AUSGeoid09: a more direct and more accurate model for converting ellipsoidal heights to AHD heights

Brown, N. J.; Featherstone, Will; Hu, G.; Johnston, Gary

doi:10.1080/14498596.2011.580498

Cited by 17 publications

(23 citation statements)

References 19 publications

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“…2.4) were used to calculate a geometric component (cf. Brown et al 2011) that models the difference between the a priori gravimetric quasigeoid and the AHD. This is dominated by a north-south tilt (cf.…”

Section: Gravity Datamentioning

confidence: 99%

“…Brown et al 2011). A near-nationwide dataset of GNSS-levelling points was provided by Australian State and Territory geodetic agencies (Sect.…”

Section: Gnss-levelling Datamentioning

confidence: 99%

“…The north-south tilt and regional distortions in the AHD necessitate the geometric component (cf. Brown et al 2011) for the transformation of GNSS ellipsoidal heights to the AHD, until the time that the AHD is redefined. Table 4 shows that, when assessing the gravimetric quasigeoid models against the Australian GNSS-levelling data, there is only a very marginal improvement upon EGM2008.…”

Section: Modified Stokes Parameter Sweepsmentioning

confidence: 99%

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The first Australian gravimetric quasigeoid model with location-specific uncertainty estimates

Featherstone

McCubbine

Brown

et al. 2017

J Geod

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We describe the computation of the first Australian quasigeoid model to include error estimates as a function of location that have been propagated from uncertainties in the EGM2008 global model, land and altimeterderived gravity anomalies and terrain corrections. The model has been extended to include Australia's offshore territories and maritime boundaries using newer datasets comprising an additional ∼280,000 land gravity observations, a newer altimeter-derived marine gravity anomaly grid, and terrain corrections at 1 × 1 resolution. The error propagation uses a remove-restore approach, where the EGM2008 quasigeoid and gravity anomaly error grids are augmented by errors propagated through a modified Stokes integral from the errors in the altimeter gravity anomalies, land gravity observations and terrain corrections. The gravimetric quasigeoid errors (one sigma) are 50-60 mm across most of the Australian landmass, increasing to ∼100 mm in regions of steep horizontal gravity gradients or the mountains, and are commensurate with external estimates.

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Section: Gravity Datamentioning

confidence: 99%

“…Brown et al 2011). A near-nationwide dataset of GNSS-levelling points was provided by Australian State and Territory geodetic agencies (Sect.…”

Section: Gnss-levelling Datamentioning

confidence: 99%

Section: Modified Stokes Parameter Sweepsmentioning

confidence: 99%

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The first Australian gravimetric quasigeoid model with location-specific uncertainty estimates

Featherstone

McCubbine

Brown

et al. 2017

J Geod

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Section: Introductionmentioning

confidence: 99%

“…In the Australian context, AUSGeoid09 is the latest quasigeoid model that best ts AHD [1,9]. While the performance of AUSGeoid09, along with the improvements it provides over its predecessor AUSGeoid98, have been investigated previously [1,18], these studies have not focused on mountainous regions. Considering that gravity can change dramatically within a few kilometres on the earth's surface in Australia [3], especially in mountainous terrain, and that observed gravity data are generally sparse in these areas, it is necessary to evaluate mountainous regions in particular.…”

Section: Introductionmentioning

confidence: 99%

Absolute Performance of AUSGeoid09 in Mountainous Regions

Sussanna¹,

Janssen²,

Gibbings

2014

Journal of Applied Geodesy

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Abstract:The Australian Height Datum (AHD) is the current national vertical datum for Australia, and AUSGeoid09 is the latest quasigeoid model used to compute (normal-orthometric) AHD heights from Global Navigation Satellite System (GNSS) derived ellipsoidal heights. While previous studies have evaluated the AUSGeoid09 model across Australia, such studies have not focused on mountainous regions in particular. This paper investigates the performance of AUSGeoid09 in an absolute sense in the Mid Hunter and Snowy Mountains regions of New South Wales. Absolute (i.e. single point) comparisons were undertaken between AUSGeoid09-derived heights and published AHD heights. The performance of AUSGeoid09 was evaluated relative to its predecessor AUSGeoid98. In both study areas, an overall improvement is evident when applying AUSGeoid09 to compute AHD heights in an absolute sense. In the Mid Hunter, AUSGeoid09 provided a substantial improvement over its predecessor, clearly demonstrating the bene ts of its new geometric component on GNSS-derived AHD height determination. In the Snowy Mountains, moderate improvement over AUSGeoid98 was evident. However, a slope was detected for AUSGeoid09 residuals, and it appears that the geometric component may have overcompensated for sea surface topography in this area. While this appraisal of AUSGeoid09 performance in mountainous regions is encouraging, it has been shown that some discrepancies still remain between AUSGeoid09-derived heights and AHD. Eventually, a new vertical datum will be necessary to ensure homogeneity across Australia.

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Spatial and temporal patterns of Australian dynamic topography from River Profile Modeling

Czarnota

Roberts

White

et al. 2014

J. Geophys. Res. Solid Earth

128

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Despite its importance, the temporal and spatial evolution of continental dynamic topography is poorly known. Australia's isolation from active plate boundaries and its rapid northward motion within a hot spot reference frame make it a useful place to investigate the interplay between mantle convection, topography, and drainage. Offshore, dynamic topography is relatively well constrained and can be accounted for by Australia's translation over the mantle's convective circulation. To build a database of onshore constraints, we have analyzed an inventory of longitudinal river profiles, which is sensitive to uplift rate history. Using independently constrained erosional parameters, we determine uplift rates by minimizing the misfit between observed and calculated river profiles. Resultant fits are excellent and calculated uplift histories match independent geologic constraints. We infer that western and central Australia underwent regional uplift during the last 50 Myr and that the Eastern Highlands have been uplifted in two stages. The first stage from 120 to 80 Ma, coincided with rifting along the eastern margin and its existence is supported by thermochronological measurements. A second stage occurred at 80–10 Ma, formed the Great Escarpment, and coincided with Cenozoic volcanism. The relationship between topography, gravity anomalies, and shear wave tomographic models suggest that regional elevation is supported by temperature anomalies within the lithosphere's thermal boundary layer. Morphology and stratigraphy of the Eastern Highlands imply that these anomalies have been coupled to the base of the plate during Australia's northward motion over the last 70 Myr.

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AUSGeoid09: a more direct and more accurate model for converting ellipsoidal heights to AHD heights

Cited by 17 publications

References 19 publications

The first Australian gravimetric quasigeoid model with location-specific uncertainty estimates

The first Australian gravimetric quasigeoid model with location-specific uncertainty estimates

Absolute Performance of AUSGeoid09 in Mountainous Regions

Spatial and temporal patterns of Australian dynamic topography from River Profile Modeling

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