The HyperCASL algorithm: A new approach to the numerical simulation of geophysical flows
The HyperCASL algorithm: A new approach to the numerical simulation of geophysical flows
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HyperCASL 算法：地球物理流数值模拟的新方法
DOI：
10.1016/j.jcp.2009.05.025
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
D. Dritschel
中科院分区：
文献类型：
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作者：
Jérôme Fontane;D. Dritschel
本文描述了等高线-平流半拉格朗日（CASL）算法的一个主要扩展[D.G.]Dritschel， M.H.P. Ambaum，一种模拟精细尺度保守动力场的等高线-平流半拉格朗日数值算法，夸脱。j·罗伊。Meteorol。Soc. 123 (1997) 1097-1130；李志强，李志强，非绝热等高线平流半拉格朗日算法，气象学报，34(9)(2006):2503-2514。该扩展名为“HyperCASL”（HCASL），它使用了与CASL类似的材料位涡等高线的拉格朗日平流，但采用了单元内涡（VIC）方法来处理绝热强迫或阻尼。这样，HyperCASL在平流方面完全是拉格朗日的。与CASL一样，使用网格来处理“反演”（从位涡场计算速度场）。首先，描述了该算法的新方面，包括对底层CASL算法的几个改进。所有数值参数的选择都是为了在提高守恒性能的同时最小化计算成本。最后，使用二维无粘非强制湍流测试用例进行了彻底的代码间比较。这使我们能够指出与其他现有方法（即CASL， VIC和Pseudo-Spectral （PS）方法）相比，该新算法在分辨率，计算成本和数值扩散方面的优势。
We describe a major extension to the Contour-Advective Semi-Lagrangian (CASL) algorithm [D.G. Dritschel, M.H.P. Ambaum, A contour-advective semi-Lagrangian numerical algorithm for simulating fine-scale conservative dynamical fields, Quart. J. Roy. Meteorol. Soc. 123 (1997) 1097–1130; D.G. Dritschel, M.H.P. Ambaum, The diabatic contour advective semi-Lagrangian algorithm, Mon. Weather Rev. 134 (9) (2006) 2503–2514]. The extension, called ‘HyperCASL’ (HCASL), uses Lagrangian advection of material potential vorticity contours like CASL, but a Vortex-In-Cell (VIC) method for the treatment of diabatic forcing or damping. In this way, HyperCASL is fully Lagrangian regarding advection. A grid is used as in CASL to deal with ‘inversion’ (computing the velocity field from the potential vorticity field). First, the novel aspects of the algorithm are described including several improvements to the underlying CASL algorithm. All numerical parameters are chosen so as to minimise the computational cost while improving conservation properties. Finally, a thorough inter-code comparison is conducted using a two-dimensional inviscid unforced turbulence test-case. This enables us to point out the advantages of this new algorithm in terms of resolution, computational cost and numerical diffusion compared to other existing methods, namely CASL, VIC and Pseudo-Spectral (PS) methods.