Adaptive 9-point frequency-domain finite difference scheme for wavefield modeling of 2D acoustic wave equation

Abstract

The frequency-domain finite difference (FDFD) method is a useful tool for wavefield modeling of wave equations. To further improve the accuracy and efficiency of wavefield modeling with the FDFD method, we propose a new 9-point FDFD scheme for wavefield modeling of the 2D acoustic wave equation, which has both the accuracy of optimal 25-point FDFD schemes and the efficiency of optimal 9-point FDFD schemes. In the proposed scheme, the FDFD coefficients are not only related to the ratio of the spatial grid size in the x-direction to the spatial grid size in the z-direction, but also related to the ratio of the spatial grid size in the x-direction to wavelength. By using the plane wave solution and lookup table technique, the FDFD coefficients of the proposed scheme can be efficiently determined. Moreover, numerical results show that the proposed scheme is as accurate as the optimal general 25-point scheme and costs comparable computational time and computer memory compared with the optimal average-derivative 9-point scheme.