Azipod® propulsion enables key Arctic climate research expedition

Azipod® propulsion enables key Arctic climate research expedition

Proving that a vessel of modest power and proportions could navigate the extremes of the Earth, the Norwegian Coast Guard’s KV Svalbard carried an international team of climate researchers to the North Pole in August of 2019, aided by the operational capabilities of ABB Azipod® propulsion.

The research expedition was led by the Nansen Environmental and Remote Sensing Center (NERSC), with funding from the Research Council of Norway and the EU HORIZON 2020 program. The mission’s main purpose was to improve collection of on-site observations in the central Arctic Ocean. “Satellites provide surface measurements that are excellent for monitoring the changes in the sea ice cover. But in order to understand the large changes taking place in the Arctic, we need better information on how warm and dynamic the ocean is under the ice,” says Hanne Sagen, research leader at NERSC.

  • Commanding officer Geir Martin Leinebø and Andreas Kjøl, Norwegian Coast Guard, at the North Pole. Photo: Norwegian Coast Guard
  • Commanding officer Geir-Magne Leinebø and expedition leader CAATEX Dr. Hanne Sagen at the North Pole. Photo: Norwegian Coast Administration

“It is urgent to improve ocean observational capacity in Arctic,” Sagen emphasizes. “The data collected will be used to check whether climate models are able to reproduce the observed changes, which will in turn be used to improve climate projections. Better climate projections will help us to plan and adapt to climate change, and that will impact millions of lives around the globe.”

KV Svalbard’s task was to help deploy a system of drifting ice buoys and seabed-anchored underwater moorings equipped with sound sources and receivers. “The Norwegian Coast Guard has historically partnered with the Coastal Administration on their ice-going projects,” says senior engineer Andreas Kjøl of the Norwegian Coastal Administration. “Navigating in the central Arctic requires strategic route planning using sea ice information from a large number of satellites, and that is where our expertise in ice analysis becomes useful.”

Mission accomplished

KV Svalbard is an icebreaking offshore patrol vessel designed for navigation in one meter of multi-year ice. The 104-meter vessel features two 5MW Azipod® propulsion units. The goal of the expedition, which required more than one year of detailed planning, was to reach as far north as possible. Kjøl notes that the team was particularly pleased to have made it the entire way to the North Pole.

“The combination of thorough preparation, vessel performance and crew experience was the key to success,” he confirms. Ice status was monitored for six months prior to the expedition, and a route to the east of Svalbard was selected for lighter ice coverage, though still challenging for a vessel the size and power of KV Svalbard. “Keep in mind that this is the region with the most extreme ice conditions on the planet. The success of the mission was a major accomplishment given the physical and environmental parameters.”

Though KV Svalbard has operated for years in the Arctic, the team expected to encounter challenges with thick multiyear ice in the higher latitudes. “We were even prepared to freeze in due to waiting, but this never happened,” Kjøl says.

Azipod® propulsion performed admirably

Deploying each of the moorings in the demanding Arctic environment required three days; one to locate the desired position for the mooring, one to deploy the mooring, and a third to deploy and position a network of transponders – communication devices that receive and send signals – around the mooring. The deployment operation demanded both skillful planning and execution, and a nimble ship. The maneuverability provided by Azipod® propulsion was a big advantage, Kjøl reports, not just for general navigation, but in situations requiring more finesse. “It gave us more options, like backing in to the ice to safely deploy equipment and make camp.”

KV Svalbard employed several maneuvers to assist forward propulsion during the mission. “We could induce heeling with pod propulsion, what we call the ‘duck walk’. The rocking motion gives the ship more space in the ice. The helmsmen are very fond of the Azipod® units because of options like this that allow them to keep up momentum.”

The voyage proved to be a newsmaker within the realm of ice navigation. “We were the first Norwegian vessel to reach the North Pole, and this sends a signal to the icebreaker community that independent polar navigation is possible,” says Kjøl. “We also proved that Azipod® propulsion can enable smaller vessels to handle multiyear ice.”

Keeping watch over the water

Moorings deployed during the KV Svalbard Arctic mission are part of a basin-wide acoustic system to measure mean ocean temperature – average temperature during a pre-defined time period. Each mooring carries acoustic and oceanographic instruments mounted on four kilometer-long cables kept vertical by floatation elements and tethered to the sea floor by anchors. The system has two low frequency sources, one positioned in the Nansen Basin and one in the Beaufort Sea, each emitting signals received by hydrophone arrays on moorings hundreds of kilometers away. “Sound waves travel faster in warmer water than cold,” Sagen explains. “A temperature increase of one degree increases the speed of sound by four meters per second. Measuring the varying speed of sound waves allows us to obtain accurate mean ocean temperature data.”

