非分裂完全匹配层边界存储时间域全波形反演

The forward-modeling wavefield storage or reconstruction is a key question in the time-domain full waveform inversion. The strategy of storage replaced by computation based on conventional splitting perfect matched layer (SPML) boundary conditions can effectively reduce the amount of storage. However, conventional SPML boundary conditions require a large number of variables, a large amount of memory, and complex programming. In this paper, an effective boundary storage strategy based on the complex frequency shifted non-splitting perfect matched layer (CFS-NPML) is proposed to reconstruct the forward-modeling wavefield to realize the time-domain full waveform inversion. According to our study, fewer variables in CFS-NPML are needed; the absorption effect is better than conventional SPML boundary conditions when grid points of the boundary absorption layer are less. So less storage capacity is needed than that of conventional SPML boundary conditions in the wavefield reconstruction process. Numerical experiments show that there is almost no difference between the forward-modeling wavefield and the reconstructed wavefield obtained with this storage strategy. The velocity obtained by the full waveform inversion with this storage strategy is consistent with that obtained by the conventional storage wavefield inversion. The wavefield reconstruction does not significantly increase the computer time consuming thanks to parallel computation introduction.