An improved technique for reduction to the pole at low latitudes

Reduction to the pole at low latitudes based on a Wiener filtering approach has been improved by introducing a deterministic noise model. It is assumed that the noise power is a fixed fraction of the signal power. This allows the method to be fully automated. Further improvement is obtained by requiring the reduced‐to‐the‐pole field to map into the observed field when projected to the geomagnetic latitude of the observed field. This is done by …