基于概率成像技术的低纬度磁异常化极方法

化极转换是磁异常解释的重要基础，为了克服在地磁纬度较低的地区尤其是磁赤道附近化极不稳定的问题，出现了多种化极方法．本文基于概率成像技术提出了一种等效物性的反演方法，实现对地下等效场源的反演成像，取得了对低纬度磁异常稳定化极的效果．化极反演中逐次对剩余异常进行反演成像，实现由概率模型到物性模型的复杂映射，避免了类似反演中需要大型方程组求解等问题，并将概率模型的构制、物性参数的反演和反演评价有机地集成到一起，加速了反演成像的进程，使反演成像速度与目前概率成像的计算速度达到可相比拟的程度．对理论模型和实际资料的计算表明，该方法对低纬度磁异常化极处理是稳定有效的，而且可以较好地压制噪声干扰，能够在噪声干扰条件下进行反演化极．

Stable reduction to the pole at low magnetic latitude by probability tomography

Reduction to the pole (RTP) has played a key role in the interpretation of magnetic anomalies. In order to overcome the unstableness of RTP at low magnetic latitude, there are varieties of methods of RTP. We propose a new method of inversion by probability tomography and that allows stable reconstruction of the RTP field with a high fidelity even at the magnetic equator. The inverse model for RTP calculation consists of a set of juxtaposed equivalent prisms. This inversion carries on gradually by imagery of the residual magnetic anomalies and realizes the complexity mapping from the probabilistic model to the geophysical model under the condition of tomography. The processing of inversion does not need to solve linear algebraic equation system. The construction of probabilistic model, inversion for physical properties and appraisal can be organically integrated together to speed up the process of inversion，so that the speed of inverse calculation can be compared with the probability tomography. The computations of model and practical field data demonstrate the effectiveness of the method that the equivalent source construction offers a stable means for reducing a set of magnetic data to the pole at the equator even with the noise.