Final answer:
During vortex breakdown, a downdraft may develop in the eye of the storm, which is the center of the tornado vortex. The winds are usually weaker at the center due to the inverse relationship between tangential velocity and the radius of curvature.
Step-by-step explanation:
To answer the question about what occurs in the center of a tornado vortex during vortex breakdown, it is essential to understand the dynamics of tornado formation and structure. A tornado is a rapidly spinning column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. The mechanics of tornadoes are closely linked to rotational motion and angular momentum, similar to how an ice skater pulls their arms in to spin faster.
The eye of the storm, or the center of rotation, is where the winds can be weaker compared to the outer edges of the tornado. This is because the tangential velocity is inversely proportional to the radius of curvature. As one approaches the center, the radius decreases, causing the tangential velocity, and therefore the wind speed, to decrease as well. Thus, a downdraft may indeed develop at the center, but the options regarding supersaturation or hydrostatic balance are not straightforward conclusions within the typical descriptions of tornado dynamics.
From observations and the fundamental physics of tornadoes, the GRASP CHECK suggests option (b): 'The eye of the storm is the center of rotation. Winds are weaker at the eye of a tornado because tangential velocity is inversely proportional to radius of curvature.' This explanation aligns with the observed structure of tornadoes and the principle of conservation of angular momentum evident in the behavior of rotating bodies.