8.5      Evaluation of a scale-aware 3DTKE subgrid mixing parameterization in NWP applications.

Zhang, Xu, Baode Chen, Shanghai Typhoon Institute, Chinese Meteorological Administration, China, Jian-Wen Bao, PSD/ESRL/NOAA

A new three-dimensional (3D) turbulent kinetic energy (TKE) subgrid mixing scheme is developed using the Advanced Research version of the Weather Research and Forecasting Model (ARW-WRF) to address the gray-zone problem in the parameterization of subgrid turbulent mixing. The new scheme combines the horizontal and vertical subgrid turbulent mixing into a single energetically consistent framework, in contrast to the conventionally separate treatment of the vertical and horizontal mixing. The new scheme is self-adaptive to the grid size change between the large-eddy simulation (LES) and mesoscale limits. A series of real cases are carried out to evaluate the scheme in the Shanghai Meteorological Service (SMS) operational NWP model. Results from real-case simulations show the feasibility of using the new scheme in the WRF model in lieu of the conventional treatment of subgrid mixing.