Aug. 30, 2013 Two days on an ice floe may not seem like paradise, but for a team of scientists on the multinational 2013 Oden Arctic Technology Research Cruise, it was the achievement of an important research goal.
"They surveyed the ice floe quite thoroughly," said Raed Lubbad, cruise director and an associate professor at the Norwegian University of Science and Technology's (NTNU) centre for Sustainable Arctic Marine and Coastal Technology (SAMCoT), which is coordinating the cruise. "They took many cores and measured different mechanical properties of the sea ice."
The Swedish icebreaker Oden left Longyearbyen, Svalbard on 19 August and will return on 2 September. The two-week cruise has been designed to allow the 28 ice engineers and scientists onboard to measure and quantify different aspects of sea ice, icebergs and their interaction with the ship.
Five marine mammal researchers are also aboard the vessel, where they have been conducting acoustic research and combining conventional marine mammal observations with more high-tech approaches. To date, the marine mammal group has seen 159 animals, including bowhead whales to harp seals and white beaked dolphins.
Ice station ho! For the Oden ice engineers, the chance to spend two days examining a big sea ice floe is an important opportunity to collect vital information about how strong and thick the ice is, how deep and consolidated the pressure ridges formed in the ice are, and how the ice interacts with a big piece of metal -- like the bow of the icebreaker Oden.
This kind of information will become more and more important as global warming results in an ice-free Arctic Ocean in the summer, and shipping traffic increases.
According to an estimate made by Det Norske Veritas (DNV), an international risk management company based in Norway, as many as 850 transit trips could be made across the Arctic Ocean by 2050.
Lubbad reported via email that while one team conducted ice thickness measurements, another team spent time studying an ice ridge.
"They drilled through it at different cross-sections and established a good profile of the ridge," he said. "We have also used an EM antenna and scanned the thickness of the ice floe. The ice topography and the relative distances between the ship and all the measurement points on the ice were measured using the Total Station and a GPS."
ROVs and ice ramming The ship also has a remotely piloted aircraft system (RPAS), which they used to document the layout of the ridges on the ice floe.
In the end, the researchers completed the ice station with a bone-jarring ridge ramming test, where Oden made her way through a 12m thick ice ridge.
The icebreaker travelled a pre-surveyed 1000m ramming path, and the vessel itself was monitored during the ramming test.
Researchers also deployed a sound recorder close to the ice floe before they began their work. The sound recorder collected while scientists worked on the ice station and during the ridge ramming experiment.
"These data are useful to measure the level of noise an icebreaking operation produces and how could this influence the environment around it," Lubbad said. He also noted that the sound recorder was retrieved successfully right after the ramming test was finished -- no mean feat in the swirling soup of broken up ice.
Wind and weather
On Tuesday, 27 August, the Oden arrived at the location of the last of four instrument-laden moorings that the researchers deployed last year. These underwater moorings have been busily collecting ice and ocean current data for the last year, and retrieving them is one of Oden's most important tasks on this cruise.
While this may seem like an easy assignment, it poses many challenges, as the Oden cruise discovered on the 27th.
"We arrived at the location of our fourth (and last) mooring in the morning," Lubbad wrote. "The position of the mooring was located, but it was too windy and we had quite some ice with high drift speed in the area."
Instead, the Oden headed northwest to look for icebergs that would be suitable for the team's iceberg remote station, in which an iceberg is measured top to bottom, and a remote tracking sensor is installed on the berg to measure its movements for the next several months.
But once the boat arrived at its target location, "we unfortunately had bad visibility which prohibited us from using the helicopter to establish our Iceberg remote station and to deploy ITDs (Ice Tracker Drifters) on ice," Lubbad said in his email. "We thought of performing ice management tests in that area but the ice conditions in combination with bad visibility did not allow this either."
In the end, the researchers were able to take advantage of one of the features of the area where they were -- the shallow water depth. The group is mapping the seabed in shallow areas to look for and better understand ice gouging and scouring from icebergs.
"Therefore we decided to use the opportunity and map the seabed in the area thoroughly -- which we did," he said.
Mooring success The Oden returned to the last mooring location on Wednesday, 28 August, and was finally able to retrieve the mooring, with all of its instruments.
Cruise director Lubbad was very happy about this result.
" We had a very good start today," he wrote in his email about the event. "Right after breakfast we managed to retrieve our last mooring successfully with its entire instrument intact. This means that in this cruise we actually managed to retrieve all four moorings where three of them were complete and intact."
Earlier in the cruise, the first mooring the ship located and retrieved was without its package of instruments -- probably ripped off the mooring by a big passing iceberg.
Lubbad reported that the researchers were also able to successfully redeploy all four new moorings with instrument packages, so they can continue their vital work of collecting data over the next year.
A multinational group The cruise participants come from NTNU, the University Centre in Svalbard (UNIS), TU-Delft in the Netherlands, Saint Petersburg State University, the Technical University of Catalonia BarcelonaTech (UPC) in Spain, the University of Alaska-Fairbanks, the University of Delaware, the Norwegian oil company Statoil, Maritime Robotics, ASL Environmental Sciences in Canada, Marine Observers in Denmark, and the Ship Modelling and Simulation Centre AS in Norway.
The cruise was made possible in part by a memorandum of understanding between NTNU and the Swedish Polar Research Secretariat, and is being conducted with support from Statoil and in collaboration with the Swedish Maritime Administration, which owns Oden.
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The above story is based on materials provided by The Norwegian University of Science and Technology (NTNU), via AlphaGalileo.
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