Stochastic Subgrid Parameterizations for Simulations of Atmospheric Baroclinic Flows
Stochastic Subgrid Parameterizations for Simulations of Atmospheric Baroclinic Flows
复制标题
大气斜压流模拟的随机子网格参数化
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
J. Frederiksen
中科院分区：
文献类型：
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作者：
M. Zidikheri;J. Frederiksen
摘要采用随机次网格模拟方法，对具有大尺度急流和大气典型能谱的斜压气流进行了大涡模拟（LES），并对水平和垂直次网格尺度传输进行了参数化。该方法表示的亚网格尺度涡LES（在T63和T31的分辨率）的随机模型，考虑到湍流涡的记忆效应。该模型的统计数据是从一个更高的分辨率（T126）直接数值模拟（DNS）。模拟采用准地转两层模式，亚网格项在垂直方向上是不均匀的，在水平方向上是各向异性的，在每个波数上用2 × 2矩阵表示。参数化在截断的最大总波数附近的尖点处具有最大幅度。在T63处，矩阵的非对角元素是可忽略的（对应于有效解耦的水平），并且对角元素几乎是各向同性的。在较低的分辨率下，
Abstract A stochastic subgrid modeling method is used to parameterize horizontal and vertical subgrid-scale transfers in large-eddy simulations (LESs) of baroclinic flows with large-scale jets and energy spectra typical of the atmosphere. The approach represents the subgrid-scale eddies for LES (at resolutions of T63 and T31) by a stochastic model that takes into account the memory effects of turbulent eddies. The statistics of the model are determined from a higher-resolution (T126) direct numerical simulation (DNS). The simulations use a quasigeostrophic two-level model and the subgrid terms are inhomogeneous in the vertical and anisotropic in the horizontal and are represented by 2 × 2 matrices at each wavenumber. The parameterizations have the largest magnitudes at a cusp near the largest total wavenumbers of the truncations. At T63 the off-diagonal elements of the matrices are negligible (corresponding to effectively decoupled levels) and the diagonal elements are almost isotropic. At the lower resol...