Predicting the steady-state isochronal stratigraphy of ice shelves using observations and modeling

• Main Authors: Višnjević, Vjeran, Drews, Reinhard, Schannwell, Clemens, Koch, Inka, Franke, Steven, Jansen, Daniela, Eisen, Olaf
• Format: Text
• Language: English
• Published: 2022
• Subjects: Antarctic; The Antarctic; East Antarctica; Roi Baudouin; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://doi.org/10.5194/tc-2022-23; https://tc.copernicus.org/preprints/tc-2022-23/

Ice shelves surrounding the Antarctic perimeter decelerate ice discharge towards the ocean through buttressing. Ice-shelf evolution and integrity depend on the local surface accumulation, basal melting and on the spatially variable ice-shelf viscosity. These parameters are often poorly constrained by observations and introduce uncertainties in ice-sheet projections for the ice-sheet evolution. Isochronal radar stratigraphy is an observational archive for the atmospheric, oceanographic and ice-flow history of ice shelves with potential to assist model calibration. Here, we explore the possibility of using a simple and observationally driven ice-flow forward model to predict the ice-shelf stratigraphy for a given atmospheric- and oceanographic scenario. We validate this approach with the full Stokes ice-flow model Elmer/Ice and present a test case for the Roi Baudouin Ice Shelf (East Antarctica), where we compare model predictions with radar observations. The presented method enables us to investigate whether ice shelves are in steady-state and to delineate how much of the ice-shelf volume is determined by its local surface accumulation. This can be used to better understand variability in ice-shelf rheology and for estimations which ice shelves are particularly susceptible to changes of surface accumulation rates in the future. Moreover, the numerically efficient prediction of isochronal stratigraphy is a step forward towards integrating radar data into ice-flow models using inverse methods. This has potential to constrain ocean-induced melting beneath Antarctic ice shelves using the ever-growing archive of radar observations of internal ice stratigraphy.