Exact local refinement using Fourier interpolation for nonuniformgrid modeling  

作　　者：JinHai Zhang ZhenXing Yao 

机构地区：[1]Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences

出　　处：《Earth and Planetary Physics》2017年第1期58-62,共5页地球与行星物理（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No.41130418);the National Major Project of China (under grant 2017ZX05008-007);supports from the Youth Innovation Promotion Association CAS (2012054);Foundation for Excellent Member of the Youth Innovation Promotion Association (2016)

摘　　要：Numerical solver using a uniform grid is popular due to its simplicity and low computational cost, but would be unfeasible in the presence of tiny structures in large-scale media. It is necessary to use a nonuniform grid, where upsampling the wavefield from the coarse grid to the fine grid is essential for reducing artifacts. In this paper, we suggest a local refinement scheme using the Fourier interpolation, which is superior to traditional interpolation methods since it is theoretically exact if the input wavefield is band limited.Traditional interpolation methods would fail at high upsampling ratios(say 50); in contrast, our scheme still works well in the same situations, and the upsampling ratio can be any positive integer. A high upsampling ratio allows us to greatly reduce the computational burden and memory demand in the presence of tiny structures and large-scale models, especially for 3D cases.Numerical solver using a uniform grid is popular due to its simplicity and low computational cost, but would be unfeasible inthe presence of tiny structures in large-scale media. It is necessary to use a nonuniform grid, where upsampling the wavefield from thecoarse grid to the fine grid is essential for reducing artifacts. In this paper, we suggest a local refinement scheme using the Fourierinterpolation, which is superior to traditional interpolation methods since it is theoretically exact if the input wavefield is band limited.Traditional interpolation methods would fail at high upsampling ratios （say 50）; in contrast, our scheme still works well in the samesituations, and the upsampling ratio can be any positive integer. A high upsampling ratio allows us to greatly reduce the computationalburden and memory demand in the presence of tiny structures and large-scale models, especially for 3D cases.

关 键 词：local refinement varying grid tiny structures fourier interpolation nonuniform grid 

分 类 号：O241[理学—计算数学]