Large ice shelves such as the Ross Ice Shelf on the western
Antarctica coastline undergo periodic episodes of large-scale
iceberg calving. In 2000, several large pieces of the shelf broke
off and wandered around in the Ross Sea, breaking into several
smaller bergs over the next few years. Among the survivors of the
initial calving event is piece C-16. In late March 2006, C-16
worked its way northward along the coastline and plowed into the
tip of the Drygalski Ice Tongue. The collision knocked loose a
chunk from the tip of the ice tongue.
These images show iceberg C-16 and the Drygalski Ice Tongue before
and after the collision. On March 26, the table-like C-16 was
poised at the southern edge of the ice tongue, but buffered from
direct contact by a small wedge of sea ice. According to scientists
at the Space Science and Engineering Center at University of
Wisconsin, Madison, who monitor the activity, C-16 had to overcome
strong winds, known as katabatic winds, that blow down the
topographic incline from the top of David Glacier (the source of
the ice tongue) toward the sea. The katabatic winds would have been
driving the berg toward the east, but not strongly enough to
completely clear the ice tongue. The image from March 31 shows that
C-16 had clipped the tip of the ice tongue, breaking off a piece.
By April 3, both pieces of ice had swung around to the other side
of the ice tongue.
Scientists monitor ice conditions such as calving and sea ice
formation in the Ross Sea for both scientific and practical
reasons. Ice processes in polar regions are important indicators of
climate change, and the movements of sea ice and icebergs affect
shipping lanes to the research bases in Anarticas McMurdo Sound.
Satellite observations are critical for this monitoring task
because of the remoteness and extreme harshness of the
climate.
More images:
26 March 2006 high resolution image
31 Marcg 2006 high resolution image
3 April 2006 high resolution image
