  We address the question whether the properties of the observed latitude-time
diagram of sunspot occurence (the butterfly diagram) provide evidence for the
operation of a flux-transport dynamo, which explains the migration of the
sunspot zones and the period of the solar cycle in terms of a deep equatorward
meridional flow. We show that the properties of the butterfly diagram are
equally well reproduced by a conventional dynamo model with migrating dynamo
waves, but without transport of magnetic flux by a flow. These properties seem
to be generic for an oscillatory and migratory field of dipole parity and thus
do not permit an observational distinction between different dynamo approaches.

Astrophysics