This paper presents the new version of the operational code used at the Tsunami Warning Centers in French Polynesia and in mainland France. This nested multigrid code solves either the nonlinear shallow water or the weakly nonlinear Boussinesq equations in a spherical or Cartesian coordinates system. The objective is to simulate the propagation of tsunamis both in the context of tsunami early warning and in the context of research. The originality of this code is to simulate the tsunami propagation through a series of nested grids in which the numerical scheme is specified by the user. Three standard finite-difference methods and two finite volume schemes are available to take into account the dispersive nature of waves or to capture flow discontinuities. The performance of the five numerical schemes has been assessed through idealized 1D and 2D test cases. The convergence rate with grid refinement is evaluated for three of these tests. Diffusion and dispersion of the five schemes are evaluated through the 1D far-field propagation in a channel of constant depth. Finally, two-dimensional simulations of the 2011 Japanese tsunami are performed considering a homogeneous tectonic source. Coastal inundation is simulated in the bay of Kamaishi where run-up heights reached 10 m. The ability of the five schemes to propagate trans-Pacific tsunamis is evaluated through comparisons of time series between simulations and observations at DART buoys. In the context of tsunami early warning, numerical results show that standard finite-difference methods reproduce most of the observed time gauges and that numerical errors associated to these schemes are acceptable.

本文介绍了法属波利尼西亚和法国大陆海啸预警中心使用的新版操作规范。这种嵌套的多网格代码可以求解球面或笛卡尔坐标系中的非线性浅水或弱非线性Boussinesq方程。目的是在海啸预警和研究范围内模拟海啸的传播。此代码的独创性是模拟海啸在一系列嵌套网格中的传播，在嵌套网格中用户指定了数字方案。可以使用三种标准的有限差分方法和两种有限的体积方案来考虑波浪的色散特性或捕获流动不连续性。通过理想化的1D和2D测试用例评估了这五个数值方案的性能。对其中三个测试评估了网格细化的收敛速度。通过在恒定深度的通道中的一维远场传播来评估五种方案的扩散和色散。最后，在考虑均质构造源的情况下，对2011年日本海啸进行了二维模拟。在龟裂湾模拟了沿海淹没，其上升高度达到10 m。通过比较DART浮标上模拟和观测值之间的时间序列，评估了五种方案传播跨太平洋海啸的能力。在海啸预警的背景下，