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- Permanent Link:
- http://dpanther.fiu.edu/dpService/dpPurlService/purl/FI15062163/00001
Material Information
- Title:
- Geodetic measurements of vertical crustal velocity in West Antarctica and the implications for ice mass balance
- Series Title:
- Geochemistry Geophysics Geosystems Volume 10 Number 10
- Creator:
- Bevis, Michael
Kendrick, Eric
Smalley, Robert Jr.
Dalziel, Ian
Caccamise, Dana
Sasgen, Ingo
Helsen, Michiel
Taylor, F.W.
Zhou, Hao
Brown, Abel
Raleigh, David
Willis, Michael
Wilson, Terry
Konfal, Stephanie
- Publisher:
- American Geophysical Union
- Publication Date:
- 2009
- Language:
- English
Notes
- Summary:
- The GRACE satellite mission, which measures
temporal changes in Earth’s gravity field, can infer
near-surface mass changes with unprecedented
precision, but in Antarctica (as in Greenland) these
estimates are unusually ambiguous, because
GRACE cannot distinguish between changes in
ice mass and nearby changes in rock mass associated
with postglacial rebound (PGR) [Le Meur and
Huybrechts, 2001; Velicogna and Wahr, 2002].
Therefore, numerical models of PGR are used
during or after the analysis of GRACE observations
to account for the viscous influx of rock mass
into the study area, and thereby isolate the changes
in ice mass [Velicogna and Wahr, 2006; Chen et
al., 2006; Ramillien et al., 2006, Sasgen et al.,
2007a]. Over much of Antarctica, this ‘‘PGR
correction’’ is larger than the resulting estimate of
ice mass change, sometimes much larger [Velicogna
and Wahr, 2006]. This vulnerability is worrying
because there are many disparate predictions
for contemporary uplift rates in Antarctica, and
little really firm basis for choosing between them.
For example, we contrast the predictions of PGR
models ICE-5G (VM2) [Peltier, 2004] and IJ05
(6A) [Ivins and James, 2005, see Figure 6A] in
Figure 1. These disagreements are not surprising,
since PGR models are based on (1) an ice history
model and (2) a geomechanical model (parameterized
in terms of the thickness of the lithosphere, the
underlying mantle viscosity structure, etc.), neither
of which are strongly constrained by observations.
Indeed, because PGR beneath and adjacent to an
actively evolving ice sheet is sensitive to the details
of crustal and mantle rheology, and these details
are not known with the necessary level of accuracy,
many theorists produce suites of PGR predictions
by combining a single ice history model with a set
of geomechanical scenarios [Ivins and James,
2005; Wang et al., 2008]. Predictions of PGR can
be improved by reducing the underlying uncertainties
in rock rheology (e.g., using seismology) and
ice history (e.g., using glacial geomorphology and
stratigraphy). They can also be tested and improved
by utilizing geodetic observations of crustal
motion [Milne et al., 2004], which is our approach. ( English )
Record Information
- Source Institution:
- Florida International University
- Rights Management:
- Please contact the owning institution for licensing and permissions. It is the user's responsibility to ensure use does not violate any third party rights.
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