  The outer surface layers of the sun show a clear deceleration at low
latitudes. This is generally thought to be the result of a strong dominance of
vertical turbulent motions associated with strong downdrafts. This strong
negative radial shear should not only contribute to amplifying the toroidal
field locally and to expelling magnetic helicity, but it may also be
responsible for producing a strong prograde pattern speed in the
supergranulation layer. Using simulations of rotating stratified convection in
cartesian boxes located at low latitudes around the equator it is shown that in
the surface layers patterns move in the prograde direction on top of a
retrograde mean background flow. These patterns may also be associated with
magnetic tracers and even sunspot proper motions that are known to be prograde
relative to the much slower surface plasma.
