Quarterdeck 4.1
Conclusion
You mean Santa's at the North Pole?!
by Thomas Whitworth III
[...Continued from Part 1]
The most prominent front, and the first to be noticed, was dubbed the
Antarctic Convergence by Sir George Deacon in the 1930s, but is usually
called the Polar Front these days. By the late 1970s, the Subantarctic front
to the north was recognized as circum-polar. More recently, Texas A&M
oceanography graduate Alex Orsi showed that a third front, the southern
ACC front, is also a ubiquitous feature of the current. One of the goals
of our cruise on the Knorr was to pinpoint the location of the fronts more
precisely in this data-sparse region.
We confirmed that the southernmost front of the ACC turns northward after
squeezing through a deep gap south of the Kerguelen Plateau near 85°E.
Sophisticated tracer information was hardly required for this discovery
because a line of nature's own tracers (icebergs) streamed continuously
toward the north here, and then turned toward the east.
Our eastward transit between the end of our first line at 85°E and
the beginning of the second one at 110°E was lengthened by more than
a day when the Knorr was forced to retrace her track and head west and then
north to avoid the dead end formed by the convergence of drifting ice to
the north and permanent ice to the south.
There she blows!
Most of the science party was able to relax a bit during the three-hour
transit from one station to the next, but four NOAA whale-watchers pulled
the swing shift-they rested during stations, and manned the flying bridge
when underway. Their job seems enviable in the tropics, but its appeal diminished
considerably when several layers of survival gear were required to withstand
the cold and wind.
They watched for birds, whales, and other wildlife any time the ship was
underway during daylight. On the southern reaches of our cruise track, not
only was it cold, but night lasted only four hours or so. Not even fog provided
a break for the NOAA team-they were pressed into service as look-outs to
watch for growlers, VW-sized bits of broken icebergs that barely break the
surface but could easily break the ship.
Despite a reputation for teeming wildlife, these Antarctic waters were surprisingly
barren. For several days, there were not even any birds in sight.
A highlight of the cruise was the pair of humpback whales that cavorted
close to the ship for several hours during a Christmas Day station. The
performance was dizzying; hoards of shutter-clicking humans raced clockwise,
and then counterclockwise around the main deck frenetically composing shots
of whales, sky, bulkheads and other scientists' backs.
On New Year's Day, we made our second excursion to the edge of the icepack,
this time almost to 65°S. Clear skies and calm seas enticed photographic
gear topside, once again proliferating the idea that Antarctic cruises are
blessed with perfect weather. The truth is that half of everyone's photographs
are taken on the same two good days.
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Oceanography, Texas A&M University
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Updated May 27, 1996