ThinTec instrument is hitchhiking on thin ice

Deployment of the ThinTec instrument in Ramfjorden with the ice edge at the innermost part of the fjord (light grey). Sea ice on the fjord appears white and open water appears black. Image: Paul A Dodd (portrait) and ESA/Copernicus.

What is young and thin ice doing, and where is it moving right when it forms? Malin Johansson send her pink drifter called ThinTec for a hitchhike on the ice to watch it grow, track its movements, and send its measurements in real time to Malin`s computer via its GPS antenna.

Preparation work included analyzing the latest satellite image. Photo: Malin Johansson

Of all sea ice types that can be observed with the help of satellites, freshly growing ice that is only a few cm thick yet is most difficult to observe via satellite images and to accurately monitor automatically. Thin ice is significantly underrepresented in sea ice drift estimates due to its limited thickness, and the data that ThinTec is collecting will help to understand its movements better.

ThinTec is the first prototype for this task carrying only a GPS onboard, and temperature sensors will be installed in the next version to measure the water temperature and the sea ice thickness. Malin tested the tracker in Ramfjorden near Tromsø on the evening of May 1^st where it was deployed on 4cm thick ice that was attached to the shore (so-called landfast ice). The instrument stayed on the ice until the afternoon of May 4^th, at which point it broke loose and drifted towards the shore where Malin collected it. The ice thickness at the front was then 10-15 cm thick and had retreated further into the fjord.

Arriving at the ice edge in Ramfjorden. Photo: Malin Johansson

Sentinel-2 image from 2nd of May at 12:40 Norwegian time. The green dots show the track of the instrument, from the ice edge until it landed on the island Holman on May 4th. Image source: ESA/Copernicus.

Malin Johansson is a researcher at the department of Science and Technology at UiT and specializes on investigating thin ice and oil films at the water surface. The fieldwork was part of the ThinTec – Thin Ice Measurement Technology project funded by the Flagship Arctic Ocean and is a part of the research in CIRFA. Within ThinTec, Malin and her colleagues at Met.no and UNIS are developing an open-source technology to measure thin ice growth in near-real time and subsequent drift to support automatic sea ice classification and mapping.

Young and thin ice at the transition zone between water and ice, the so-called marginal ice zone, is also crucially important for marine life. Especially algae, birds and marine mammals are part of a unique ecosystem between a belt of ice floes with patches of open water in between them. Leanr more about the ice edge on the website of the Norwegian Polar Institute (NPI), one of CIRFA`s partners.