Impact of time-dependent data assimilation on ice flow model initialization and projections: a case study of Kjer Glacier, Greenland

Details

• Journal Title:
  The Cryosphere
• Personal Author:
  Choi, Youngmin ; Seroussi, Helene ; Morlighem, Mathieu ; Schlegel, Nicole-Jeanne ; Gardner, Alex
• NOAA Program & Office:
  GFDL (Geophysical Fluid Dynamics Laboratory) ; OAR (Oceanic and Atmospheric Research)
• Description:
  Ice sheet models are often initialized with data assimilation of present-day conditions, in which unknown model parameters are estimated using the inverse method. While assimilation of snapshot observations has been widely used for regional- and large-scale ice sheet simulations, data assimilation based on time-dependent data has recently started to emerge to constrain model parameters while capturing the transient evolution of the system. However, this method has been applied only to a few glaciers with fixed ice front positions, using spatially and temporally limited observations, and has not been applied to marine-terminating glaciers of the Greenland Ice Sheet that have been retreating over the last 30 years. In this study, we assimilate time series of surface velocity into a model of Kjer Glacier in West Greenland to better capture the observed acceleration over the past 3 decades. We compare snapshot and transient inverse methods and investigate the impact of initialization procedures on the parameters inferred, as well as model projections. We find that transient-calibrated simulations better capture past trends and better reproduce changes after the calibration period, even when a short period of observations is used. The results show the feasibility and clear benefits of a time-dependent data assimilation for initializing ice sheet models. This approach is now possible with the development of longer observational records, though it remains computationally challenging.
• Keywords:
  Earth-Surface Processes Water Science And Technology Water Science And Technology Water Science And Technology
• Source:
  The Cryosphere, 17(12), 5499-5517
• DOI:
  https://doi.org/10.5194/tc-17-5499-2023
• ISSN:
  1994-0424
• Format:
  PDF
• Publisher:
  Copernicus GmbH
• Document Type:
  Journal Article
• License:
  https://creativecommons.org/licenses/by/4.0/
• Rights Information:
  CC BY
• Compliance:
  Library
• Main Document Checksum:
  urn:sha-512:21cb55e47200488f29015d6507e7d5d3683c0651b9aa1707fca815eb4f6152fe3e17ef501dd91a4ac7dc6b916a46c1d8bf59b8a8217027dd651137f3c02c7de6
• Download URL:
  https://repository.library.noaa.gov/view/noaa/64317/noaa_64317_DS1.pdf
• File Type:
  [PDF - 8.13 MB ]