Australia: The Land Where Time Began

A biography of the Australian continent 

Antarctica - Ice Flow Sensitivity of Pine Island Glacier to Geothermal Heat Flux

According to the authors1 projections of ice flow by models in a climate that is changing depend on the inputs to the model, including such factors as surface elevation, bedrock position and surface temperatures. Geothermal heat flux in the factor that is least certain. Available data sets for the area of the Pine Island Glacier, Antarctica, differ by up a factor of up to 2.5. In this paper the authors1 report their results on their evaluation of the impact on ice flow of such uncertainty by the use of sampling based on the Latin-Hypercube method. They quantified the impact of geothermal heat flux errors on the hardness of the ice, which is a thermal parameter that has critical control on the flow of ice. They then quantified the impact of the same errors on mass balance, specifically the mass flux advecting through 13 fluxgates that are distributed across the Pine Island Glacier. These results were contrasted with similar uncertainties that had been generated by errors in the ice thickness specification. Geothermal heat flux errors are indicated by the output of models to yield ice hardness uncertainties on the order of 5-7 %, with 15 % being the maximum uncertainty, though the resulting mass balance uncertainties remain below 1 %. The authors1 discuss the distribution of uncertainty and the relationship between this uncertainty and the amount of available heat at the base of the ice sheet that results from friction, viscous heating and geothermal heating. The authors1 say they also show that ice thickness errors contribute comparatively more to the uncertainty of models than geothermal heat flux errors, especially for ice streams that are flowing rapidly.

Sources & Further reading

  1. Larour, E., M. Morlighem, H. Seroussi, J. Schiermeier, and E. Rignot. "Ice Flow Sensitivity to Geothermal Heat Flux of Pine Island Glacier, Antarctica." Journal of Geophysical Research: Earth Surface 117, no. F4 (2012): F04023.
Author: M. H. Monroe
Last updated 28/07/2013
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