An improved regularized downward continuation of potential field data

• We proposed an improved regularization operator for downward continuation of potential field data.
• The new operator is based on the characterization of the potential field spectrum.
• The regularization parameter is choice by the cutoff wavenumber.
• The proposed operator can produce more stable and precise results than the Tikhonov operator.

Downward continuation of potential field data plays an important role in interpretation of gravity and magnetic data. For its inherent instability, many methods have been presented to downward continue stably and precisely. In this manuscript, we propose an improved regularization operator for downward continuation of potential field data. First, we simply define a special wavenumber named the cutoff wavenumber to divide the potential field spectrum into the signal part and the noise part based on the radially averaged power spectrum of potential field data. Next, we use the conventional downward continuation operator to downward continue the signal and the Tikhonov regularization operator to suppress the noise. Moreover, the parameters of the improved operator are defined by the cutoff wavenumber which has an obvious physical significance. The improved operator can not only eliminate the influence of the high-wavenumber noise but also avoid the attenuation of the signal. Experiments through synthetic gravity and real aeromagnetic data show that the downward continuation precision of the proposed operator is higher than the Tikhonov regularization operator.