New insights on the flow of hot water from the Gulf Stream all the way to the Arctic

At a time when social media loses its nerves on how variations of the Gulf Stream will melt the Arctic sea ice, two recent articles remind us that the proverbially warm Atlantic Waters have to cross the Nordic Seas and its complex ocean circulation. There is no way around them. 
The first paper by Raj et al. shows how satellite data can be used to measure the transport of Atlantic Water across the narrow straits between Iceland, the Færoes and the Shetlands and the large influence of the winds of the North Atlantic Oscillation. We now have the opportunity to continuously monitor the variability in the amount of Atlantic Water supplied to the Nordic seas (and it’s only a few percents of the whole Gulf Stream). 
A second paper by Chatterjee et al. focuses further North on the Fram Strait, where sea ice makes quantification by satellite data impossible but model results such as the TOPAZ reanalysis can be used for support. The study reveals how the changes of wind-driven cyclonic circulation of the Greenland Sea precede the changes of Atlantic Water temperature in the Fram Strait, rather than other changes upstream and makes the story of Gulf Stream waters reaching the Arctic Ocean even slightly more epic than it was before: the local winds on the Nordic Seas have a lot to say. 

Figure 1.: Schematic of major currents in the Nordic Seas. The red arrows indicate the Atlantic Water pathways, while the hollow blue arrows indicate the gyre circulations. The solid blue line shows the polar water flow in the East Greenland Current. Location of vertical sections, Fram Strait (79°N, 5–9°E) and Svinøy (62–65°N, 5–0°W), are indicated with green lines. The contours indicate the bottom topography with contour interval 1,000 m (see Furevik & Nilsen, 2005; Raj et al., 2016 for details).


Raj R.P., J.E.Ø. Nilsen, J.A. Johannessen, T. Furevik, O.B. Andersen, L. Bertino. Quantifying Atlantic Water transport to the Nordic Seas by remote sensing, Remote Sensing of Environment, 216, 2018, pp 758-769,
Chatterjee, S., Raj, R. P., Bertino, L.,Skagseth, Ø., Ravichandran, M., & Johannessen, O. M. (2018). Role of Greenland Sea gyre circulation on AW temperature variability in the Fram Strait. Geophysical Research Letters, 1–8.

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