Auroral Occurrences in Norwegian Archives
Occurrences of aurorae back to AD 1100, described in Norwegian archives are compared with the auroral zone estimated in the light of secular variations in the geomagnetic field. Descriptions of auroral occurrence are consistent with the estimated auroral zone back to the 13th Century. Beyond that time a discrepancy in timing between documents and estimates is found. Although auroral documents tell us that aurorae were more common in Greenland than in Norway from AD 1100 to 1250, estimated auroral zone suggests that the time interval when aurorae might be absent in Norway should be from AD 1250 to 1350. This discrepancy is probably due to uncertainty in age determination of either auroral documents or geomagnetic secular variations, particularly in the precession of the dipole axis, or both of them.
- Journal of geomagnetism and geoelectricity
Journal of geomagnetism and geoelectricity 47(4), 353-359, 1995-04
Society of Geomagnetism and Earth, Planetary and Space Sciences