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magazine / so07
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September/October 2007 issue |
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| IMAGE: CANADIAN SPACE AGENCY |
Dynamic Davis
Waves, weather and ice create an ever-changing
seascape at the Arctic Circle
By Elizabeth Shilts
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| MAP AND IMAGE COLOURIZATION: STEVEN FICK/CANADIAN GEOGRAPHIC |
Alow-pressure weather system churns the ocean waters in
Davis Strait, east of Baffin Island in Nunavut, producing
a spiral of wind-roughened waves on the
fringe of the mid-season ice pack in this colourized version of a
Radarsat image of the eastern Arctic.
Freeze-up begins in the fall and wind and waves mould and
manipulate the sea ice through the winter. The dark shear zone
, which forms first and fastens to the shore, is relatively
smooth and static. The rest of the ice pack is dynamic,
cracking, shifting, moving throughout the season.
Most of the sea ice measures between 70 and 120 centimetres
thick, but bright white chunks of multi-year ice, which migrate
down from the High Arctic and become entrained in the pack,
are typically several metres thick and pose a deadly threat to any
ship or icebreaker that encounters them. The thinnest and newest
ice reaches its filamentous fingers into the sea - a function of
shifting wave and wind action.
The currents in Davis Strait act as a natural conveyor belt
for icebergs that calve off glaciers along the west coast of
Greenland. The bergs travel north into Baffin Bay, then circle
back south, where they get trapped in this winter sea ice on
Baffin's eastern shores. When melting begins in April, the
icebergs are set free and float south past Newfoundland and
toward a watery grave in the Atlantic Ocean.
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