TURBULENT VISCOSITY IN CRITICAL LAYER OF ZONAL FLOW

The turbulent viscosity functional for a thin critical layer of barotr opic Rossby wave propagation in a zonal shear flow with large-scale tw o-dimensional turbulence is defined in the mean field approximation. A n assumption is taken that correlation length of turbulent velocity pu lsations is larger than the thickness of the critical layer while thei r correlation time is sufficiently small. The Boussinesq hypothesis is verified for such a turbulence and an explicit form of the turbulent viscosity coefficient is obtained. The spectral interpretation is give n for the mechanism of the turbulent viscosity formation.