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Detailed Reference Information |
Bouruet-Aubertot, P., Mercier, H., Gaillard, F. and Lherminier, P. (2005). Evidence of strong inertia-gravity wave activity during the POMME experiment. Journal of Geophysical Research 110: doi: 10.1029/2004JC002747. issn: 0148-0227. |
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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 Oc¿an Multidisciplinaire M¿so 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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Abstract |
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Keywords
Oceanography, Physical, Internal and inertial waves, Oceanography, Physical, Turbulence, diffusion, and mixing processes, Oceanography, Physical, Upper ocean and mixed layer processes, inertia-gravity waves, turbulent mixing |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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