Observation of submesoscale turbulence in a mesoscale eddy
Abstract
Submesoscale, defined as the scale range between the first baroclinic deformation radius and the thickness of the turbulence boundary layer, provides a dynamical conduit for energy transfer from mesoscale towards microscale dissipation. However, it is not clear how the submesoscale turbulence is presented in a coherent rotational mesoscale eddy. Here we report results from a high-resolution measurement of submesoscale turbulence in a mesoscale eddy with a slight southward tilt with depth. The energy spectrum in the mesoscale eddy is decomposed into mesoscale (geostrophic eddy) and submesoscale (inertia-gravity wave) components with different spectral slopes. The spectral energy at mesoscale has a -3.62±0.52 slope at subsurface, then levels off with depth because of the intensifying of the ageostrophic effect. At submesoscale, the slope is -1.73±0.51 and weakly independent on depth. The length scale of transition from mesoscale to submesoscale is quantitatively identified by using wave-vortex method, which is 45 km and has a relatively weak dependence on depth.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMOS33B1462Z
- Keywords:
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- 4504 Air/sea interactions;
- OCEANOGRAPHY: PHYSICAL;
- 4512 Currents;
- OCEANOGRAPHY: PHYSICAL;
- 4520 Eddies and mesoscale processes;
- OCEANOGRAPHY: PHYSICAL;
- 4572 Upper ocean and mixed layer processes;
- OCEANOGRAPHY: PHYSICAL