湍流动能参数化在中尺度模式中的应用研究

在中尺度区域模式MM4的基础上对其中的湍流参数化方法作了改进，用湍流动能参数化方法代替原有的总体边界方案中的局地K闭合，以高精度边界层方案作为控制方案，重点对1997－07－17的徐州暴雨进行了模拟。对湍流场的计算表明，这种闭合得到了合理的湍流场，代入模式计算稳定，预报的各物理量空间分布和原来的预报场相似，24h降水预报的位置没有改进，但是降水量所提高，表明湍流动能事方法代替局地K闭合是一种有希望的研究方向。该方法得到了比原模式中的湍流闭合方案更加合理的湍流扩散参数，对中尺度模式的改进有所帮助。

The Study of Kinematic Turbulence Parameterization in Meso-scale Numerical Weather Forecast

The improvement to the turbulence parameterization of meso scale forecast model MM4 was presented.A turbulent kinematic energy(TKE)parameterization is used all over the forecast time in the whole model region to take the local K theory's place in the bulk aerodynamic parameterization of the host model MM4,while MM4 with the high resolution PBL parameterization is used as control forecast.MM4 with different parameterizations was utilized on the forecast of rainstorm on July 17,1997,and new TKE parameterization introduced a reasonable distribution of turbulent variables.The computational stability is good and the forecast results of different variables are close to or better than those of the control model,Although locations of the strongest rainfall do not show any improvement,the amount of the 24 hour rainfall is larger than that forecasted by the control model.This amount is still not as large as the actual rainfall,but this result shows that the TKE parameterization is encouraging.The application of TKE parameterization readjusts the distribution of eddy viscosity, K m,and hence improves the model.