摘要
The numerical dispersion and computational cost are high for conventional Taylor series expansion staggered-grid finite-difference forward modeling owing to the high frequency of the wavelets and the large grid intervals. In this study, the cosine-modulated binomial window function （CMBWF）-based staggered-grid finite-difference method is proposed. Two new parameters, the modulated time and modulated range are used in the new window function and by adjusting these two parameters we obtain different characteristics of the main and side lobes of the amplitude response. Numerical dispersion analysis and elastic wavefield forward modeling suggests that the CMBWF method is more precise and less computationally costly than the conventional Taylor series expansion staggered-grid finite-difference method.
交错网格有限差分方法被广泛地应用于地震波场正演模拟,但是震源主频升高和网格间距增大会带来计算机时级数增加和严重的数值频散现象,甚至这种频散会使目标成像或反演结果呈现假象。为了降低频散和提高效率,我们提出余弦修正二项式窗函数(CMBWF)优化交错网格有限差分正演方法,在修正过程中引入修正范围和修正次数参数。通过调节修正参数可以改善二项式窗的主瓣宽度和旁瓣衰减,不仅实现了更大的截断谱范围,而且保证了截断的精度。数值模拟表明,基于余弦修正二项式窗方法较泰勒级数展开方法有着更高的模拟精度,可以更好的控制数值频散和计算效率。
基金
supported by the National Major Research Equipment Development Projects(No.ZDYZ2012-1-02-04)
the National Natural Science Foundation of China(No.41474106)
