Basic HTML Version
55
SAMC
o
T
• ANNUAL REPORT 2013
“Then, when we found some ridges, it became apparent
that going through the consolidated layer to reach the
ice rubble was going to be a lot more laborious than we
first thought,” Polojärvi explains.
Fortunately, the expedition included hardy and deter-
mined UNIS master’s students from the course AT-211.
They were a valuable resource to the ongoing research
and provided great assistance. “Here the UNIS students
who were on the cruise were a lot of help. It should be
also mentioned that the same students did the profil-
ing of the ridges we studied, which of course helped and
saved a lot of our time,” Polojärvi said.
Polojärvi explains that one of the test sites was in the
middle of an active rubble field, which turned out to be
an advantage. “The ice movement enabled us to collect
freeze bond samples that had very recently surfaced
and were probably formed underwater. Walking around
this rubble field was an exciting experience since at
times you could hear, feel and even see the ice moving.”
Much more than ridges
While Polojärvi and his group concentrated on digging
into the ice ridges the rest of the researchers and
students were divided into different groups each with
a specific research task. The beam testing group
performed cantilever beam and Sodhi-beam testing; the
ice ridge group performed ridge profiling with 2’’ augers
and then took cores for TDS testing; the indentation
group operated a huge hydraulic indenter; the kompis
group tested the compression strength of ice cores
for level ice and for ridges; the oceanography group
measured currents and salinity-temperature profiles of
water. In addition they also made a comparison of turbu-
lent kinetic energy measured by ADV and ADCP. Several
Ice Trackers were deployed at the end of the cruise to
track ice drift.
More than `just´ field work
After the cruise Polojärvi and Tuhkuri spent five days
in a cold room at UNIS making thin sections from the
samples and photographing them for later analysis.
This work turned out to be quite intensive. They spent
long days in a small room that turned out to be colder
than the cold temperatures experienced during the
cruise. The research is being continued at Aalto, with
the analysis of the thin section photographs.
The expectations of SAMCoT lead researchers and
our industry and research partners are in line with
Polojärvi´s conclusion regarding this experience. “I
think the fieldwork on the cruise taught me a lot on many
topics and issues that are related to my work on numeri-
cal modelling: not only directly due to the samples we
got from the field, but also indirectly through seeing how
ice rubble in the field looks like and how the field work is
performed,” he said.
A year later this SAMCoT postdoc still smiles when he
remembers everything he experienced and learned
during the LANCE 2013 research expedition. “In all
honesty, seeing polar bears, walruses and seals did not
make me any less happy,” he said.
Cutting blocks from a ridge during the LANCE cruise.
Photo: Jukka Tuhkuri