Monitoring changes in sea-ice extent near West Jan Mayen Ridge in the Greenland Sea using Sentinel-1 SAR remote sensing data

Sea ice impacts the energy budget of the ocean both by regulating heat exchange with the atmosphere and through modifying the ocean’s freshwater budget by freezing, melting, and transporting freshwater in solid form. As such, sea ice acts as an important component of the climate system and plays a major role for dense-water formation at high latitudes. In the Greenland Sea, significant ice-edge retreat over the past century has been reported, impacting marine ecosystems as well as local dense-water formation and thus potentially the global overturning circulation. In this study, we provide an updated and robust analysis of the recent development of sea-ice extent in the Greenland Sea by using high-resolution Sentinel-1 SAR remote sensing data covering the period 2017 to 2024. After several years of small sea-ice extent, we observe particularly large sea-ice extent at the end of the study period in 2023 and 2024, with the largest extent found in January 2024, covering 20308 km 2 . Characteristic for the sea-ice extent in the Greenland Sea was its shape, the so-called Odden ice tongue which formed regularly near West Jan Mayen Ridge but had disappeared with the retreating ice edge. The remarkably large sea-ice extent in 2023 and 2024 strongly reminds of a re-occurrence of Odden. Further analysis of atmospheric conditions and sea-surface temperature in the study area suggests that the large sea-ice extent in 2023 and 2024 cannot be explained by a single driver but is the result of several interacting factors.