Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling

Identifying errors (blunders and systematic errors) in coastal geodetic levelling networks has often been problematic. This is because (1) mean sea level (MSL) at tide gauges cannot be directly compared to height differences from levelling because the geoid/quasigeoid and MSL are not parallel, being...

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Main Author: Filmer, Michael
Format: Journal Article
Published: Taylor and Francis 2014
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/6117
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author Filmer, Michael
author_facet Filmer, Michael
author_sort Filmer, Michael
building Curtin Institutional Repository
collection Online Access
description Identifying errors (blunders and systematic errors) in coastal geodetic levelling networks has often been problematic. This is because (1) mean sea level (MSL) at tide gauges cannot be directly compared to height differences from levelling because the geoid/quasigeoid and MSL are not parallel, being separated by the ocean’s mean dynamic topography (MDT) and (2) the lack of redundancy at the edge of the levelling network. This paper sets out a methodology to independently identify blunders and/or systematic errors (over long distances) in geodetic levelling using MDT models to account for the separation between the geoid/quasigeoid and MSL at tide gauges. This method is then tested in a case study using an oceanographic MDT model, MSL observations, GNSS data and a quasigeoid model. The results are significant because the errors found could not be detected by standard levelling misclosure checks alone, with supplementary data from an MDT model, with cross-validation from GNSS-quasigeoid allowing their detection. In addition, it appears that an oceanographic-only MDT is as effective as GNSS and a quasigeoid model for detecting levelling errors, which could be particularly useful for countries with coastal levelling errors in their levelling networks that cannot be identified by conventional levelling closure checks.
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spelling curtin-20.500.11937-61172017-09-13T14:42:52Z Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling Filmer, Michael coastal mean dynamic topography CARS2009 mean sea level geodetic levelling Australia geoid Identifying errors (blunders and systematic errors) in coastal geodetic levelling networks has often been problematic. This is because (1) mean sea level (MSL) at tide gauges cannot be directly compared to height differences from levelling because the geoid/quasigeoid and MSL are not parallel, being separated by the ocean’s mean dynamic topography (MDT) and (2) the lack of redundancy at the edge of the levelling network. This paper sets out a methodology to independently identify blunders and/or systematic errors (over long distances) in geodetic levelling using MDT models to account for the separation between the geoid/quasigeoid and MSL at tide gauges. This method is then tested in a case study using an oceanographic MDT model, MSL observations, GNSS data and a quasigeoid model. The results are significant because the errors found could not be detected by standard levelling misclosure checks alone, with supplementary data from an MDT model, with cross-validation from GNSS-quasigeoid allowing their detection. In addition, it appears that an oceanographic-only MDT is as effective as GNSS and a quasigeoid model for detecting levelling errors, which could be particularly useful for countries with coastal levelling errors in their levelling networks that cannot be identified by conventional levelling closure checks. 2014 Journal Article http://hdl.handle.net/20.500.11937/6117 10.1080/01490419.2013.868383 Taylor and Francis fulltext
spellingShingle coastal mean dynamic topography
CARS2009
mean sea level
geodetic levelling
Australia
geoid
Filmer, Michael
Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling
title Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling
title_full Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling
title_fullStr Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling
title_full_unstemmed Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling
title_short Using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling
title_sort using models of the ocean's mean dynamic topography to identify errors in coastal geodetic levelling
topic coastal mean dynamic topography
CARS2009
mean sea level
geodetic levelling
Australia
geoid
url http://hdl.handle.net/20.500.11937/6117