listing definition, is, among infinite equipotential surfaces of the Earth's gravity field, the equipotential surface that in a least squares sense best fits the undisturbed mean sea level. This equipotential surface, except for its zero-degree harmonic, can be characterized using the Earth's global gravity models (GGM). Although, nowadays, satellite altimetry technique provides the absolute geoid height over oceans that can be used to calibrate the unknown zerodegree harmonic of the gravimetric geoid models, this technique cannot be utilized to estimate the geometric parameters of the mean Earth ellipsoid (MEE). The main objective of this study is to perform a joint estimation of W 0 , which defines the zero datum of vertical coordinates, and the MEE parameters relying on a new approach and on the newest gravity field, mean sea surface and mean dynamic topography models. As our approach utilizes both satellite altimetry observations and a GGM model, we consider different aspects of the input data to evaluate the sensitivity of our estimations to the input data. Unlike previous studies, our results show that it is not sufficient to use only the satellite-component of a quasi-stationary GGM to estimate W 0 . In addition, our results confirm a high sensitivity of the applied approach to the altimetry-based geoid heights, i.e., mean sea surface and mean dynamic topography models. Moreover, as W 0 should be considered a quasi-stationary parameter, we quantify the effect of time-dependent Earth's gravity field changes as well as the time-dependent sea level changes on the estimation of W 0 . Our computations resulted in the geoid potential W 0 62636848.102 ± 0.004 m 2 s −2 and the semi-major and minor axes of the MEE, a 6378137.678 ± 0.0003 m and b 6356752.964 ± 0.0005 m, which are 0.678 and 0.650 m larger than those axes of GRS80 reference ellipsoid, respectively. Moreover, a new estimation for the geocentric gravitational constant was obtained as GM (398600460.55 ± 0.03) × 10 6 m 3 s −2 .

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Section: Influence Of the Omission Error Of The Ggm In The Estimationmentioning

confidence: 74%

A global vertical datum defined by the conventional geoid potential and the Earth ellipsoid parameters

Amin

Sjöberg

Bagherbandi

2019

J Geod

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“…Em uma visão moderna, o Datum Vertical (DV) deve ser relacionado com uma referência global única, tal como previsto na Resolução n° 1 da International Association Geodesy (IAG) que estabeleceu, em julho de 2015, o IHRS (IAG, 2015 baseado em um valor unívoco de geopotencial e que as coordenadas verticais primárias nas Redes Verticais de Referência (RVRs) sejam os números geopotenciais. A questão do valor unívoco foi discutida em Sánchez et al (2012). As exigências atuais relativamente aos SVRs e RVRs têm sua fundamentação expressa principalmente nos pressupostos do GGOS.…”

Section: Demandas Globais Para Referencial Verticalunclassified

Análise da Evolução Temporal do Datum Vertical Brasileiro de Imbituba

Silva¹,

Freitas²

2019

rcar

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Actualmente, los temas más centrales de Geodesia se vinculan a la provisión de un Sistema de Referencia Global único, al que puedan vincularse de forma unívoca y con exactitud los cambios globales de carácter geométrico y físico. El Global Geodetic Reference Frame tiene como objetivo la mejor estructuración de los Sistemas de Observación de la Tierra actualmente con perspectivas de la determinación de los cambios globales al nivel de una parte por mil millones, considerando varios parámetros geométricos y físicos. En este contexto, se pretende que el International Height Reference Frame, realizado por International Height Reference System, posea consistencia global de, por lo menos, un centímetro en su realización y control espacio/temporal en el orden del milímetro por año. Considerando estos aspectos, análisis y evolución temporal del Datum Vertical Brasileño de Imbituba utilizando datos mareográficos del nivel del mar de: Permanent Service for Mean Sea Level (1948 a 1968), University of Hawaii Sea Level Center (2001 a 2007) y Red Mareográfica Permanente para Geodésia (2006 a 2016), y datos de distintas misiones altimétricas del período 1991 a 2015 obtenidos del Banco de Datos del Deutsches Geodätisches Forschungsinstitut. Así como, datos de posicionamiento continuo GNSS del período de 2007 a 2016, de la Red Brasileña de Monitoreo Continuo, los cuales fueron utilizados para modelado de los movimientos locales de la corteza. Los resultados permitirán discriminar los movimientos de la corteza en relación al nivel del mar. Para esto, se utilizó la tendencia de variación del nivel del mar evidenciado por el mareógrafo, así como la variación del componente vertical obtenido con el procesamiento GNSS y de la Sea Surface Height obtenida de los datos de los satélites altimétricos.

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“…Today, the estimation of a global W 0 is based on the combination of mean sea surface models derived from satellite altimetry observations and the Earth's gravity field modeling derived from space techniques, in particular low Earth orbiting satellites like GRACE, GOCE, and the satellites for laser ranging observations like LAGEOS, ETALON, etc. [e.g., Burša et al 2007;Dayoub et al 2012;Sánchez 2012;Sánchez et al 2014]. …”

Section: Geopotential Value Wmentioning

confidence: 99%

“…The IAG conventional W 0 value (62 636 853.4 m 2 s −2 ) relies on the newest (as of 2013) gravity field and sea surface models and its computation is supported by detailed conventions considering [see Sánchez et al 2015]: (1) sensitivity of W 0 to the Earth's gravity field modeling (especially omission and commission errors and time-dependent Earth's gravity field changes); (2) sensitivity of W 0 to the mean sea surface modeling (e.g. geographical coverage, time-dependent sea surface variations, accuracy of the mean sea surface heights); (3) dependence of W 0 on the tide system; and (4) weighted computation based on the input data quality.…”

Section: Geopotential Value Wmentioning

confidence: 99%