Simulation of ice sheet / sea-level feedbacks with a coupled ice sheet / solid Earth model

• Applicant: Dr. Ingo Sasgen
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography ; Palaeontology
• Term: from 2013 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 248087342

• Final Report Year: 2015

Final Report Abstract

Both of our studies have shown the importance of a thorough treatment of the solid Earth when simulating the AIS through periods of millennial time scales, and we suggest that similar studies can be undertaken in order to test this for the Northern hemispheric paleo ice sheets, such as the Laurentide Ice Sheet or the Barents Sea Ice Sheet, which both featured significant portions of grounded ice below sea level and therefore should be affected by these mechanisms of ice/Earth interplay. However, the importance of the ice / solid Earth feedback depends on the magnitude of the climatic forcing of the ice sheet. Only if this climatic forcing is modest, the weak or soft characteristics of the applied solid Earth structure leads the ice sheet to either stability or partial collapse. The evaluation of the climatic forcing has not been part of this project, and we relied on common approaches for parameterizing multimillennial variations of atmospheric and oceanic conditions. A more quantitative study of the Earth's possible impact on the AIS dynamics in the future or in the past will therefore require a more rigorous and physicallybased prescription of the AIS atmospheric and oceanic environment. This could be realized in a fully coupled atmosphere / ocean / ice / solid Earth system. Likewise, an assessment of the Earth structure's impact on the Antarctic post-LGM deglaciation could be improved by a more comprehensive prescription of the past climate conditions. Finally, Earth structure models need to be improved to tighten the range of plausible viscosity profiles on a global scale.

Publications

• (2013) Antarctic regional ice-mass trends 2002 to 2012 from GRACE satellite gravimetry and an improved estimate of glacial-isostatic adjustment. The Cryosphere, 7, 1499–1512
  Sasgen, I.; Konrad, H.; van den Broeke, M.; Ivins, E.; Bamber, J.; Martinec, Z.
  (See online at https://doi.org/10.5194/tc-7-1499-2013)
• (2014): ESA ITT CryoSat+ REGINA: Final Report (D6.1) for determining Regional glacial isostatic adjustment and CryoSat elevation rate corrections in Antarctica, Issue 2.2 Doc. Ref. REGINA_D6_1_issue_2.2,
  Sasgen, I. & Konrad, H. the REGINA Consortium
  
• The deformational response of a viscoelastic solid earth model coupled to a thermomechanical ice sheet model. Surv. Geophys., 35(6):1441-1458, 2014
  Konrad, H., M. Thoma, I. Sasgen, V. Klemann, D. Barbi, K. Grosfeld, and Z. Martinec
  (See online at https://doi.org/10.1007/s10712-013-9257-8)
• Potential of the solid-Earth response for limiting long-term West Antarctic Ice Sheet retreat in a warming climate. Earth Planet. Sci. Lett.
  Konrad, H., I. Sasgen, D. Pollard, and V. Klemann
  (See online at https://doi.org/10.1016/j.epsl.2015.10.008)
• Sea-level and solid-Earth feedbacks on ice-sheet dynamics (2015), Dissertation, Freie Universität Berlin
  Konrad, H.
  
• Sensitivity of grounding-line dynamics to viscoelastic deformaition of the solid-earth in an idealized szenario. Polarforschung 85 (2), 89–99, 2015 (erschienen 2016)
  Konrad, H., Sasgen, I., Klemann, V., Thoma, M., Grosfeld, K. and Martinec, Z.
  (See online at https://dx.doi.org/10.2312/polfor.2016.005)