Articles | Volume 6, issue 2
Research article
17 Oct 2017
Research article |  | 17 Oct 2017

U.S. Geological Survey experience with the residual absolutes method

E. William Worthington and Jürgen Matzka

Abstract. The U.S. Geological Survey (USGS) Geomagnetism Program has developed and tested the residual method of absolutes, with the assistance of the Danish Technical University's (DTU) Geomagnetism Program. Three years of testing were performed at College Magnetic Observatory (CMO), Fairbanks, Alaska, to compare the residual method with the null method. Results show that the two methods compare very well with each other and both sets of baseline data were used to process the 2015 definitive data. The residual method will be implemented at the other USGS high-latitude geomagnetic observatories in the summer of 2017 and 2018.

Short summary
We have compared two methods of performing Absolute observations of the Earth's magnetic field. The newer, Residual method was evaluated for use at USGS geomagnetic observatories and compared with measurements using the traditional Null method. A mathematical outline of the Residual method is presented, including more precise conversions of the Declination angles to nanoTeslas (nT). Results show that the Residual method is better than the Null method, especially at high latitude.