Fig. 3: Lagrangian meridional overturning stream function.

a Meridional overturning stream function in a) temperature-latitude, b salinity-latitude, and c density-latitude coordinate system. This has been computed using equation (3) and with trajectories that have exited the eastern Subpolar North Atlantic Ocean (SPNA) section southward. The orange lines indicate Atlantic inflows and blue dashed lines correspond to Arctic waters that have reached the eastern SPNA. The direction of the water movement in each figure is indicated by arrows. The solid streamlines are 2 Sv apart and start at 1 Sv. Similarly, the dashed streamlines are plotted with 1 Sv interval and start at -1 Sv. The Atlantic and Arctic water contribution to the Atlantic Meridional Overturning Circulation (AMOC) lower limb are shown with bold orange and blue numbers respectively.