This study conducts an analysis of the polar numerical noise in the barotropic shallow‐water version of the Grid‐point Atmospheric Model of IAP LASG (GAMIL‐SW) and provides a good solution to the problem. GAMIL‐SW suffers from numerical noise in the polar region in some ideal test cases, which is likely to be detrimental to the full physical model. The noise is suspected to be related to the nonlinear advection term in the momentum equation. Thus, a new shallow‐water model with a vector‐invariant form of the momentum equation is developed on the latitude‐longitude grid to analyze the polar noise. It is found that the version with meridional wind component staggered on the pole is free from noise, while the version with zonal wind component staggered on the pole is still contaminated. By redefining the polar relative vorticity, the polar noise is eliminated in the latter version, and the global conservation properties are maintained. In addition, the test cases demonstrate that the new shallow‐water model maintains the properties of the original GAMIL‐SW with respect to numerical accuracy and computational stability. This study helps to identify appropriate governing equations to further develop the next generation of GAMIL dynamical core.

中文翻译：

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纬度—经度网格浅水模型内极地数值噪声的分析与解决

这项研究对IAP LASG网格点大气模型（GAMIL-SW）的正压浅水版本中的极地数值噪声进行了分析，并为该问题提供了很好的解决方案。在某些理想的测试案例中，GAMIL-SW在极地区域会受到数值噪声的影响，这可能对整个物理模型有害。怀疑噪声与动量方程中的非线性对流项有关。因此，在纬度—经度网格上开发了一个具有矢量不变形式动量方程的新浅水模型，以分析极性噪声。发现在子极上交错有子午风分量的版本没有噪音，而在子极上交错有子午风分量的版本仍然受到污染。通过重新定义极地相对涡度，后者消除了极性噪声，并保持了整体守恒特性。此外，测试案例表明，新的浅水模型在数值精度和计算稳定性方面保持了原始GAMIL-SW的特性。这项研究有助于确定合适的控制方程式，以进一步开发下一代GAMIL动态核心。