The role of water mass transformation in setting the seasonal to interannual variability in the subpolar North Atlantic overturning ...

• Main Authors: Evans, D. Gwyn, Holliday, Penny, Bacon, Sheldon, Le Bras, Isabela
• Format: Conference Object
• Language: unknown
• Published: GFZ German Research Centre for Geosciences 2023
• Subjects: NADW; North Atlantic Deep Water; North Atlantic
• Online Access: https://dx.doi.org/10.57757/iugg23-0844; https://gfzpublic.gfz-potsdam.de/pubman/item/item_5016633

<!--!introduction!--> The overturning streamfunction as measured at the OSNAP (Overturning in the Subpolar North Atlantic Program) mooring array represents the transformation of warm/salty Atlantic Water into cold/fresh North Atlantic Deep Water (NADW). The magnitude and variability of the overturning at the OSNAP mooring array can therefore be linked to the water mass transformation by air--sea buoyancy fluxes and mixing in the region to the north of the OSNAP array. Here, we estimate these water mass transformations using a combination of observational-based, reanalysis-based and model-based datasets. Our results highlight that air-sea fluxes alone cannot account for the time-mean magnitude of the overturning at OSNAP, and therefore a residual mixing-driven transformation is required to explain the difference. Further we show that the seasonal to interannual variability of the overturning streamfunction at OSNAP cannot be linked to changes in the transformation by air--sea fluxes and mixing. This ... : The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) ...