Submesoscale streamers exchange water on the north wall of the Gulf Stream

• Main Authors: Klymak, Jody M., Shearman, R. Kipp, Gula, Jonathan, Lee, Craig M., D'Asaro, Eric A., Thomas, Leif N., Harcourt, Ramsey R., Shcherbina, Andrey Y., Sundermeyer, Miles A., Molemaker, Jeroen, McWilliams, James C.
• Format: Article in Journal/Newspaper
• Language: English; unknown
• Published: John Wiley & Sons, Inc.
• Subjects: North Atlantic
• Online Access: https://ir.library.oregonstate.edu/concern/articles/vh53x1362

The Gulf Stream is a major conduit of warm surface water from the tropics to the subpolar North Atlantic. Here we observe and simulate a submesoscale (<20 km) mechanism by which the Gulf Stream exchanges water with subpolar water to the north. Along isopycnals, the front has a sharp compensated temperature-salinity contrast, with distinct mixed water between the two water masses 2 and 4 km wide. This mixed water does not increase downstream despite substantial energy available for mixing. A series of streamers detrain this water at the crest of meanders. Subpolar water replaces the mixed water and resharpens the front. The water mass exchange accounts for a northward flux of salt of 0.5–2.5 psu m² s⁻¹, (large-scale diffusivity O (100 m² s⁻¹)). This is similar to bulk-scale flux estimates of 1.2 psu m² s⁻¹ and supplies fresher water to the Gulf Stream required for the production of 18° subtropical mode water. Keywords: ocean mixing, eddies, Gulf Stream, submesoscale mixing