Nonhydrostatic Atmospheric Modeling Using a Combined Cartesian Grid
Nonhydrostatic Atmospheric Modeling Using a Combined Cartesian Grid
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DOI：
10.1175/2010mwr3252.1
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发表时间：
2010-10
影响因子：
3.2
通讯作者：
H. Yamazaki;T. Satomura
中科院分区：
文献类型：
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作者：
H. Yamazaki;T. Satomura
摘要 一种在笛卡尔网格上表示地形的新方法应用于二维非静水大气模型，以实现陡峭地形的高精度模拟。基于有限体积离散化的剃须单元方法与单元组合方法一起使用，其中小切割单元与相邻单元垂直或水平组合。独特的变量交错排列避免了表面压力的评估并减少了速度变量组合单元的计算成本，从而可以非常简单地计算动量方程。该方法成功地再现了各种斜坡上的流动，包括陡坡，在使用传统地形跟踪坐标的模型中观察到显着误差。水平单元组合在极陡坡上的优势也得到了证明。
Abstract A new method for representing topography on a Cartesian grid is applied to a two-dimensional nonhydrostatic atmospheric model to achieve highly precise simulations over steep terrain. The shaved cell method based on finite-volume discretization is used along with a cell-combining approach in which small cut cells are combined with neighboring cells either vertically or horizontally. A unique staggered arrangement of variables enables quite simple computations of momentum equations by avoiding the evaluation of surface pressure and reducing the computational cost of combining cells for the velocity variables. The method successfully reproduces flows over a wide range of slopes, including steep slopes where significant errors are observed in a model using conventional terrain-following coordinates. The advantage of horizontal cell combination on extremely steep slopes is also demonstrated.