  In standard accretion discs, outward angular momentum transfer by viscous
forces is compensated by the inward motion of the accreting matter. However,
the vertical structure of real accretion discs leads to meridional circulation
with comparable amplitudes of poloidal velocities. Using thin-disc
approximation, we consider different regimes of disc accretion with different
vertical viscosity scalings. We show that, while gas-pressure-dominated discs
can easily have a midplane outflow, standard thin radiation-pressure-dominated
disc is normally moving inwards at all the heights. However, quasi-spherical
scaling for pressure ($p\propto \varpi^{-5/2}$) leads to a midplane outflow for
a very broad range of parameters. It particular, this may lead to a reversed,
outward heat advection in geometrically thick discs when the temperature
decreases rapidly enough with height. While the overall direction of heat
advection depends on the unknown details of vertical structure and viscosity
mechanisms, existence of the midplane counterflow in quasi-spherical flows is a
robust result weakly dependent on the parameters and the assumptions of the
model. Future models of thick radiatively inefficient flows should take
meridional circulation into account.
