a) Mean entropy gradient profile and zoom in the region where the entropy gradient changes sign. Entropy gradients are plotted in erg g^-1 K^-1 cm^-1. b) Radial velocity on a spherical shell near the top of the convection zone (0.96   R_⊙). Dark colors represent the downflows, while bright-yellow colors denote the upflows. c) rms velocities profiles at the interface between radiative and convective zones. The four vertical bars label the base of the convection zone (where the entropy gradient changes sign), the penetration depth of meridional circulation, the overshooting depth of convective motions, and the shear depth where differential rotation vanishes.