REGINA status update, 21 May 2015 Page 1 Regional glacial isostatic adjustment and CryoSat elevation...
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Transcript of REGINA status update, 21 May 2015 Page 1 Regional glacial isostatic adjustment and CryoSat elevation...
REGINA status update, 21 May 2015 Page 1
Regional glacial isostatic adjustment andCryoSat elevation rate corrections in Antarctica
(REGINA) – Supplementary StudyContract-Nr.: 4000107393/12/I-NB
REGINA Status Update 22 May 2015
STSE: CryoSat + Cryosphere
REGINA status update, 21 May 2015 Page 2
Outline
• Characteristic of new data sets (altimetry & GPS) • 1st order GIA estimate (difference phase 1 and 2)• Impact of altimetry on GIA estimate
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Altimetry annual rates
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Cluster analysis of GPS
Raw data shown here →Symbol area inversely proportional to error.
Discrepant sites in a regionare often lower quality.
Weighted average of nearbysites will be minimallyaffected by low-quality data.
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Clustered GPS data
Iterative clustering of sitesup to 200 km separation.
No threshold for velocity diff.
Weighted mean of velocities,simple mean of site coordsin each cluster.
Far fewer regional discrepancies.
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GIA estimate (du/dt)
2003-2009
2003-2013
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GIA estimate (de/dt)
2003-2009 2003-2013
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Comparison: Phase 1 and Phase 2
Phase 1 Phase 2
2003-2009GRACEAltimetry
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dh/dt Amundsen Sea Embayment (ASE)
Phase 1 Phase 2
2003-2009
Phase 2
2003-2013
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Comparison: Phase 1 and Phase 2
Uniform errors of annual rates
Uniform density: 910 kg/m³
1st order GIA estimate: “GRACE minus altimetry”2003-2009
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Comparison: Phase 1 and Phase 2
1st order GIA estimate: “GRACE minus altimetry”
Non-uniform errors of dh/dt annual rates
Uniform density: 910 kg/m³
2003-2009
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Comparison: Phase 1 and Phase 2
1st order GIA estimate: “GRACE minus altimetry”
Uniform errors of dh/dt annual rates
Firn & density model applied
2003-2009
REGINA status update, 21 May 2015 Page 13
Comparison: Phase 1 and Phase 2
1st order GIA estimate: “GRACE minus altimetry”
Uniform errors of dh/dt annual rates
Firn & density model applied
2003-2013
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Fully coupled 3D simulation
Ice model: Pollard & DeConto (2009)
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Discussion
Where do dh/dt differences come from?How can density model for Amundsen Sea Embayment be improved?What could be best way to constrain GIA estimate:• Introduction of a priori constraint on GIA / past loading• Force smoothness of recovered field?• A posteriori limitation of spectral range?Should 2010-2013 be included (CS2)?