  Mursula et al. [2011] (MTL11) suggest that there is a 22-year variation in
solar wind activity that coupled with the variation in heliographic latitude of
the Earth during the year, gives rise to an apparent semiannual variation of
geomagnetic activity in averages obtained over several solar cycles. They
conclude that the observed semiannual variation is seriously overestimated and
is largely an artifact of this inferred 22-year variation. We show: (1) that
there is no systematically alternating annual variation of geomagnetic activity
or of the solar driver, changing with the polarity of the solar polar fields,
(2) that the universal time variation of geomagnetic activity at all times have
the characteristic imprint of the equinoctial hypothesis rather than that of
the axial hypothesis required by the suggestion of MTL11, and (3) that the
semiannual variation is not an artifact, is not overestimated, and does not
need revision.
