Inversion of time-domain airborne EM data with IP effect based on Pearson correlation constraints

Abstract

Due to the induced polarization (IP) effect, the sign reversal often occurs in time-domain airborne electromagnetic (AEM) data. The inversions that do not consider IP effect cannot recover the true umderground electrical structures. In view of the fact that there are many parameters of airborne induced polarization data in time domain, and the sensitivity difference between parameters is large, which brings challenges to the stability and accuracy of the inversion. In this paper, we propose an inversion mehtod for time-domain AEM data with IP effect based on the Pearson correlation constraints. This method uses the Pearson correlation coefficient in statistics to characterize the correlation between the resistivity and the chargeability and constructs the Pearson correlation constraints for inverting the objective function to reduce the non uniqueness of inversion. To verify the effectiveness of this method, we perform both Occam’s inversion and Pearson correlation constrained inversion on the synthetic data. The experiments show that the Pearson correlation constrained inverison is more accurate and stable than the Occam’s inversion. Finally, we carried out the inversion to a survey dataset with and without IP effect. The results show that the data misfit and the continuity of the inverted section are greatly improved when the IP effect is considered.