Assessing Global Present‐day Surface Mass Transport and Glacial Isostatic Adjustment from Inversion of Geodetic Observations

Yan Jiang*, Xiaoping Wu, Michiel R. van den Broeke, Peter Kuipers Munneke, Sebastian B. Simonsen, Wouter van der Wal, Bert L. Vermeersen

*Corresponding author for this work

    Research output: Contribution to journalJournal articleResearchpeer-review

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    Abstract

    Long‐term monitoring of global mass transport within the Earth system improves our ability to mitigate natural hazards and better understand their relations to climate change. Satellite gravity is widely used to monitor surface mass variations for its unprecedented spatial and temporal coverage. However, the gravity data contain signals from visco‐elastic deformation in response to past ice sheet melting, preventing us from extracting signals of present‐day surface mass trend (PDMT) directly. Here we present a global inversion scheme that separates PDMT and visco‐elastic glacial isostatic adjustment (GIA) signatures by combining satellite gravimetry with satellite altimetry and ground observations. Our inversion provides global dual data coverage that enables a robust separation of PDMT and GIA spherical harmonic coefficients. It has the advantage to provide estimates of the Earth's long wavelength deformation signatures and their uncertainties. Our GIA result, along with its uncertainty estimates, can be used in future GRACE processing to better assess the impact of GIA to surface mass change. Our GIA estimates includes rapid GIA uplift in the Southeast Alaska and the Amundsen Sea Embayment, due to the visco‐elastic response to recent glacial unloading. We estimate the average surface mass change rate from 2002‐2010 to be ‐203±3 GT·a‐1 in Greenland, ‐126±18 GT·a‐1 in Antarctica and ‐62±5 GT·a‐1 in Alaska. The GIA low degree spherical harmonic coefficients are sensitive to rheological properties in Earth's deep interior. Our low‐degree GIA estimates include geocenter motion and J̇2 which provide unique constraints to understand Earth's lower mantle and ice history.
    Original languageEnglish
    Article numbere2020JB020713
    JournalJournal of Geophysical Research: Solid Earth
    Volume126
    Number of pages19
    ISSN0148-0227
    DOIs
    Publication statusPublished - 2021

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