Geodetic observations for constraining mantle processes in Antarctica

Abstract

Geodynamic processes in Antarctica such as glacial isostatic adjustment (GIA) and post-seismic deformation are measured by geodetic observations such as GNSS and satellite gravimetry. GNSS measurements have been comprising continuous measurements as well as episodic measurements since the mid-1990s. The estimated velocities typically reach an accuracy of 1 mm/a for horizontal and 2 mm/a for vertical velocities. However, the elastic deformation due to present-day ice-load change needs to be considered accordingly.Space gravimetry derives mass changes from small variations in the inter-satellite distance of a pair of satellites, starting with the GRACE satellite mission in 2002 and continuing with the GRACE-FO mission launched in 2018. The spatial resolution of the measurements is low (about 300 km) but the measurement error is homogeneous across Antarctica. The estimated trends contain signals from ice mass change, local and global GIA signal. To combine the strengths of the individual data sets statistical combinations of GNSS, GRACE and satellite altimetry data have been developed. These combinations rely on realistic error estimates and assumptions of snow density. Nevertheless, they capture signal that is missing from geodynamic forward models such as the large uplift in the Amundsen Sea sector due to low-viscous response to century-scale ice-mass changes.

An introduction to the geochemistry and geophysics of the Antarctic mantle

“…Both the historical overview and the chapters in this volume show how concerted efforts such as the International Polar Year have increased our knowledge of the Antarctic mantle. Technological developments are also an important driver for Antarctic Earth science, from lower detection limits in geochemical studies (Handler et al 2021), novel isotopic studies (Martin 2021) and micro-fabric studies (Chatzaras and Kruckenberg 2021), and better stand-alone GNSS instruments (Scheinert et al 2021) to more precise magnetotelluric measurements (Wannamaker et al 2021) and satellite measurements (Pappa and Ebbing 2021). This in turn drove the developments of numerical models for mantle composition (Wiens et al 2021), rheology (Ivins et al 2021) or mantledynamics studies that can integrate those measurements (van der Wal et al 2022).…”

“…Geodetic measurements can detect the response to past ice-sheet-thickness changes in terms of crustal motion or gravity change. Scheinert et al (2021) explain the processing procedure and the importance of correcting for the effect of current ice-sheet changes. They review regional studies in the Amundsen Sea sector and the Antarctic Peninsula, where fast relaxation is detected.…”

Modeling Viscoelastic Solid Earth Deformation Due To Ice Age and Contemporary Glacial Mass Changes in ASPECT

“…Near areas of past and current ice cover, it is commonly thought that solid Earth ground motion results from a combination of (a) a viscous response to past ice load changes, and (b) an elastic response to contemporary ice load changes. Consequently, these geodetic measurements are either (a) corrected for the viscous response to past ice load changes, based on GIA modeling, and the remaining (assumed elastic) signal is used to constrain contemporary ice load changes (e.g., Bevis et al., 2012; Simpson et al., 2011; The IMBIE Team, 2018, 2019) or (b) corrected for the elastic response to contemporary ice load changes and the remaining viscous signal is used to constrain Earth material properties (Scheinert et al., 2021, and references therein), such as mantle viscosity and lithospheric thickness, or ice sheet histories, also using GIA models.…”

Terrestrial water storage anomaly estimating using machine learning techniques and satellite‐based data (a case study of Lake Urmia Basin)

“…The distribution of mass on the Earth is subject to constant change due to a variety of factors. This includes ocean tides, alterations in the solid composition of the planet, atmospheric fluctuations resulting from minor storms and seasonal shifts in climate (Scheinert et al, 2021). Small changes in the mass distribution on the Earth can cause significant changes in the Earth's gravity, which can be detected by satellites and groundbased measuring equipment (Wang et al, 2022).…”