CSDMS 2014 annual meeting - Uncertainty and Sensitivity in Surface Dynamics Modeling

Towards better quantifications of the uncertainty in polar ice-sheet projections using the open source framework ISSM

Eric Larour

Jet Propulsion Laboratory, United States
Helene Seroussi Jet Propulsion Laboratory United States
Mathieu Morlighem University of California United States
Eric Rignot University of California United States
Nicole Schlegel Jet Propulsion Laboratory United States

Understanding and modeling the evolution of continental ice sheets such as Antarctica and Greenland can be a difficult task because a lot of the inputs used in transient ice flow models, either inferred from satellite or in-situ observations, carry large measurement errors that will propagate forward and impact projection assessments. Here, we aim at comprehensively quantifying error margins on model diagnostics such as mass outflux at the grounding line, maximum surface velocity and overall ice-sheet volume, applied to major outlet glaciers in Antarctica and Greenland. Our analysis relies on uncertainty quantification methods implemented in the Ice Sheet System Model (ISSM), developed at the Jet Propulsion Laboratory in collaboration with the University of California at Irvine. We focus in particular on sensitivity analysis to try and understand the local influence of specific inputs on model results, and sampling analysis to quantify error margins on model diagnostics. Our results demonstrate the expected influence of measurement errors in surface altimetry, bedrock position and basal friction

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Of interest for:
  • Terrestrial Working Group
  • Marine Working Group