TURBULENCE IN BROKEN LEE WAVES

In this paper, the waves’ breaking in the lee waves is successfullysimulated by the atmospheric mesoscale numerical model with a second-order tur-bulent closure. It is further proved that the turbulence in the wave-breaking regionplays the role of intense mixing for the average field, which leads to the trappingof upward propagating waves and thus promotes the development of the downslopewind. The turbulent structure in the wave-breaking region is discussed and the fol-lowing conclusions are obtained: (1) In the wave-breaking region, the turbulent heatfluxes transfer from inside to outside and the turbulent momentum fluxes transferfrom outside to inside. (2) In the wave-breaking region, the turbulent energy mainlycomes from the wind shear and the buoyancy promotes the turbulent developmentonly in part of the region. (3) In the upper part of the wave-breaking region, theturbulent momentum fluxes behave as a counter-gradient transfer. (4) The turbulentmixing in the wave-breaking region is non-local.