USGS Groundwater Information: Hydrogeophysics Branch
Publications > Briggs and others, 2014
Martin A. Briggs1, Michelle A. Walvoord2, Jeffrey M. McKenzie3, Clifford I. Voss4, Frederick D. Day-Lewis1, and John W. Lane1
1Office of Groundwater, Branch of Geophysics, U.S. Geological Survey, Storrs, Connecticut, USA
2National Research Program, Central Branch, U.S. Geological Survey, Lakewood, Colorado, USA
3Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec, Canada
4National Research Program, U.S. Geological Survey, Menlo Park, California, USA
Figure 1. (a) The Twelvemile Lake site, south of the Yukon River in central Alaska. (b) Discrete bands and clumps of predominantly willow shrub vegetation are evident within the dried margin of Twelvemile Lake, bounded by contiguous spruce and deciduous forest that is generally underlain by thick (>100 m) permafrost. (c) Cross section of electrical resistivity along the profile collected in late summer 2012 shown in (b). Discrete resistive zones in the subsurface indicate permafrost aggregation that was confirmed with physical frost probing and other methods.
Widespread lake shrinkage in cold regions has been linked to climate warming and permafrost thaw. Permafrost aggradation, however, has been observed within the margins of recently receded lakes, in seeming contradiction of climate warming. Here permafrost aggradation dynamics are examined at Twelvemile Lake, a retreating lake in interior Alaska. Observations reveal patches of recently formed permafrost within the dried lake margin, colocated with discrete bands of willow shrub. We test ecological succession, which alters shading, infiltration, and heat transport, as the driver of aggradation using numerical simulation of variably saturated groundwater flow and heat transport with phase change (i.e., freeze-thaw). Simulations support permafrost development under current climatic conditions, but only when net effects of vegetation on soil conditions are incorporated, thus pointing to the role of ecological succession. Furthermore, model results indicate that permafrost aggradation is transitory with further climate warming, as new permafrost thaws within seven decades.
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USGS Press Release, March 2014: New Permafrost... But is it Permanent?
Alaska Public Media: Newly Forming Permafrost May Not Survive Century's End
Science 2.0, June 2014: New Permafrost Is Forming Around Arctic Lakes
Radio Canada, June 2014: Un nouveau pergélisol se forme en Arctique
LiveScience, March 2014: Despite Warming, Ground Refreezes at Alaska's Shrinking Lakes
Nature Research Highlights - Climate Change, February 2014: Permafrost grows thanks to plants
Climate Wire, March 2014: What is driving shrinking of Arctic lakes? Scientists look to the permafrost
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Final copy as submitted to Geophysical Research Letters for publication as: Briggs, M.A., Walvoord, M.A., McKenzie, J.M., Voss, C.I., Day-Lewis, F.D., and Lane, J.W., 2014, New permafrost is forming around shrinking Arctic lakes, but will it last?: Geophysical Research Letters, v. 41, doi: 10.1002/2014GL059251