有切变对流边界层夹卷厚度参数化的大涡模拟研究

Parameterization of the entrainment zone depth above the sheared convective boundary layer derived from large-eddy simulations

运用大涡模拟研究有切变对流边界层顶部夹卷过程,并着重探讨了夹卷层厚度的参数化问题.结果表明,切变湍流对夹卷过程确有贡献,其作用应该被考虑在夹卷层厚度的参数化方案中.基于对现有两种参数化方案的验证与分析,本文提出了改进方案,新方案可以描述正压和斜压条件下的夹卷层厚度特征,而这两种条件下夹卷过程的不同特性可以通过在参数化方案中取不同的常数得到体现.

Large-eddy simulations are employed to investigate the entrainment process at the top of sheared convective boundary layer.The focused problem is how to parameterize the entrainment zone depth.Two previous parameterization schemes are evaluated by the data from large-eddy simulations,and a new scheme is suggested based on the analyses.The new scheme can describe the behaviours of entrainment zone depth under both barotropic and baroclinic conditions,while the different characteristics of the two kinds of entrainment can be embodied by using different coefficients.