Nonlinear Processes in Geophysics A nonlinear method of removing harmonic noise in geophysical data

Abstract. A nonlinear, adaptive method to remove the har-monic noise that commonly resides in geophysical data is proposed in this study. This filtering method is based on the ensemble empirical mode decomposition algorithm in con-junction with the logarithmic transform. We present a syn-thetic model study to investigate the capability of signal re-construction from the decomposed data, and compare the re-sults with those derived from other 2-D adaptive filters. Ap-plications to the real seismic data acquired by using an ocean bottom seismograph and to a shot gather of the ground pene-trating radar demonstrate the robustness of this method. Our work proposes a concept that instead of Fourier-based ap-proaches, the harmonic noise removal in geophysical data can be achieved effectively by using an alternative nonlinear adaptive data analysis method, which has been applied ex-tensively in other scientific studies.