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Sunday, November 7, 2010

"Cryo-Hydrologic Warming: A potenial mechanism for rapid thermal response of ice sheets" by Thomas Phillips, Harihar Rajaram & Konrad Steffen

Cryo-Hydrologic Warming: 
A potenial mechanism for rapid thermal response of ice sheets

by Thomas Phillips, Harihar Rajaram, and Konrad Steffen

Very interesting calculations for heat transfer from ice sheet melt water to the ice sheet via moulins:

MP, I hope I wrote that correctly.

Oh, now, I see your comment, will post below:

Mauri Pelto  Posted November 5, 2010 at 6:09 am | Permalink

The GRL paper is behind a paywall, but a presentation of this project that is more photogenic anyway Phillips et al. 2010 is available.
The press release does not examine the true impact of this potential warming of the bulk of the ice. In a paper Luthi et al. (2002) examined the temperature profile of the Jakobshavn Glacier using borehole measurements. They observed the temperature to be -5 to -10 °C at near surface depths, increasing to -20 °C by a depth of 400 m, the cold temperatures plateaued until 80 % of the distance to the ice sheet base where the temperature then warmed to near 0 °C. The velocities observed in this project indicated almost all of the motion from basal sliding and internal deformation occurred in the lowest 10-15 % of the ice stream. This is where the ice is warm. This is not unusual that basal ice is warmer and that most of the ice motion is generated here. Even on temperate glaciers most of the ice motion is generated near the glacier base due to the pressure and via basal sliding. The point is that the bulk of the ice thickness would have to be warmed considerably before it would have a signature on ice velocity and even then it is not the location where glacier and ice sheet velocity tends to be primarily derived from.

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