摘要
基于对流边界层“一阶模型”,并考虑机械湍流和夹卷过程对对流边界层发展的贡献,提出了对流边界层顶部夹卷速度参数化的改进方案.理论分析表明,在对流边界层受热力湍流和机械湍流共同驱动的情况下,夹卷速度的参数化方案中应该包括机械湍流、热力湍流、夹卷过程和边界层顶上自由大气的逆温强度.用1979年7月美国CIRCE试验的边界层观测资料对改进后的参数化方案进行了对比验证,结果表明新方案能很好地预报对流边界层高度的演变过程.这一改进不仅使物理意义更加合理,也使夹卷速度参数化方案与实际大气状况符合得更好.
Based on the ＂first-order model＂ of convective boundary layer （CBL）, an improved parameterization for the entrainment rate of CBL was proposed. Analyses show that when the CBL is driven by both shear and buoyancy-turbulence, not only the contribution of buoyancy turbulence, but also the contributions of mechanical turbulence and entrainment process should be taken into account. The data measured during Central Illinois Rainfall Chemistry Experiment （CIRCE） were used to verify the validity of the improved parameterization. The results show that the new parameterization scheme can predict the development of the CBL height very nicely. This indicates that the improvement is reasonable and the new parameterization is applicable.
基金
国家自然科学基金项目(40475009)资助
关键词
对流边界层
夹卷速度
参数化
一阶模型
机械湍流
convective boundary layer
entrainment rate
parameterization
first-order model
mechanical turbulence
