The next CIRFA seminar will be presented by our colleague Hiroshi Sumata from the Norwegian Polar Institute.
TITLE: Unprecedented decline of sea ice thickness and ice export through Fram Strait in 2018
WHEN: 18 February 2021, 14:00-15:00.
Fram Strait is the major gateway connecting the Arctic Ocean and northern North Atlantic Ocean, where 80 – 90% of sea ice export from the Arctic Ocean takes place. The exported ice is the main source of freshwater maintaining surface stratification of the Nordic Sea, thereby preconditions European climate and deep-water formation in the downstream North Atlantic Ocean. The Fram Strait Arctic Outflow observatory maintained by the Norwegian Polar Institute has been monitoring sea ice thickness in Fram Strait by upward-looking sonars and ice profiling sonars since 1990. In 2018, the observatory captured an unprecedented decline of ice thickness in Fram Strait. Sea ice export estimated from the ice thickness measurements revealed that the 2018 ice export was less than half of the preceding 8 years average and one-third (quarter) of the 2000s (1990s). The minimum ice thickness and the concurrent minimum export were caused by an anomalous sea level pressure pattern over the Atlantic sector of the Arctic from fall of 2017 to summer of 2018. The result indicates that a drastic change of the freshwater export occurs not only by the ongoing Arctic-wide ice thinning but also by an anomalous atmospheric circulation in the Atlantic sector with an annual timescale.
Thomas, Andrea and Malin
Image: Sea ice feldwork with R/V Kronprins Haakon. Photographer: Marius Bratrein, chief engineer at NPI.