Tall oceanic mooring in the central Fram Strait from NorEMSO ready for another year

An RBR CTD with oxygen sensor is recovered from the Fram Strait. Trine Lise Sviggum Helgerud, Norwegian Polar Institute.

In September 2023, the central Fram Strait mooring F10 was serviced by the Norwegian Polar Insitute as part of the Nordic Seas node NorEMSO. This site forms an important component of the wider observing system across the Fram Strait, the largest gateway to the Arctic Ocean, monitoring in- and outflow from the Arctic. 

This mooring site is at the front of the East Greenland Current, i.e. west of it is the southward flowing cold and fresh Polar Water while on the east of it, we find warm and salty Atlantic Water. With F10, which is over a water depth of 2650 m, we monitor how these water masses vary and how the current ’s dynamics is during the year, in relation to the sea ice variations in this area. With observing the variability over longer time we have seen that there was much more Atlantic Water present in winter time in the late 2010s with big impact on the sea ice cover, while in the last two years there is more Arctic outflow again.

Upon arrival on the mooring site in September 2023, it first appeared impossible to retrieve the mooring as it was fully covered by the drift ice of the East Greenland Current. Later during the cruise, by checking carefully the satellite images, we noted a short period with less sea ice and headed out directly to recover it. This went smooth and within one hour it was all on deck – a new record. Unfortunately, one CTD with oxygen sensor had stopped working mid-way through. Now all temperature, salinity, oxygen, current meter sensors, and also pH and pCO2 sensors have been redeployed for another year until September 2024.

Author(s) Laura de Steur, Norwegian Polar Institute