TY - JOUR T1 - A near-inertial mode observed within a Gulf Stream warm-core ring A1 - Joyce,Terrence M. A1 - Toole,John M. A1 - Klein,Patrice A1 - Thomas,Leif N. AD - Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. AD - IFREMER, Lab Phys Oceans, Plouzane, France. AD - Stanford Univ, Dept Environm Earth Syst Sci, Stanford, CA 94305 USA. UR - https://archimer.ifremer.fr/doc/00148/25929/ DO - 10.1002/jgrc.20141 KW - near-inertial waves KW - warm-core ring KW - velocity fine structure N2 - Layering of ocean velocity fine structure has been coherently observed across the entire extent of a Gulf Stream warm-core ring using a shipboard acoustic Doppler current profiler system in September 2009 and independently sampled as the ring transited a moored array. Lines of constant velocity phase generally followed isopycnals as they deepened within the ring center. We also observed a clear separation of the vertical structure of the flows associated with the ring (of order 0.5m/s) with the shorter (200m) and less energetic (similar to 0.2m/s) flows of the velocity fine structure, which was further observed to rotate clockwise with increasing depth, consistent with downward propagating near-inertial waves (NIWs). Observations are consistent with a ring-scale NIW packet, probably wind forced, that shows enhanced NIW energy within the sloping pycnocline at depths of 300-700m. Evidence of wind-forced NIWs within anticylonic eddies in a numerical simulation shows some similar features to our observations, which we try to understand physically with basic WKB-type wave/current dynamics along the lines of previously published work and a new calculation of NIW trapping within an isolated, baroclinic vortex. Y1 - 2013/04 PB - Amer Geophysical Union JF - Journal Of Geophysical Research-oceans SN - 0148-0027 VL - 118 IS - 4 SP - 1797 EP - 1806 ID - 25929 ER -