GPS Imaging of Global Vertical Land Motion for Studies of Sea Level Rise

Hammond, W. C.; Blewitt, G.; Kreemer, C.; Nerem, R. S.

doi:10.1029/2021jb022355

Cited by 53 publications

(67 citation statements)

References 108 publications

(176 reference statements)

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“…Our finding of long‐term subsidence in the sector of coastal East Antarctica west of Totten Glacier builds on previous studies that have analyzed earlier records from DAV1 and BHIL, and MAW1 650 km to the west of DAV1, indicating subsidence or marginal amounts of uplift along this coastline (Argus et al., 2014; Hammond et al., 2021; Martín‐Español et al., 2016; Thomas et al., 2011). Liu et al.…”

Section: Discussionsupporting

confidence: 85%

GPS Rates of Vertical Bedrock Motion Suggest Late Holocene Ice‐Sheet Readvance in a Critical Sector of East Antarctica

King

Watson

White

2022

Geophysical Research Letters

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Models of Antarctic glacial isostatic adjustment (GIA) show substantial differences, partly because of lack of data to constrain them Whitehouse et al., 2019). These differences represent uncertainty that affects estimates of ice-sheet mass change from satellite gravimetry and, to a lesser extent, satellite altimetry-both in terms of the ice-sheet wide contribution to sea-level change, as well the contribution over regional or basin-level scales (e.g., King et al., 2012).Over the recent decade, Global Positioning System (GPS)-estimates of bedrock velocities have become increasingly important for testing the different GIA model predictions of bedrock displacement or as data to inform empirical estimates (e.g.,

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Section: Discussionsupporting

confidence: 85%

GPS Rates of Vertical Bedrock Motion Suggest Late Holocene Ice‐Sheet Readvance in a Critical Sector of East Antarctica

King

Watson

White

2022

Geophysical Research Letters

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“…The average uncertainties from our approach at GPS and TG sites were 0.65 and 0.71 mm/yr, respectively, comparable with 0.83 and 0.87 mm/yr inferred from Hector-derived (at GPS) and GPS-Krig (at TG) uncertainties, respectively. The GPS-inferred VLM field showed that the Australian plate is largely subsiding with weighted mean rates of -0.10, -0.38, -0.95 and -0.62 mm/yr in the NW, NE, SW and SE regions, respectively, in general agreement with previous GPS estimates of subsidence (Hammond et al, 2021;Riddell et al, 2020). The estimates at TGs revealed localized VLM trends around the continent that are not completely consistent with the GPS-Krig interpolations.…”

Section: Linear Vlmsupporting

confidence: 78%

“…GPS observations of VLM across Australia suggest the continent is subsiding overall (Hammond et al, 2021;King et al, 2012;Riddell et al, 2020). Recent work by Riddell et al (2020) using GPS time series showed the widespread pattern of subsidence cannot be fully explained by GIA.…”

Section: Introductionmentioning

confidence: 99%

Vertical Deformation and Residual Altimeter Systematic Errors around Continental Australia Inferred from a Kalman-Based Approach

Rezvani¹,

Watson²,

King³

2021

Preprint

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We further developed a space-time Kalman approach to estimate time-variable signals in residual altimeter systematic errors and vertical land motion (VLM) around the Australian coast since the 1990s, through combining multi-mission absolute sea-level (ASL), relative sea-level (RSL) from tide gauges (TGs) and GPS heights records. Our results confirmed continent-wide subsidence and TG-specific VLMs yielding a ~40% reduction in RMSE of geographical ASL variability, compared with rates determined using spatially interpolated GPS velocities that fail to capture localized trends by up to ~1.5 mm/yr. Stacked time series of non-linear deformation at TGs and nearby GPS showed some correlation, suggesting the technique was partially successful in reflecting the surface loading. Site-by-site inspection revealed spurious non-linearity likely caused by residual oceanographic signals present between the TG and altimeter measurement locations. Our average mission-specific error estimates are small but significant, typically within ~±0.5-1.0 mm/yr, with negligible effect implied on the overall rate of ASL. Analysis of the time variability of altimeter errors confirmed stability for most missions except for Jason-2 with an anomaly reaching ~2.8 mm/yr in the first ~3.5 years of operation which is supported by analysis from the Bass Strait altimeter validation facility. Weak correlation with the dominant climate mode suggests potential deficiencies in the resolution of the time-variable gravity field used for orbit determination as a possible cause, yet other drivers cannot be discounted. Our approach advances the ability to estimate TG-specific VLMs and regional altimeter systematic errors, and highlights that residual oceanographic signals remain a fundamental limitation to such techniques.

