| British
Antarctic Survey
Working at SAMS(2004)
JCR
Diaries
Autosub under Ice Diaries
Nature
news item |
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Iceland & Greenland Cruise 2004
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I was
lucky enough to be on JR106N on the James Clark Ross from August
12th - 30th 2004 as part of the SAMS contingent during my job swap.
Our nominal task was to test deep water comms for an acoustic modem
and this was a suitably short cruise to tag onto. The main reason
for the cruise however was to take arctic sea ice measurements including
the first under ice measurements using the Autosub vehicle.
We flew into Iceland on what turned out to be a week of the hottest
temperatures they have ever recorded. The population were making
the most of the good weather, with the streets and greens being
pretty busy. We didn't get much of a chance to explore outside of
the city with setting up equipment on the ship. |
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| Autosub |
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The Autosub project
is run by Southampton Oceanographic Centre (SOC). The sub' itself
can carry a range of sensors. For the under ice work it is specially
fitted with an upward looking sonar to measure sea-ice depth. There
were several missions, where its obstacle detection and avoidance
systems were used to avoid grounding or hitting icebergs within the
sea-ice. A homing beacon was also used from the ship when ice moved
over its programmed surfacing point. Ultimately it successfully performed
a 24 hour mission under the sea-ice, powered by 5000 D cells! |
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| Drilling
the Ice |
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In order to verify the data recorded
by the Autosub sonar, part of the ice under which it was traveling
was drilled through and the depth measured. Cores were also taken
to look at the structure and salinity profile of the ice. A good lookout
was kept at all times whilst working on the ice in case of Polar Bears
approaching and no work was allowed in poor visibility. |
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Ice Bears |
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We worked as far
North as 80° 40'N close to the North-East coast of Greenland
with occasional glimpses of the coast and mountains of Greenland.
On the last morning of working on the ice, after we returned from
recovering Autosub, there were fresh bear prints around where the
ship had been.
As we sailed away, a mother and two cubs were spotted swimming
after us. The ship stopped and they climbed out onto a floe just
behind us. The whole ship came out from breakfast to watch them.
They were sniffing the air of bacon with great interest.
Eventually they settled calmly on the floe, but at the first sign
of the male approaching, the mother took her cubs off and we left
the male pacing along the floe sniffing where the other bears had
been. |
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The Mooring |
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Finally on the way
back South, we got to deploy our mooring for a few hours and run
our tests in 2500m deep water. The left-hand image shows the mooring
being lifted into the water. The units you see are the acoustic
modem and an acoustic release. The anchor is the chain on the deck.
At the end of the test, a signal is sent for the release to detach
from the chain and the buoyancy brings the equipment back to the
surface - see right-hand image. It took most of an hour to travel
back to the surface from the seabed. Our tests were successful at
transferring data to and from the seabed. |
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Isafjord |
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At the end of the
cruise, we returned to Isafjord in the North of Iceland. In the
evening as we approached, we again saw large numbers of whales and
White-Beaked dolphins.
While waiting for our flight, we climbed up
to a nearby coll for views over the bay. We thought we might not
make it to Reykjavik due to the high winds. After some delay the
pilot went for it, but it was still VERY bumpy climbing out of the
fjord. |
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