论文标题
风暴潮建模作为在MPA-ocean中的本地时间步变的应用
Storm Surge Modeling as an Application of Local Time-stepping in MPAS-Ocean
论文作者
论文摘要
本文介绍了跨尺度 - 海洋（MPAS-O）的预测模型中局部时间步变（LTS）方案的第一个科学应用。我们在单层的全球海洋模型中使用了LTS计划，该模型预测了桑迪飓风期间美国东部海岸周围的风暴潮。使用的可变分辨率网格在MPAS-O中是前所未有的高分辨率，其中包含特拉华湾宽至125米的细胞。结果表明，特定的三阶LTS方案（LTS3）产生的海面高度（SSH）溶液与经典四阶段的四阶段Runge-kutta方法（RK4）产生的溶液具有可比的质量，并在同一网格上具有均匀的时间步长。此外，在最佳情况下，LTS3的速度高达35％，这表明LTS方案可在MPAS-O中可行，其计算成本的额外好处却大大降低。这些性能实验的结果向我们告知了LTS方案有效网格设计的要求。特别是，我们看到LT在给定的网格上有效地有效，重要的是要使用粗略的时间步，相对于使用精细的时步，通常至少1：5。
This paper presents the first scientific application of local time-stepping (LTS) schemes in the Model for Prediction Across Scales-Ocean (MPAS-O). We use LTS schemes in a single-layer, global ocean model that predicts the storm surge around the eastern coast of the United States during Hurricane Sandy. The variable-resolution meshes used are of unprecedentedly high resolution in MPAS-O, containing cells as small as 125 meters wide in Delaware Bay. It is shown that a particular, third-order LTS scheme (LTS3) produces sea-surface height (SSH) solutions that are of comparable quality to solutions produced by the classical four-stage, fourth-order Runge-Kutta method (RK4) with a uniform time step on the same meshes. Furthermore, LTS3 is up to 35% faster in the best cases, showing that LTS schemes are viable for use in MPAS-O with the added benefit of substantially less computational cost. The results of these performance experiments inform us of the requirements for efficient mesh design for LTS schemes. In particular, we see that for LTS to be efficient on a given mesh, it is important to have enough cells using the coarse time-step relative to those using the fine time-step, typically at least 1:5.
