期刊
GEOPHYSICAL RESEARCH LETTERS
卷 46, 期 14, 页码 8184-8193出版社
AMER GEOPHYSICAL UNION
DOI: 10.1029/2019GL083436
关键词
ice sheet modeling; radar; shear margin; Northeast Greenland Ice Stream; model validation; Greenland
资金
- NASA [NNX16AM01G, NNX15AN53H]
- NSF [1643353]
- Directorate For Geosciences
- Office of Polar Programs (OPP) [1643353] Funding Source: National Science Foundation
- NASA [800156, NNX16AM01G, 900845, NNX15AN53H] Funding Source: Federal RePORTER
Ice streams are bounded by abrupt transitions in speed called shear margins. Some shear margins are fixed by subglacial topography, but others are thought to be self-organizing, evolving by thermal feedback to ice viscosity and basal drag which govern the stress balance of ice sheets. Resistive stresses (and properties governing shear-margin formation) manifest nonuniquely at the surface, motivating the use of subsurface observations to constrain ice sheet models. In this study, we use ice-penetrating radar data to evaluate three 3-D thermomechanical models of the Northeast Greenland Ice Stream, focusing on model reproductions of ice temperature (a primary control on viscosity) and subsurface velocity. Data/model agreement indicates elevated temperatures in the Northeast Greenland Ice Stream margins, with depth-averaged temperatures between 2 degrees C and 6 degrees C warmer in the southeast margin compared to ice in streaming flow, driven by vertical heat transport rather than shear heating. This work highlights complexity in ice divergence across stagnant/streaming transitions.
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