Differential reduction to the pole

Due to the dipolar nature of the geomagnetic field, magnetic anomalies located anywhere other than at the magnetic poles are asymmetric even when the magnetic source distribution is symmetrical. This complicates interpretation. Pole reduction (RTP) takes the anomaly, as measured at any latitude, and transforms it into that which would have been measured if the body had been laid at the magnetic pole i.e. the area where the field inclination is vertical and the anomalies from symmetrical bodies are symmetrical. The algorithm is usually applied in the frequency domain which has the advantage of being computationally fast, but the disadvantage of restricting the application of the algorithm to regions possessed of constant geomagnetic inclination and declination. Various frequency domain algorithms have been devised to solve this problem, but all have problems of one form or another. A simple algorithm for RTP is suggested here that employs a Taylor series expansion in the space domain (other work has used the Taylor series expansion approach in the frequency domain). The algorithm is demonstrated on synthetic data and on aeromagnetic data from the Northern Territory, Australia.