The
tomographic simulation also produced two reversals, the
first of which is shown here (zoom to enlarge). On the left
(a & c), the dipole moment (normalized by Earth -radius
cubed) and the true-dipole path are plotted versus time
step (100 yr), each fifth step between 1680 and 1725 corresponding
to letters F-O. On the right are plotted (b) axial and inclined
dipole intensity, total-field intensity (left axis) and
reversal angle (right axis) and (d) VGP path for the site
indicated by the star. The 2.5 kyr duration, as defined
by the dipole intensity, is similar to the previous example,
but the non-axial-dipole field is much more active (see
next figure), giving rise to greater variation in transition
signature over the globe. The prominent excursion in direction
(H-I-J-K) after the initial switch in polarity reminds one
of the Steens Mountain reversal record. (Click
to enlarge)
The
onset of the reversal was marked by the rapid growth of
two enormous nondipole-field flux patches of opposite sign.
These reversed the field at high northern latitudes, and
temporarily as well at equatorial latitudes between longitudes
90 and 300 east.
