What can Hydrography Tell Us About the Strength of the Nordic Seas MOC Over the Last 70 to 100 Years?

Abstract

The flow of warm water into the Nordic Seas plays an important role for the mild climate of central and northern Europe. Here we estimate the stability of this flow thanks to the extensive hydrographic record that dates back to the early 1900s. Using all casts in two areas with little mean flow just south and north of the Greenland-Scotland Ridge that bracket the two main inflow branches, we find a well-defined approximately ±0.5 Sv volume transport (and a corresponding ±30 TW heat flux) variation in synchrony with the Atlantic multidecadal variability that peaked most recently around 2010 and is now trending down. No evidence is found for a long-term trend in transport over the last 70 to 100 years.