Articles | Volume 9, issue 1
The Cryosphere, 9, 245–253, 2015
The Cryosphere, 9, 245–253, 2015

Research article 09 Feb 2015

Research article | 09 Feb 2015

Heat sources within the Greenland Ice Sheet: dissipation, temperate paleo-firn and cryo-hydrologic warming

M. P. Lüthi1,*, C. Ryser1, L. C. Andrews2,3, G. A. Catania2,3, M. Funk1, R. L. Hawley4, M. J. Hoffman5, and T. A. Neumann6 M. P. Lüthi et al.
  • 1Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie (VAW), ETH Zurich, 8093 Zurich, Switzerland
  • 2Institute for Geophysics, The University of Texas at Austin, Austin, Texas, 78758, USA
  • 3Dept. of Geological Sciences, The University of Texas at Austin, Austin, Texas, 78713, USA
  • 4Dept. of Earth Sciences, Dartmouth College, Hanover, New Hampshire, 03755, USA
  • 5Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA
  • 6NASA Goddard Space Flight Center, Code 615, Greenbelt, Maryland, 20770, USA
  • *now at: Geographical Institute, University of Zurich, 8057 Zurich, Switzerland

Abstract. Ice temperature profiles from the Greenland Ice Sheet contain information on the deformation history, past climates and recent warming. We present full-depth temperature profiles from two drill sites on a flow line passing through Swiss Camp, West Greenland. Numerical modeling reveals that ice temperatures are considerably higher than would be expected from heat diffusion and dissipation alone. The possible causes for this extra heat are evaluated using a Lagrangian heat flow model. The model results reveal that the observations can be explained with a combination of different processes: enhanced dissipation (strain heating) in ice-age ice, temperate paleo-firn, and cryo-hydrologic warming in deep crevasses.

Short summary
We analyze the thermal structure of the Greenland Ice Sheet with a heat flow model. New borehole measurements indicate that more heat is stored within the ice than would be expected from heat diffusion alone. We conclude that temperate paleo-firn and cyro-hydrologic warming are essential processes that explain the measurements.