NTRTP: a new reduction to the pole method at low latitudes via a nonlinear thresholding

Abstract

We present a stable reduction to the pole (RTP) approach using a nonlinear threshold method with better RTP performance for magnetic data at lowlatitudes. In the newnonlinear thresholding RTP (NTRTP)method, the routine RTP operator is divided into two parts (the real part and imaginary part), which are modified respectively based on a nonlinear threshold to suppress the large amplitude linked to instability. It is tested on a couple of synthetic data (one is modeled at magnetic equator) and a field case from central Brazil (with a low inclination of −5°) and comparedwith two existing RTP methods. The proposedmethod in this study performs stable and estimates more accurate amplitudes for RTP field than the existing methods used in this study.