  We propose a solar dynamo model distributed in the bulk of the convection
zone with the toroidal magnetic field the flux concentrated in the near-surface
layer. We show that if the boundary conditions at the top of the dynamo region
allow the large-scale toroidal magnetic fields to penetrate closer to the
surface, then the pattern of the modeled butterfly diagram for the toroidal
magnetic fields in the upper part of the convection zone is formed by the
surface rotational shear layer. The model is in agreement with observed
properties of the magnetic solar cycle.
