Evidence of strong inertia-gravity wave activity during the POMME experiment
| Type | Article | ||||||||
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| Date | 2005-06 | ||||||||
| Language | English | ||||||||
| Author(s) | Bouruet-Aubertot Pascale3, Mercier Herle 1, 2, Gaillard Fabienne2, Lherminier Pascale2 |
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| Affiliation(s) | 1 : CNRS, Univ Paris 06, Inst Rech Dev, UMR 7617,Inst Pierre Simon Laplace, Lab Oceanog & Climat Expt & Approches Numer, F-75252 Paris, France. 2 : Univ Bretagne Occidentale, Inst Francais Rech Exploitat Mer, CNRS,UMR 6523, Lab Phys Oceans, Plouzane, France. 3 : Univ Paris 06, Inst Rech Dev, UMR 7617,Inst Pierre Simon Laplace, Lab Oceanog & Climat Expt & Approches Numer, F-75252 Paris, France. |
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| Source | Journal of Geophysical Union - Research C - Oceans (0148-0227) (American Geophysical Union), 2005-06 , Vol. 110 , N. C7 | ||||||||
| DOI | 10.1029/2004JC002747 | ||||||||
| WOS© Times Cited | 9 | ||||||||
| Keyword(s) | Turbulent mixing, Tnertia gravity waves | ||||||||
| Abstract | The purpose of this paper is to characterize inertia-gravity waves (IGW) activity and to investigate the variability of these waves in relationship to atmospheric forcing and larger-scale motions. To this aim, we analyzed Eulerian measurements of horizontal currents and temperature collected over 1 year during the Programme Océan Multidisciplinaire Méso Echelle (POMME). We focused on the main frequency components of the IGW spectrum, namely the inertial frequency f and the semidiurnal frequency M2. Time evolution of the relative energy of these two components gave evidence of isolated events of high intensity. We performed a detailed analysis of these events and identified mechanisms of generation of these waves. Localized spots of intense, near-inertial IGW were observed in winter. During the mixed layer deepening, one event was correlated with plume-like structures resulting from peaks of intense surface cooling. This suggests a local generation process driven by strong downward vertical motions. Instead, other events of strong IGW could be related to submesoscale features, characteristic of a frontal region, in particular, wave trapping within anticyclonic eddies. In contrast, a downward energy propagation down to about 500 m below the mixed layer was isolated after a stormy period. Eventually, internal tidal beams, possibly generated at a nearby seamount, intermittently crossed the mooring, though less energetically than the previous events. Last, we estimated the eddy diffusivity from the velocity vertical shear. Large variations were obtained, from 10-6 m2/s up to 10-3 m2/s, consistent with the intense events previously isolated. | ||||||||
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