Mapping Deep Ocean Currents: Uncovering the Hidden Pathways of Overflow Waters
The recent SWERVE funded FAROX cruise, led by Léon Chafik on RV Skagerak, set out to explore how dense overflow waters move between the Nordic Seas and the North Atlantic. By collecting unprecedented measurements of temperature, salinity, currents, and turbulence, the team mapped deep currents and investigated their role in shaping the climate system.
The Atlantic Ocean. Photo: Léon Chafik.
What is the main goal of this cruise, and what kinds of data are you collecting?
Léon Chafik on RV Skagerak. Photo: private.
The aim of the FAROX cruise was to understand how dense overflow waters cross the Iceland–Faroe Ridge and the Faroe–Shetland Channel. To do this, we collected temperature, salinity, current, and turbulence data to see how these waters move and mix as they pass through these passages. In total, we carried out 154 CTD stations—an unusually high number for a cruise of this length—to map the deep currents in the region and measure their properties, currents we still know very little about.
To collect this data, what instruments are you using?
We used CTDs to measure temperature and salinity throughout the water column, LADCPs to record current velocities with depth, and the ship’s ADCP for continuous current monitoring along our cruise track. We also used a vertical microstructure profiler (VMP) in the Faroe–Shetland Channel to measure turbulence.
What’s a typical day like onboard for the research team?
Crew on RV Skagerak. Photo: Léon Chafik.
There is no true “normal” day at sea, but the rhythm is intense. The team worked in shifts around the clock — some operating the CTD and VMP, others processing data as soon as it was collected, while continuously planning the next stations. The weather and sea conditions determined if we could proceed to the next station or section.
Did you encounter any surprising findings or challenges during the cruise?
Yes! We expected strong currents, but surprised us most was the intensity of the tides over the ridge near Iceland. They were much stronger than anticipated and may also have some influence on the overflow waters crossing the Iceland–Faroe Ridge.
Read the full article on swerve.se
The Swedish Research Vessel Infrastructure for Marine Research
