The Numerical Representation of Entrainment in Parameterizations of Boundary Layer Turbulent Mixing
The Numerical Representation of Entrainment in Parameterizations of Boundary Layer Turbulent Mixing
复制标题
边界层湍流混合参数化中夹带的数值表示
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
A. Lock
中科院分区：
文献类型：
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作者：
A. Lock
摘要对流边界层的参数化问题，特别是其数值处理的帽反演已被确定。结果表明，湍流方案可以联合收割机与沉降的数值表示，产生非物理夹带，也确定了由Lenderink和Holtslag。对Lock等人的边界层参数化方法提出了一种修正，在该方法中，从每一时间步的平均热力学廓线诊断出一种不连续的反演。这样就可以对逆温区域的亚网格尺度过程进行一致的处理。特别是，参数化的湍流夹带通量可以进行调整，以允许从湍流混合和垂直平流的冲突表示所产生的虚假夹带。它还允许湍流和辐射通量之间的直接耦合，以确保云顶辐射冷却在反演网格水平和混合网格之间正确分布。
Abstract Problems have been identified with parameterizations of convective boundary layers, in particular with their numerical treatment of the capping inversion. It is shown that the turbulence scheme can combine with the numerical representation of subsidence to produce unphysical entrainment, as was also identified by Lenderink and Holtslag. A correction is proposed for the Lock et al. boundary layer parameterization in which a discontinuous inversion is diagnosed from the mean thermodynamic profiles every time step. This then allows a consistent treatment of subgrid-scale processes in the region of the inversion. In particular, the parameterized turbulent entrainment flux can be adjusted to allow for the spurious entrainment arising from the conflicting representations of turbulent mixing and vertical advection. It also allows a direct coupling between the turbulent and radiative fluxes to ensure that cloud-top radiative cooling is correctly distributed between the inversion grid level and the mixed ...