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

• Published in: Geophysical Research Letters
• Main Authors: Klymak, Jody M., Shearman, R. Kipp, Gula, Jonathan, Lee, Craig M., D'Asaro, Eric A., Thomas, Leif N., McWilliams, James C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geophysical Research Letters 2016
• Subjects: ocean mixing; Gulf Stream; submesoscale mixing; eddies; Harper; North Atlantic
• Online Access: http://hdl.handle.net/1828/12347; https://doi.org/10.1002/2015GL067152

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. Our thanks to the captains and crews of R/V Knorr and R/V Atlantis, and our technicians who made this work possible. The AVHRR Oceans Pathfinder SST data were obtained from the Physical Oceanography Distributed Active Archive Center (PO.DAAC) at the NASA Jet Propulsion Laboratory, Pasadena, California, http://podaac.jpl.nasa.gov. The bulk of this work was funded under the Scalable Lateral Mixing and Coherent Turbulence Departmental Research Initiative and the Physical Oceanography Program of the Office of Naval Research, program officers Terri Paluszkiewicz and Scott Harper. The data used in this paper can be found at http://web.uvic.ca/∼jklymak/LM12/GulfStreamPaper/. Faculty Reviewed