位场向下延拓是重、磁处理和解释的常用方法,但其不稳定性限制了其在资料处理及反演中的应用.本文基于补偿圆滑滤波思想以及空间域向下延拓迭代法,通过逐次补偿的办法实现位场的稳定向下延拓.同时,在频率域空间给出了该下延方法的频率域响应因子,并讨论了其低通滤波特性,理论模型和实际位场资料试验表明该方法向下延拓稳定性具有较高的延拓精度.将其应用于重力密度界面反演中,改进反演的稳定性,实际莫霍界面反演表明下延因子具备实用性.%Downward continuation has commonly been used in gravity, magnetic data processing and interpretation, but the instability restricts its application in data processing and inversion. This paper introduces a method for downward continuation of potential field data, which is based on the ideas of iteration method for filtering of smooth compensation and downward continuation, and realizes more stable downward continuation by this compensation method. We also discuss the compensation method for the downward continuation in the frequency domain, and give the result of its frequency response. Furthermore, we analyze the filter characteristics of the downward continuation factor. The computations of model and practical data demonstrate the effect of the stability and long downward continuation distance, and also have high accuracy downward continuation results. Meanwhile, we substitute this stable downward continuation for the intrinsic operator in the iterative procedure of Parker-Oldenburg method and strengthen the stability of inversion. The procedure of density interface inversion has been examined effectively by computing Moho depth as a practical geological example.
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