Improved models of West Antarctic glacial isostatic adjustment through new crustal motion data
Lead Research Organisation:
Newcastle University
Department Name: Civil Engineering and Geosciences
Abstract
This project addresses the current uncertainty in the present-day contribution of the West Antarctic Ice Sheet to global sea level rise. These estimates are primarily derived from space geodetic (altimetry or time-variable gravity) measurements, with time-variable gravity data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission the only technique capable of determining ice mass balance for the entire ice sheet. Estimates of ice mass change from the total mass change (observed by GRACE) are, however, severely limited due to the large discrepancies between contemporary models of Antarctic glacial isostatic adjustment (GIA). Indeed, recent published estimates of ice mass change for West Antarctica are swamped by this uncertainty. Global Positioning System (GPS) time series offer important constraints on GIA and, indeed, GPS have been installed in a few of the critical locations. However, the current network of GPS sites in West Antarctica, whilst useful in discriminating between major differences in contemporary GIA models, is too sparse to provide the constraints required to significantly reduce the GIA uncertainty in the GRACE signal / for that a high spatial resolution of GPS sites is required. In particular, the southern Antarctic Peninsula/Ronne Ice Shelf contains a very large GRACE signal, but the current GPS station density there is too sparse to unambiguously determine the origin of the gravity change. Further rock outcrops suitable for additional data collection are available in this region and installing new, more densely spaced, continuous sites would provide the required constraints. Here, we propose to develop improved models of West Antarctic GIA through newly collected long-term GPS data, thereby allowing us to compute new accurate and precise estimates of ice mass contributions to sea level rise from West Antarctica. These results are of direct relevance to NERC's draft strategy (2007-2012) to expand on existing knowledge of the fundamental driving forces and feedbacks of the Earth system through prioritising plans to investigate how the cryosphere responds to global change.
Publications
Nield G
(2014)
Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading
in Earth and Planetary Science Letters
Bradley S
(2015)
Low post-glacial rebound rates in the Weddell Sea due to Late Holocene ice-sheet readvance
in Earth and Planetary Science Letters
Sasgen I
(2017)
Joint inversion estimate of regional glacial isostatic adjustment in Antarctica considering a lateral varying Earth structure (ESA STSE Project REGINA)
in Geophysical Journal International
Whitehouse P
(2012)
A new glacial isostatic adjustment model for Antarctica: calibrated and tested using observations of relative sea-level change and present-day uplift rates A new GIA model for Antarctica
in Geophysical Journal International
Koulali A
(2021)
Modelling quasi-periodic signals in geodetic time-series using Gaussian processes
in Geophysical Journal International
Wolstencroft M
(2015)
Uplift rates from a new high-density GPS network in Palmer Land indicate significant late Holocene ice loss in the southwestern Weddell Sea
in Geophysical Journal International
Vardic K
(2022)
A GNSS velocity field for crustal deformation studies: The influence of glacial isostatic adjustment on plate motion models
in Geophysical Journal International
Thomas I
(2011)
Widespread low rates of Antarctic glacial isostatic adjustment revealed by GPS observations ANTARCTIC GLACIAL ISOSTATIC ADJUSTMENT
in Geophysical Research Letters
Koulali A
(2022)
GPS-Observed Elastic Deformation Due to Surface Mass Balance Variability in the Southern Antarctic Peninsula
in Geophysical Research Letters
Goebell S
(2011)
Effects of azimuthal multipath asymmetry on long GPS coordinate time series
in GPS Solutions
Description | Initial findings show that previous computer models of crustal uplift in the southern Antarctic Peninsula, over-predict the amount of uplift there. This is important, as these models are used in computing ice being gained or lost from Antarctica using satellite-based gravity measurements. |
Exploitation Route | This research will enable more accurate estimates of Antarctica's contribution to sea-level change. The derived velocities will be used to produce a new and more accurate model of glacial isostatic adjustment. |
Sectors | Environment |
Description | Defining models of glacial isostatic adjustment in West Antarctica and Antarctic Peninsula (UKANET): better constraints on Earth structure and uplift |
Amount | £114,432 (GBP) |
Funding ID | NE/L006294/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 07/2014 |
End | 12/2018 |
Description | Quantifying West Antarctic mantle viscosity via precise GPS measurement of Earth's response to surface mass balance anomalies |
Amount | £628,391 (GBP) |
Funding ID | NE/R002029/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 01/2018 |
End | 12/2025 |
Description | Resolving Antarctic ice mass TrEndS (RATES) |
Amount | £154,675 (GBP) |
Funding ID | NE/I027681/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 02/2012 |
End | 05/2015 |
Title | Altimetry, gravimetry, GPS and viscoelastic modelling data for the joint inversion for glacial isostatic adjustment in Antarctica (ESA STSE Project REGINA), links to data files |
Description | A major uncertainty in determining the mass balance of the Antarctic ice sheet from measurements of satellite gravimetry, and to a lesser extent satellite altimetry, is the poorly known correction for the ongoing deformation of the solid Earth caused by glacial isostatic adjustment (GIA). In the past decade, much progress has been made in consistently modelling the ice sheet and solid Earth interactions; however, forward-modelling solutions of GIA in Antarctica remain uncertain due to the sparsity of constraints on the ice sheet evolution, as well as the Earth's rheological properties. An alternative approach towards estimating GIA is the joint inversion of multiple satellite data - namely, satellite gravimetry, satellite altimetry and GPS, which reflect, with different sensitivities, trends of recent glacial changes and GIA. Crucial to the success of this approach is the accuracy of the space-geodetic data sets. Here, we present reprocessed rates of surface-ice elevation change (Envisat/ICESat; 2003-2009), gravity field change (GRACE; 2003-2009) and bedrock uplift (GPS; 1995-2013). The data analysis is complemented by the forward-modelling of viscoelastic response functions to disc load forcing, allowing us to relate GIA-induced surface displacements with gravity changes for different rheological parameters of the solid Earth. The data and modelling results presented here form the basis for the joint inversion estimate of present-day ice-mass change and GIA in Antarctica. This paper presents the first of two contributions summarizing the work carried out within a European Space Agency funded study, REGINA, (http://www.regina-science.eu). |
Type Of Material | Database/Collection of data |
Year Produced | 2017 |
Provided To Others? | Yes |
Impact | n/a |
URL | https://doi.pangaea.de/10.1594/PANGAEA.875745 |
Title | British Antarctic Survey GPS Network - BREN-Brennecke Nunataks P.S., UNAVCO, GPS/GNSS Observations Dataset |
Description | GPS/GNSS station: Long-term continuous or semi-continuous occupation at a single location |
Type Of Material | Database/Collection of data |
Year Produced | 2013 |
Provided To Others? | Yes |
Impact | n/a |
URL | https://doi.org/10.7283/T52V2D7X |
Title | CAPGIA - West Antarctica Continuous Network, UNAVCO, GPS/GNSS Observations (Aggregation of Multiple Datasets) |
Description | GPS/GNSS stations: Long-term continuous or semi-continuous occupations at multiple locations |
Type Of Material | Database/Collection of data |
Year Produced | 2013 |
Provided To Others? | Yes |
Impact | n/a |
URL | https://doi.org/10.7283/T56Q1VN5 |
Description | REGINA |
Organisation | Helmholtz Association of German Research Centres |
Department | German Research Centre for Geosciences |
Country | Germany |
Sector | Private |
PI Contribution | GPS analysis |
Collaborator Contribution | Radar and laser altimetry analysis; gravity field analysis; geophysical modelling |
Impact | ESA internal reports. Journal articles Sasgen et al (2017, 2018) |
Start Year | 2012 |