A Global Model for the Diapycnal Diffusivity Induced by Internal Gravity Waves

Dirk.Olbers [ at ] awi.de


An energetically consistent model for the diapycnal diffusivity induced by breaking of internal gravity waves is proposed and tested in local and global settings. The model [Internal Wave Dissipation, Energy and Mixing (IDEMIX)] is based on the spectral radiation balance of the wave field, reduced by integration over the wavenumber space, which yields a set of balances for energydensity variables in physical space. A further simplification results in a single partial differentialequation for the total energy density of the wave field. The flux of energy to high vertical wavenumbers is parameterized by a functional derived from the wave–wave scattering integral of resonant wave triad interactions, which also forms the basis for estimates of dissipation rates and related diffusivities of ADCP and hydrography fine-structure data. In the current version of IDEMIX,thewaveenergyisforcedbywind-drivennear-inertialmotionsandbaroclinictides,radiatingwaves from the respectiveboundarylayers at the surfaceand the bottom into the ocean interior. The model predicts plausible magnitudes and three-dimensional structures of internal wave energy, dissipation rates, and dia- pycnal diffusivities in rough agreement to observational estimates. IDEMIX is ready for use as a mixing module in ocean circulation models and can be extended with more spectral components.

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Primary Division
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Peer revision
ISI/Scopus peer-reviewed
Publication Status
Eprint ID
DOI 10.1175/JPO-D-12-0207.1

Cite as
Olbers, D. and Eden, C. (2013): A Global Model for the Diapycnal Diffusivity Induced by Internal Gravity Waves , Journal of Physical Oceanography, 43 (8), pp. 1759-1779 . doi: 10.1175/JPO-D-12-0207.1



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