Upper Ocean Turbulence from High-Resolution 3D Simulations

• DOI: 10.1175/2007jpo3773.1
• Publication Date: 2008-08-07T18:01:43Z
• Authors: Patrice Klein; Bach Lien Hua; Guillaume Lapeyre; Xavier Capet; Sylvie Le Gentil; Hideharu Sasaki
• Keywords: Rossby number; Frontogenesis; Sea-surface height

Abstract The authors examine the turbulent properties of a baroclinically unstable oceanic flow using primitive equation (PE) simulations with high resolution (in both horizontal and vertical directions). Resulting dynamics in surface layers involve large Rossby numbers significant vortical asymmetries. Furthermore, ageostrophic divergent motions associated small-scale frontogenesis are shown to significantly alter nonlinear transfers kinetic energy consequently time evolution dynamics. Such impact explains emergence cyclone–anticyclone asymmetry strong restratification upper layers, which not allowed by quasigeostrophic (QG) or (SQG) theory. However, despite this character, some main surprisingly still close equilibrium. They include noticeable shallow (≈k−2) velocity spectrum as well conspicuous local spectral relationship between energy, sea height, density variance over range scales (from 400 4 km). velocities can be remarkably diagnosed from only SQG relations. This suggests that validity specific relations extends dynamical regimes numbers. interior dynamics, on other hand, strongly differ involving small number, steep (≈k−4) spectrum, somewhat steeper spectrum. compensation destratification at depth confirms connection induced motions.