Reduction to the pole at low latitudes by using the Taylor series iterative method

A Taylor series iterative (TSI) method is proposed to improve the stability and accuracy of reduction to the pole (RTP) at low latitudes. Firstly, the method constructs an approximate RTP operator of magnetic data at the geomagnetic equator based on the truncated Taylor series. By using the iterative method in wavenumber domain, a stable and high-accuracy algorithm is developed for RTP at the geomagnetic equator. Finally, combined with the reduction to the equator (RTE), the RTP factor of magnetic data at any latitude is achieved. The number of iterations is determined by the correlation coefficient between the RTP results and the analytic signal amplitude (ASA) of original anomaly, which reduce the impact of human choice. The method has the advantages of simple principle, quick calculation and less control parameters. The tests on both synthetic data and the real data located in Sulu Sea show that the proposed method gives a more stable and accurate RTP result than the other methods in the study.