Citation: | Liu, Y. S., Xu, T., Wang, Y. H., Teng, J. W., Badal, J., and Lan, H. Q. (2019). An efficient source wavefield reconstruction scheme using single boundary layer values for the spectral element method. Earth Planet. Phys., 3(4), 342–357.. doi: 10.26464/epp2019035 |
In the adjoint-state method, the forward-propagated source wavefield and the backward-propagated receiver wavefield must be available simultaneously either for seismic imaging in migration or for gradient calculation in inversion. A feasible way to avoid the excessive storage demand is to reconstruct the source wavefield backward in time by storing the entire history of the wavefield in perfectly matched layers. In this paper, we make full use of the elementwise global property of the Laplace operator of the spectral element method (SEM) and propose an efficient source wavefield reconstruction method at the cost of storing the wavefield history only at single boundary layer nodes. Numerical experiments indicate that the accuracy of the proposed method is identical to that of the conventional method and is independent of the order of the Lagrange polynomials, the element type, and the temporal discretization method. In contrast, the memory-saving ratios of the conventional method versus our method is at least