Spatiotemporal Patterns of Permafrost Destabilization Following Snow Fence Installation at Barrow, A

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Spatiotemporal Patterns of Permafrost
Destabilization Following Snow Fence Installation
at Barrow, Alaska
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Kenneth M. Hinkel John K. Hurd, Jr. Department
of Geography, University of Cincinnati
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4 m high and extends approximately 2.2 km
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Browerville
Barrow
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0
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Looking north May 1999
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5
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Looking north, showing fence scour zone and drift
on left
May 1999
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View along drift crest in August 1999 showing
ponds caused by thaw subsidence
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7
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August 2004
fragmented surface organic mat, 2004
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Five-year objectives
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• Monitor and model the thermal impact of the
  drift on the upper soil (0-50 cm) region
• Monitor thaw subsidence beneath drift
• Measure drift impact on soil moisture
• Determine impact of drift on vegetation and
  soil

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Drift study plot showing location where soil
temperatures collected since Aug 1999 at 5, 30
and 50 cm. Also, soil and vegetation plots
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Control study plot showing location where soil
temperatures collected
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Snow thickness and thaw depth along middle drift
transect Note shallow thaw beneath the snow
drift and enhanced thaw in the fence and lee
scour zones
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35 cm
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Snow thickness along middle drift transect,
showing 60 greater volume of snow in 2001 with
no fence scour zone. Logger locations shown in
green
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a
b
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Looking south, mid-August 2001
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2000-01 avg snow year (32 cm) but several
strong blizzards
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Aerial view of study site looking north,
mid-August 2001
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a
b
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Conclusions
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• Drift dimensions show considerable interannual
  variation
• Soil thaw beneath drift crest typically delayed
  4-8 weeks
• Winter soil temperatures beneath the drift is
  2-14?C warmer than Control, and demonstrate
  strong attenuation and lag
• The mean soil temperature near the top of
  permafrost beneath drifts increased 2-5?C over
  the 6-year period, and permafrost is degrading.
  The effect is widespread and progressive over
  time.
• Preexisting ponds have become larger and deeper
  over time new ponds have developed causing
  differential ground subsidence

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This research was supported by grants from the
National Science Foundation to KMH (OPP-9529783,
9732051, and 0094769), although opinions,
findings, conclusions, or recommendations are
those of the authors and do not necessarily
reflect the views of the NSF. We are grateful to
the Ukpeagvik Inupiat Corporation for access to
the Barrow Environmental Observatory, and the
Barrow Arctic Science Consortium for
administrative and logistic assistance.