The next CIRFA seminar with a special focus on icebergs will be given by Trygve Kvåle Løken (UiO), Laust Færch (CIRFA/UiT), Nick Hughues (Met Norway/CIRFA) and Thomas Kræmer (CIRFA/UiT).

WHEN: 20 May 2021, 14:00-15:00.
WHERE: Click here to join the meeting

We look forward to seeing you!

Thomas, Andrea and Malin

Trygve Kvåle Løken (UiO): Iceberg stability during towing in a wave field (20 mins)

Photo: Trygve Kvåle Løken, and 66North / Unsplash

Due to their large mass and small aspect ratio, icebergs poses a threat to boats and offshore structures. Small icebergs and bergy bits can cause harm to platform hulls and are more difficult to discover remotely. As icebergs are dynamic mediums, the study of icebergs in relation to safe human operations requires the rigorous analysis of the ice-ocean interaction, in particular with waves and currents. The interaction between waves and icebergs is critical for the safety of human operations as the wave field influences iceberg drift. 

In this talk, I will present iceberg towing experiments carried out on Svalbard in September 2020. The icebergs were small, in the order of 100 tons. Iceberg stability was analyzed from GPS tracks and inertial motion unit data. The towline tension as well as the boat motion relative to the iceberg was measured. Different scenarios were investigated by changing the towing strategy with regards to towing speed, direction (straight or curved trajectory) and acceleration. Large amplitude roll oscillations with period of approximately 30 s were observed immediately after the load dropped and the iceberg returned to a stable static position. In two of the cases, the iceberg flipped over partly or entirely after some towing time. From the load cell, we observed oscillations in the system with periods of approximately 6 s, which were attributed to the rope elastic properties and the iceberg response. The sea state, i.e. ocean current and wave height, was monitored in the vicinity of the experiment with an ADCP and a small wave buoy. The load oscillations increased when the towing direction was against the waves as opposed to perpendicular to the waves.

Laust Færch, Nick Hughes and Thomas Kræmer: Latest iceberg research in CIRFA: Results and applications (20 mins)

Laust Færch (photo by Bodil Færch) and Nick Hughes (photo: private).

The expected increase in maritime traffic in the high north necessitate improved and reliable methods for detecting icebergs accurately and over vast areas. 

In an operational context, icebergs are often mapped using Synthetic Aperture Radar (SAR) images, such as those delivered by the European Sentinel-1 satellites, that operate independent on sunlight and weather conditions.

In this project, we will develop new methods for mapping iceberg distribution and occurrences in the Barents Sea using satellite imagery, and investigate capabilities and limitations of iceberg detection algorithms, both existing and new.