  The observed convective flows on the photosphere (e.g., supergranulation,
granulation) play a key role in the Babcock-Leighton (BL) process to generate
large-scale polar fields from sunspots fields. In most surface flux transport
(SFT) and BL dynamo models, the dispersal and migration of surface fields is
modeled as an effective turbulent diffusion. Recent SFT models have
incorporated explicit, realistic convective flows in order to improve the
fidelity of convective transport but, to our knowledge, this has not yet been
implemented in previous BL models. Since most Flux-Transport (FT)/BL models are
axisymmetric, they do not have the capacity to include such flows. We present
the first kinematic 3D FT/BL model to explicitly incorporate realistic
convective flows based on solar observations. Though we describe a means to
generalize these flows to 3D, we find that the kinematic small-scale dynamo
action they produce disrupts the operation of the cyclic dynamo. Cyclic
solution is found by limiting the convective flow to act only on the vertical
radial component of the magnetic field. The results obtained are generally in
good agreement with the observed surface flux evolution and with non-convective
models that have a turbulent diffusivity on the order of $3 \times 10^{12}$
cm$^2$ s$^{-1}$ (300 km$^2$ s$^{-1}$). However, we find that the use of a
turbulent diffusivity underestimates the dynamo efficiency, producing weaker
mean fields and shorter cycle than in the convective models. Also, the
convective models exhibit mixed polarity bands in the polar regions that have
no counterpart in solar observations. Also, the explicitly computed turbulent
electromotive force (emf) bears little resemblance to a diffusive flux. We also
find that the poleward migration speed of poloidal flux is determined mainly by
the meridional flow and the vertical diffusion.

Solar and Stellar Astrophysics