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- Title
Inverse GIA estimates from satellite gravimetry and altimetry over Antarctica.
- Authors
Willen, Matthias Oskar; Uebbing, Bernd; Horwath, Martin; Kusche, Jürgen; Rietbroek, Roelof; Schröder, Ludwig
- Abstract
A significant contribution to rising sea level originates from the continental ice sheets. It canbe quantified using geodetic satellite methods. The separation of superimposed signals,such as present-day ice-mass change and glacial isostatic adjustment (GIA), aspart of the data processing is challenging. Commonly, this is achieved by utilizingforward-modelled information on GIA in order to correct the influence for mass-balancestudies. Here, we investigate a regional inverse approach which combines satellite gravimetryand ice-altimetry to derive the GIA signal and separate it from ice-mass changeover Antarctica. We investigate the sensitivity of the method by using differentice-altimetry products and various products to replace degree-1 and C20 coefficients inthe GRACE monthly solutions. The uncertainty of modelled firn processes arecharacterized based on differences of two surface mass balance products. Our mass-changeestimates of the Antarctic ice sheet have a range of 54 Gt a-1 for the time period2003-03–2009-10. The GIA estimate is very sensitive to large-scale biases and theircorrection. Furthermore, we show preliminary work of integrating the methodology for estimatingthe GIA signal from satellite observations into the global fingerprint inversion (Rietbroeket al., 2016). It combines GRACE and ocean-altimetry data to separate the totalsea-level change into individual mass and steric contributions. In a first step, wemake use of Antarctic ice-altimetry trends to include more realistic patterns ofice-sheet change. Second, we include ice-altimetry-derived ice-mass changes aspseudo-observations in order to constrain the Antarctic contribution to the total sea-levelchange. These results are compared with the GIA signal from forward models.
- Subjects
ANTARCTICA; GLACIAL isostasy; GRAVIMETRY; ICE sheets; ANTARCTIC ice; ALTIMETRY; GEODETIC satellites
- Publication
Geophysical Research Abstracts, 2019, Vol 21, p1
- ISSN
1029-7006
- Publication type
Article