A new study supported by OSNAP, ObsSea4Clim and EuroSea has been recently published.

The Atlantic Meridional Overturning Circulation (AMOC) is important for the global climate due to its role in redistributing heat, freshwater, and dissolved gases over broad spatial scales. Through continuous observations, we now have an 8-year (2014–2022) time series of volume, heat and freshwater transports in the subpolar North Atlantic (∼60°N). Using these data, our analysis focuses on characterizing the interannual variability of the AMOC. We first investigated the importance of boundary currents and found that any single boundary current can account for up to ∼30% of the total AMOC interannual variability. Using a number of data sets, we then quantified the relationship between the water mass formation through surface cooling and freshening, the storage of water masses in ocean basins, and the AMOC on interannual timescales. We find an expected relationship in the eastern subpolar basin (between Greenland and the UK), where formation leads to increased basin storage, which further results in enhanced AMOC.

The full article is available here:

Fu, Y., Lozier, M. S., Bower, A., Burmeister, K., Carrilho Biló, T., Cyr, F., et al. (2025). Characterizing the interannual variability of North Atlantic subpolar overturning. Geophysical Research Letters, 52, e2025GL114672. https://doi.org/10.1029/2025GL114672