Let's have a look at the flow of water in this model from the side. This diagram is represents a vertical movement of balls floating under the surface of the water.

This motion of the balls might seem plausible, but if you look at the diagram more closely, you can see that the water flows downward near the warm (outer) edge, and rises near the cold (inner) edge. That's right.

The flow of water is the reverse

of normal thermal convection.

The fact that the direction of the water flow is the reverse of a normal convection current is an extremely strange characteristic of the flow associated with the baroclinic instability.