引力位是地球自由振荡数值模拟中不可或缺的一部分，也是重力异常研究中需要计算的对象。由于引力位满足无界的泊松-拉普拉斯方程，其在无穷远边界处为零，这对数值模拟造成了困扰。针对此，采用无限元-谱元混合法，直接对无穷远边界进行拟合，不再对边界条件做近似；同时考虑到三维地球模型计算效率问题，采用2.5维控制方程；最后，通过数值试验，验证了方法的准确性。
Gravitational potential is an inseparable part of the earth’s free oscillation simulation. It is also the object of calculation in the study of gravity anomalies. Since the gravitational potential satisfies the unbounded Poisson-Laplace equation, which is zero at infinity, this is frustrating for numerical simulations. The purpose of numerical simulation is usually achieved by limiting the solution domain and approximating its boundary conditions. We attempt to use the infinite-spectral hybrid method to fit the infinity boundary directly and no longer approximate the boundary conditions. Considering the computational efficiency of the 3D Earth model, this study uses a 2.5-dimensional governing equation. Finally, numerical experiments verify the factual accuracy of this method.
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