中文摘要：

由于实际工作中测量的位场数据存在混叠效应,并且这些观测数据具有多源性、非线性和非稳态性的特点,如何从其中提取研究对象所产生的异常信息是位场数据处理中的关键环节.二维经验模态分解（Bidimensional Empirical Mode Decomposition,BEMD）在处理非线性、非平稳信号方面具有明显的优势,且具有分解的自适应性,实现了对信号的多尺度分解.文中采用BEMD方法首先对模型试验中带噪声的重力数据进行分解,得到各级固有模态函数和剩余分量,去掉一个或多个固有模态函数实现初步去噪,或结合小波阈值实现准确、圆滑去噪;再次,对三峡地区的布格重力异常进行了多尺度分解,并且利用径向对数功率谱分析方法估计了各级模态函数所反映的地下场源似深度,定性或半定量地解释了不同深度下的场源产生的异常,较好地揭示了场源赋存的地质信息,对上述分解得到的各分量进行组合叠加,重构出局部异常和区域异常,并且同常规分场方法进行了对比分析,结果表明BEMD方法能够准确、有效地实现位场的异常分离.

英文摘要：

Due to mix effect of potential field data we measured,and the data having multiple source,non-linear and non-stationary characters, how to extract the anomalies information of the study objects from those data plays a key role in the data processing of potential field.Bidimensional Empirical Mode Decomposition（BEMD）,which has obvious advantages in processing non-linear,non-stationary signal and also processing the data adaptively,has achieved the multi-scale decomposition of the signal.In this paper,firstly,the BEMD method is applied to gravity data with noise in the synthetic tests,we achieve the Bidimensional Intrinsic Mode Function（BIMF）at all levels and residue,we can finish the preliminary denoising by removing one or more BIMFs,or we can acquire the denoising results accurately and smoothly by combining with the method of wavelet threshold.Secondly,we also achieve the results of multi-scale decomposition of Bouguer gravity anomalies in the Three Gorges region,and estimate the approximate depth of the buried source by the radial logarithmic power spectrum of each BIMFs and residue,we obtain the qualitative or semi-quantitative explanation of anomalous field sources in different depths,which reveal the occurrence of geological information.Lastly,we can reconstruct the local and regional anomalies with BIMFs and residue.Compared with conventional methods,the BEMD method can realize the separation of potential field anomalies accurately and effectively.