EGU21-2395, updated on 10 Jan 2024
EGU General Assembly 2021
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Direct and indirect pathways of convected water masses and their impacts on the overturning dynamics of the Labrador Sea

Sotiria Georgiou1, Stefanie L. Ypma1,2, Nils Brüggemann3, Juan-Manuel Sayol1,4, Carine G. van der Boog1, Paul Spence5, Julie D. Pietrzak1, and Caroline A. Katsman1
Sotiria Georgiou et al.
  • 1Delft University of Technology, Delft, Netherlands (
  • 2Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Netherlands
  • 3Faculty of Mathematics, Informatics and Natural Sciences, University of Hamburg, Hamburg, Germany
  • 4Department of Applied Mathematics, University of Alicante, Sant Vicent del Raspeig, Alicante, Spain
  • 5School of Geosciences, University of Sydney, NSW, Australia.

The dense waters formed by wintertime convection in the Labrador Sea play a key role in setting the properties of the deep Atlantic Ocean. To understand how variability in their production might affect the Atlantic Meridional Overturning Circulation (AMOC) variability, it is essential to determine pathways and associated timescales of their export. In this study, we analyze the trajectories of Argo floats and of Lagrangian particles launched at 53oN in the boundary current and traced backwards in time in a high‐resolution model, to identify and quantify the importance of upstream pathways. We find that 85% of the transport carried by the particles at 53oN originates from Cape Farewell, and it is split between a direct route that follows the boundary current and an indirect route involving boundary‐interior exchanges. Although both routes contribute roughly equally to the maximum overturning, the indirect route governs its signal in denser layers. This indirect route has two branches: part of the convected water is exported rapidly on the Labrador side of the basin, and part follows a longer route towards Greenland and is then carried with the boundary current. Export timescales of these two branches typically differ by 2.5 years. This study thus shows that boundary‐interior exchanges are important for the pathways and the properties of water masses arriving at 53oN. It reveals a complex three‐dimensional view of the convected water export, with implications for the arrival time of signals of variability therein at 53oN and thus for our understanding of the AMOC.

How to cite: Georgiou, S., Ypma, S. L., Brüggemann, N., Sayol, J.-M., van der Boog, C. G., Spence, P., Pietrzak, J. D., and Katsman, C. A.: Direct and indirect pathways of convected water masses and their impacts on the overturning dynamics of the Labrador Sea, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2395,, 2021.


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