对《基于离散余弦变换的磁位谱分析及磁异常导数计算方法》一文的评论

Comment on "Magnetic potential spectrum analysis and calculating method of magnetic anomaly derivatives based on discrete cosine transform"

被评论的论文(简称原文)中应用离散余弦变换(DCT法)计算磁异常导数,并与离散Fourier变换法(DFT法)计算结果进行对比,得到"DCT法明显优于DFT法"的结论.我们对原文进行了验证.原文磁异常导数波数响应计算的错误导致DFT法计算的错误,最终导致结论的错误.原文相关两篇论文中应用DCT法分别进行重力异常的导数换算和重力异常的向上延拓,也存在同样的错误.

The derivatives of the magnetic anomaly are calculated by the discrete cosine transform（DCT method） in the commented paper,and the results are compared with the derivatives calculated by the discrete Fourier transform（DFT method）.The main conclusion is that the DCT method is obviously superior to the DFT method.However,according to our test,we find that erroneous wave number response of the derivatives of magnetic anomaly results in wrong calculation of the DFT method in the commented paper.Consequently,the authors draw an improper conclusion.Moreover,the derivatives and the upward continuation of the gravity anomaly are calculated by the DCT method and the DFT method in the related other two papers,respectively.The same mistakes exist in the papers.