Sea ice is constantly being pushed and pulled by winds and ocean currents, drifting and deforming. A new satellite-based product developed at the Nansen Center gives researchers a way to follow that motion and deformation from days to months, benefitting both climate research and Arctic operations, such as the currently ongoing research cruise for the 10-year research programme “Arctic Ocean 2050”, as well as the upcoming HiAOOS research cruise.
Filling a long-standing gap
For almost two decades, researchers have lacked a widely used satellite product capable of routinely providing information on Arctic sea-ice trajectories over long periods. Now we present LiMOSAT, a new system that uses synthetic aperture radar (SAR) observations from satellite missions such as the European Sentinel-1 and Canadian RADARSAT-2 to track sea-ice movement across large areas of the Arctic. The system tracks how Arctic sea ice drifts, deforms, and fractures, providing new insights into how it is changing in a warming climate.
By following individual ice parcels from one satellite image to the next, LiMOSAT reconstructs continuous pathways of ice motion and deformation history over weeks to months. The work builds on the legacy of the RADARSAT Geophysical Processor System (RGPS), which routinely provided similar information between 1996 and 2008, with a lower precision. LiMOSAT brings this capability into the era of modern satellite missions, laying the foundation for more reliable long-term studies of Arctic sea-ice dynamics and supporting safe ship navigation and other operations in the Arctic.
More than just movement
Following the path of drifting ice reveals more than where the ice has been. Using the trajectories generated by LiMOSAT, researchers can map how the ice deforms as it moves. These deformation patterns show where the ice stretches apart to form leads, areas of open water between ice floes, and where it is compressed and forms ridges, much thicker, and rougher ice.
Such information is important for understanding the physical processes that shape the Arctic sea-ice cover. It also provides data that can be used to improve sea-ice and climate models, helping researchers better capture how the ice responds to changing environmental conditions.
Supporting Arctic operations
Sea-ice deformation is not only of interest to scientists. For vessels operating in ice-covered waters, information about leads, ridges, and heavily deformed ice can help identify safer and more efficient routes. Areas with thick, deformed, and ridged ice can present challenges for ships, while leads may offer easier passage through otherwise dense ice cover.
The new system therefore has potential applications for ice services, forecasting centers, and organisations that support navigation and other activities in the Arctic. It is currently supporting the first research cruise for the 10-year programme “Arctic Ocean 2050”. Sean Chua from the Nansen Center, main author of the study, provides the navigation team onboard RV Kronprins Haakon with daily updates on sea-ice conditions, produced with LiMOSAT. Read more about the ongoing cruise here. The system will also be used during the upcoming research cruise in the HiAOOS project, which is led by the Nansen Center. Read more about HiAOOS here.
Tested against observations
To evaluate the method, the researchers compared the satellite-derived trajectories with measurements from drifting buoys in the Arctic. The results show that LiMOSAT can reconstruct continuous sea-ice pathways over periods ranging from days to months, with good agreement between the SAR-derived trajectories and in situ observations from buoys. The system currently performs best during winter, when stable ice conditions make tracking easier. Further work is needed to improve performance during summer, but the LiMOSAT system is already proving its usefulness to support both research and operational services that depend on reliable information about Arctic sea ice.
Key researchers: Sean Chua, Anton Korosov, Einar Ólason
