An empirical orthogonal function reanalysis of the northern polar external and induced magnetic field during solar cycle 23

Shore, R. M., Freeman, M. P., and Gjerloev, J. W. (2018) An empirical orthogonal function reanalysis of the northern polar external and induced magnetic field during solar cycle 23, J. Geophys. Res.: Spaces Phys., 123, 781–795, doi.org/10.1002/2017JA024420 (pdf)