Year: 2024
Type: article
Abstract: The Atlantic Meridional Overturning Circulation entails vigorous thermohaline transformations in the subpolar North Atlantic Ocean (SPNA). There, warm and saline waters originating in the (sub)tropics are converted into cooler and fresher waters by a combination of surface fluxes and sub‐surface mixing. Using microstructure measurements and a small‐scale variance conservation framework, we quantify the diapycnal and isopycnal contributions –by microscale turbulence and mesoscale eddies, respectively– to thermohaline mixing within the eastern SPNA. Isopycnal stirring is found to account for the majority of thermal (65%) and haline (84%) variance dissipation in the upper 400 m of the eastern SPNA. A simple dimensional analysis suggests that isopycnal stirring could account for (5–10) Sv of diahaline volume flux, suggesting an important role of such stirring in regional water‐mass transformations. Our mixing measurements are thus consistent with recent indirect estimates in highlighting the importance of isopycnal stirring for North Atlantic overturning.
DOI: 10.1029/2023jc020817
Institutions: National Oceanography Centre, University of Southampton, Universidade de Vigo, Centre National de la Recherche Scientifique, Ifremer, Laboratory for Ocean Physics and Satellite Remote Sensing, Institut Universitaire Européen de la Mer, Institut de Recherche pour le Développement, Consejo Superior de Investigaciones Científicas, Instituto de Investigacións Mariñas, Woods Hole Oceanographic Institution
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Life below water
Open Access status: hybrid
Estimated APC paid: $3,880
Awards: G121809054, G1270187747, G1426560549, G1540078672, G2241543201, G2309174360, G2660406951, G3359367016, G3480869486, G3690828678, G4185898865, G4676842746, G5044100751, G5080475149, G5402437505, The Gulf Stream control of the North Atlantic carbon sink, G6340923058, G7084143925, G7485930139, G7550537929, NI - Dissolved Organic matter subduction and transport along the east Greenland MArgin (DOGMA), G8286186998, G8522113391, G8684520763, G897484643
OpenAlex ID: W4402657404