Some streamlines that pass next to the centre of the anticyclone (upper figure) and cyclone (lower figure) at t = 300 are plotted in 3D. The direction of the flow is given by the colours: the flow moves from the blue part to the red part. The cyclone is a downward flow, contrary to the upward anticyclonic flow. The vortices have a coherent structure over the whole height of the disc. The radial extent of this figure corresponds approximately to half of of Fig. 9: only the inner parts of the vortices are shown here.