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“…It would be impossible to obtain sufficient data without complementary space-geodetic techniques. For instance, non-linear VLM can be estimated from global navigation satellite system (GNSS) station time series [9][10][11] and interferometric synthetic aperture radar (InSAR) analysis [7,12,13]. Due to the non-linearity of the VLM, however, observed motions cannot be extrapolated to the past or future.…”

Section: Introductionmentioning

confidence: 99%

“…The Fennoscandian Shield (including the whole Baltic Sea region) in Northern Europe is an area of a relatively low temporal VLM variability [11]. The primary cause for VLM is GIA [16,26,27], whereas the contribution from seasonal and nonseasonal velocity variability to VLM is typically modest [11]. Furthermore, the estimated current GIA deceleration of 0.002 mm/y 2 can be considered negligible [28].…”

Section: Introductionmentioning

confidence: 99%

Treatment of Tide Gauge Time Series and Marine GNSS Measurements for Vertical Land Motion with Relevance to the Implementation of the Baltic Sea Chart Datum 2000

et al. 2022

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Tide gauge (TG) time series and GNSS measurements have become standard datasets for various scientific and practical applications. However, the TG and geodetic networks in the Baltic Sea region are deforming due to vertical land motion (VLM), the primary cause of which is the glacial isostatic adjustment. Consequently, a correction for VLM, either obtained from a suitable VLM model or by utilizing space-geodetic techniques, must be applied to ensure compatibility of various data sources. It is common to consider the VLM rate relative to an arbitrary reference epoch, but this also yields that the resulting datasets may not be directly comparable. The common height reference, Baltic Sea Chart Datum 2000 (BSCD2000), has been initiated to facilitate the effective use of GNSS methods for accurate navigation and offshore surveying. The BSCD2000 agrees with the current national height realizations of the Baltic Sea countries. As TGs managed by national authorities are rigorously connected to the national height systems, the TG data can also be used in a common system. Hence, this contribution aims to review the treatment of TG time series for VLM and outline potential error sources for utilizing TG data relative to a common reference. Similar consideration is given for marine GNSS measurements that likewise require VLM correction for some marine applications (such as validating marine geoid models). The described principles are illustrated by analyzing and discussing numerical examples. These include investigations of TG time series and validation of shipborne GNSS determined sea surface heights. The latter employs a high-resolution geoid model and hydrodynamic model-based dynamic topography, which is linked to the height reference using VLM corrected TG data. Validation of the presented VLM corrected marine GNSS measurements yields a 1.7 cm standard deviation and –2.7 cm mean residual. The estimates are 1.9 cm and –10.2 cm, respectively, by neglecting VLM correction. The inclusion of VLM correction thus demonstrates significant improvement toward data consistency. Although the focus is on the Baltic Sea region, the principles described here are also applicable elsewhere.

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GPS Imaging of Global Vertical Land Motion for Studies of Sea Level Rise

Cited by 53 publications

References 108 publications

GPS Rates of Vertical Bedrock Motion Suggest Late Holocene Ice‐Sheet Readvance in a Critical Sector of East Antarctica

GPS Rates of Vertical Bedrock Motion Suggest Late Holocene Ice‐Sheet Readvance in a Critical Sector of East Antarctica

Vertical Deformation and Residual Altimeter Systematic Errors around Continental Australia Inferred from a Kalman-Based Approach

Treatment of Tide Gauge Time Series and Marine GNSS Measurements for Vertical Land Motion with Relevance to the Implementation of the Baltic Sea Chart Datum 2000

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