SAMS news room

Defying the perils of the Arctic, SATICE survives a winter battering

In defiance of a long, dark, frozen, Arctic winter, data from a spar buoy deployed in the Arctic Ocean last August is being received and processed by the Scottish Association for Marine Science (SAMS) and the Consejo Superior de Investigaciones Científicas (CSIC), as part of the first, continuous and ground-breaking GPS positioning experiment on Arctic Ocean sea ice and circulation.

The buoy, known as SATICE, is beaming home the longest-running, ultra-high precision GPS data-set ever collected from the Arctic Ocean, telling tales about the sea ice on which it is sitting and the ocean circulation around it.

SATICE and other equipment left the west coast of Scotland mid June 2012, travelled by sea to the port of Incheon, Korea. From there it was taken on board the Korean Polar Research Institute’s icebreaker RV Araon, arriving at its Arctic Ocean destination two months later at 83N, 178W, 1000 nautical miles due north of the Bering Strait.

Designed and engineered at SAMS in partnership with CSIC, SATICE is purpose-built for monitoring ice and ocean parameters, which is crucial for improving our understanding of the key thermodynamic and dynamic processes that drive Arctic climate change.

It is 5.7m tall with 4m of that length below the sea ice. It has three arms, each 1.5m long and together with the vertical upright they host a number of platforms including the GPS and Iridium antennae, a snow depth sensor, a digital camera and sensors measuring conductivity and sea levels, as well as an automatic weather station. As the buoy drifts on the sea ice, each platform is continuously collecting data; recording geophysical measurements on sea ice drift, freeboard, weather, ice mass balance, and sea levels.

SAMS engineer Shane Rodwell said: "I think what's important to note is just how hard it is to do this stuff: to get it there in the first place, to keep it all running, but mostly to have the luck to survive a winter frozen into the harsh Arctic Ocean."

SATICE has an impressive list of scientific goals. It is designed to gauge spatio-temporal variations of ocean tides in the Arctic Ocean, sea-ice freeboard heights, ice thickness, ice mass balance, ocean dynamic topography, ocean circulation, freshwater storage, and to provide calibration and validation of ESA's Cryosat-2 measurements.

All these estimates will be used to improve coupled ice-ocean-atmospheric models and Arctic Ocean tide models using in situ, high-precision GPS observations of sea-ice motions, satellite-based radar and lidar sea-ice altimetry, and satellite gravity.

Mr Rodwell explains that on an engineering level these autonomous platforms bring out a level of spatio-temporal detail that has never been seen before, especially in the vertical axis. "These high-resolution data allow us to address new polar science questions and challenge our present understanding of both sea ice dynamics and Arctic oceanography."

The on-board digital camera was installed for engineering diagnostic purposes. It has been taking four photographs a day since the buoy’s deployment, which have been turned into a dramatic time lapse.

"Given the dynamics of sea ice it is very rare that we ever have equipment survive a winter. The fact we have pictures is even better" said Mr Rodwell.          

Apart from eleven weeks of total darkness, the photos show the severity of the environment, from blinding sunlight to frozen blue snow and ice. In the background of the photos there are on the sea ice two yellow boxes of other technological gadgetry and wizardry, deployed at the same time as SATICE. As the days pass, movement of the ice causes tremendous pressure and an ice-ridge has appeared.

"There was another instrument there but it stopped responding a few months ago. It was deployed right where that ridge has appeared and these pictures pretty much confirm what happened to it: eaten by the sea ice."

As the Arctic emerges from days of perpetual darkness, the ghostly images now being received evoke the ice-ridden rigging of Longfellow’s Hesperus. How much longer the spar buoy will survive depends as much on the weather and the hungry ice as it does on polar bears, which aren’t keen on technology.

SATICE involves six partner institutes from six European countries.

Funder: European Science Foundation

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