Sagen tells that similar measurements were made in 1994 and 1999, with a 0.5 degree increase in temperature observed over those five years. “It has been 20 years since the last measurements, and this has been perhaps the period with the biggest environmental changes in modern history.” The acoustic system allows ocean temperatures to be measured over a 2,500 km range in just about half an hour. “Using a research vessel to obtain traditional oceanographic profiles across the same section, it would take weeks to collect the same data. The acoustic system is designed to give instantaneous and reliable measurements of the mean ocean temperature with an accuracy of 10-50 millidegrees for the entire Arctic Basin every 36 hours for a full year.”

Once deployed, the moorings are covered by sea ice, making it impossible for them to transfer information to satellites. The solution is to store data in each unit until recovery, scheduled for autumn 2020.

Right to be there

Kjøl acknowledges concerns over more vessels sailing further north, and more often. “This is a relatively new phenomenon in the High North, and there are fears that more frequent passages may have a permanent impact on the ice structure,” he says. Nonetheless, he believes the benefits of research expeditions far outweigh negative consequences. “On this mission we acquired knowledge that is vital for the informed management of the polar regions. This helps us not only to understand climate change, but informs decisions on how to manage polar environments responsibly.”

All experience gained during planning and execution of the mission is contributed to the international search and rescue exercise project SARex Svalbard, he tells. “The stakeholders are dedicated to sharing results to strengthen our common knowledge base, and to help ship operators be better prepared to ensure improved safety for Arctic shipping.”

Figure 1. The navigation of the ship required extensive analysis of high resolution Earth Observation data from several providers and satellites e.g. Synthetic Aperture Radar data from Sentinel 1, Radarsat 2, and Cosmo Skymed. AMSR2 passive microwave data were used to observe the ice concentration (color coded). The optical images (e.g. Terra Modis) were, under cloud free conditions, used as support to detect open leads and ridges. Automatic Identification System (AIS) was used to observe the details of changes in ice drift, both via satellites and buoys deployed around the ship. The photo shows the KV Svalbard with the deployment of ice tethered profiler (ITP) buoy at the North Pole in the foreground. The ITP autonomously measures oceanographic profiles while it drift with the ice. These data are sent back to scientists at Woods Hole Oceanographic Institution in near real time via IRIDIUM. (Mosaic: A. Kjøl. Photo: H. Sagen)
Figure 1. The navigation of the ship required extensive analysis of high resolution Earth Observation data from several providers and satellites e.g. Synthetic Aperture Radar data from Sentinel 1, Radarsat 2, and Cosmo Skymed. AMSR2 passive microwave data were used to observe the ice concentration (color coded). The optical images (e.g. Terra Modis) were, under cloud free conditions, used as support to detect open leads and ridges. Automatic Identification System (AIS) was used to observe the details of changes in ice drift, both via satellites and buoys deployed around the ship. The photo shows the KV Svalbard with the deployment of ice tethered profiler (ITP) buoy at the North Pole in the foreground. The ITP autonomously measures oceanographic profiles while it drift with the ice. These data are sent back to scientists at Woods Hole Oceanographic Institution in near real time via IRIDIUM. (Mosaic: A. Kjøl. Photo: H. Sagen)
Figure 2. The geometry of the 2019–2020 Coordinated Arctic Acoustic Thermometry Experiment (CAATEX) and the Integrated Arctic Observation System (INTAROS) experiments. The acoustic moorings at SIO1 and NERSC1 carry both source and receivers. There are four vertical receiving arrays: SIO2, SIO3, NERSC2, and NERSC3. The mooring at NERSC4 (green) has conventional oceanographic instrumentation to measure temperature, salinity, and currents. The SIO moorings were deployed by Scripps Institution of Oceanography using the US Coast Guard ice breaker Healy. The sea-ice concentration on 31 October 2019 is from the Advanced Microwave Scanning Radiometer 2 (AMSR2) dataset provided by the University of Bremen (Spreen et al., 2008). (Source: https://seaice.uni-bremen.de/sea-ice-concentration/)
Figure 2. The geometry of the 2019–2020 Coordinated Arctic Acoustic Thermometry Experiment (CAATEX) and the Integrated Arctic Observation System (INTAROS) experiments. The acoustic moorings at SIO1 and NERSC1 carry both source and receivers. There are four vertical receiving arrays: SIO2, SIO3, NERSC2, and NERSC3. The mooring at NERSC4 (green) has conventional oceanographic instrumentation to measure temperature, salinity, and currents. The SIO moorings were deployed by Scripps Institution of Oceanography using the US Coast Guard ice breaker Healy. The sea-ice concentration on 31 October 2019 is from the Advanced Microwave Scanning Radiometer 2 (AMSR2) dataset provided by the University of Bremen (Spreen et al., 2008). (Source: https://seaice.uni-bremen.de/sea-ice-concentration/)

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