Spectral diffusivity

From Glossary of Meteorology

spectral diffusivity

A form of eddy viscosity or eddy diffusivity that varies with eddy size.

For a spectrum of turbulent eddy sizes there is a spectrum of diffusivities. By integrating over all eddy sizes and diffusivities, the total effect of turbulence can be approximated. This is a form of nonlocal turbulence closure and can be shown to be related to transilient turbulence theory.

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