Average isoplanatic angle without AO correction (black), with a ground-layer AO that corrects turbulence up to 500 m altitude (green), a two mirror MCAO (red) and a three mirror MCAO (blue). The conjugation heights correspond to the center and to the upper limit of the boundary layer (see Table 4). We consider the subset of profiles with best isoplanatic angles: the x-axis indicates the percentage of profiles considered.