REGINA status update, 21 May 2015 Page 1 Regional glacial isostatic adjustment and CryoSat elevation rate corrections in Antarctica (REGINA) – Supplementary Study Contract-Nr.: /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) 1 st order GIA estimate (difference phase 1 and 2) Impact of altimetry on GIA estimate
REGINA status update, 21 May 2015 Page 3 Altimetry annual rates
REGINA status update, 21 May 2015 Page 4 Cluster analysis of GPS Raw data shown here → Symbol area inversely proportional to error. Discrepant sites in a region are often lower quality. Weighted average of nearby sites will be minimally affected by low-quality data.
REGINA status update, 21 May 2015 Page 5 Clustered GPS data Iterative clustering of sites up to 200 km separation. No threshold for velocity diff. Weighted mean of velocities, simple mean of site coords in each cluster. Far fewer regional discrepancies.
REGINA status update, 21 May 2015 Page 6 GIA estimate (du/dt)
REGINA status update, 21 May 2015 Page 7 GIA estimate (de/dt)
REGINA status update, 21 May 2015 Page 8 Comparison: Phase 1 and Phase 2 Phase 1Phase GRACEAltimetry
REGINA status update, 21 May 2015 Page 9 dh/dt Amundsen Sea Embayment (ASE) Phase 1Phase Phase
REGINA status update, 21 May 2015 Page 10 Comparison: Phase 1 and Phase 2 Uniform errors of annual rates Uniform density: 910 kg/m³ 1 st order GIA estimate: “GRACE minus altimetry”
REGINA status update, 21 May 2015 Page 11 Comparison: Phase 1 and Phase 2 1 st order GIA estimate: “GRACE minus altimetry” Non-uniform errors of dh/dt annual rates Uniform density: 910 kg/m³
REGINA status update, 21 May 2015 Page 12 Comparison: Phase 1 and Phase 2 1 st order GIA estimate: “GRACE minus altimetry” Uniform errors of dh/dt annual rates Firn & density model applied
REGINA status update, 21 May 2015 Page 13 Comparison: Phase 1 and Phase 2 1 st order GIA estimate: “GRACE minus altimetry” Uniform errors of dh/dt annual rates Firn & density model applied
REGINA status update, 21 May 2015 Page 14 Fully coupled 3D simulation Ice model: Pollard & DeConto (2009)
REGINA status update, 21 May 2015 Page 15 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 be included (CS2)?