Azimuthally averaged horizontal velocities around the average supergranule outflow and inflow centers at solar latitude 40°. The measurements were obtained from LCT of granules in HMI intensity images. a) Horizontal velocities v_r and v_t around the average supergranule outflow center. The thin lines mark an estimate of the variability of the data as measured by dividing the 336 datasets into eight parts. For v_r, the 10σ level is shown, for v_t the 3σ level. b) As a), but around the average supergranule inflow center.