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PHY-04  Cross-scale interactions: mesoscale and smaller
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Observed equatorward propagation and chimney effect of near-inertial waves in the midlatitude ocean
Xiaolong Yu* , Sun Yat-sen University
Alberto C. Naveira Garabato, Ocean and Earth Science, University of Southampton, Southampton, UK
Clément Vic, Laboratoire d’Océanographie Physique et Spatiale (LOPS), University Brest, CNRS, IRD, Ifremer, IUEM, Brest, France
Jonathan Gula, Laboratoire d’Océanographie Physique et Spatiale (LOPS), University Brest, CNRS, IRD, Ifremer, IUEM, Brest, France
Anna C. Savage, Scripps Institution of Oceanography, University of California, San Diego, CA, USA
Jinbo Wang, M/S 300-323C, 4800 Oak Grove Drive, Pasadena, CA, USA
Amy F. Waterhouse, Scripps Institution of Oceanography, University of California, San Diego, CA, USA
Jennifer A. MacKinnon, Scripps Institution of Oceanography, University of California, San Diego, CA, USA |
The propagation characteristics of near-inertial waves (NIWs) and how mesoscale and submesoscale processes affect the waves' vertical penetration are investigated using observations from a mooring array located in the northeast Atlantic. The year-long observations show that near-inertial motions are mainly generated by local wind forcing, and that they radiate equatorward and downward following several strong wind events. Observational estimates of horizontal group speed typically exceed those of vertical group speed by two orders of magnitude, consistent with predictions from the dispersion relation. Enhanced near-inertial kinetic energy and vertical shear are found only in mesoscale anticyclones with Rossby number of O(0.1). By contrast, submesoscale motions with order one Rossby number have little effect on the trapping and vertical penetration of NIWs, due to their smaller horizontal scales, shorter time scales, and confined vertical extent compared to mesoscale eddies. |
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