Climate Dynamics

, Volume 38, Issue 5–6, pp 1249–1262

Interactions between stationary waves and ice sheets: linear versus nonlinear atmospheric response

  • Johan Liakka
  • Johan Nilsson
  • Marcus Löfverström
Article

DOI: 10.1007/s00382-011-1004-6

Cite this article as:
Liakka, J., Nilsson, J. & Löfverström, M. Clim Dyn (2012) 38: 1249. doi:10.1007/s00382-011-1004-6

Abstract

This study examines the mutual interaction between topographically-forced atmospheric stationary waves and continental-scale ice sheets using a thermomechanical ice-sheet model coupled to a linear as well as a fully-nonlinear dry atmospheric primitive equation model. The focus is on how the stationary-wave induced ablation feeds back on the ice sheet. Simulations are conducted in which an embryonal ice mass, on an idealised “North American” continent, evolves to an equilibrium ice sheet. Under the coupling to the linear atmospheric model, the equilibrium ice sheet is primarily controlled by the ratio between the wavelength of the stationary waves and the zonal continental extent. When this ratio is near two, the ice sheet has its center of mass shifted far eastward and its shape is broadly reminiscent of the Laurentide ice sheet at LGM. For wavelengths comparable to the continental extent, however, the ice margin extends far equatorward on the central continent but is displaced poleward near the eastern coast. Remarkably, the coupling to the nonlinear atmospheric model yields equilibrium ice sheets that are virtually identical to the ones obtained in uncoupled simulations, i.e. a symmetric ice sheet with a zonal southern margin. Thus, the degree of linearity of the atmospheric response should control to what extent topographically-forced stationary waves can reorganise the structure of ice sheets. If the stationary-wave response is linear, the present results suggest that spatial reconstructions of past ice sheets can provide some information on the zonal-mean atmospheric circulation that prevailed.

Keywords

Stationary wave Coupled atmosphere-ice sheet modeling Stationary wave-ice sheet interactions Flow-induced ablation Nonlinear topographic wave response Laurentide ice sheet 

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Johan Liakka
    • 1
  • Johan Nilsson
    • 1
  • Marcus Löfverström
    • 1
  1. 1.Department of MeteorologyStockholm UniversityStockholmSweden

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