What determines the velocity within a three-body scatterer spike?

The velocity within a three-body scatterer spike is determined primarily by the net motion of hail in the core. This phenomenon occurs when large hailstones or other scatterers interact with radar waves, causing the radar to detect a spike in returns that reflects the movement of the scatterers. The speed and direction of the hail's descent or upward motion during severe weather events, which can be influenced by factors such as updrafts or downdrafts within a storm, play a crucial role in determining the observed velocity.

While the height of the hail core may provide context about storm structure, and the distance from the radar can affect the signal's strength, it is the actual motion of the hailstones themselves that dictates the velocity measurement in this context. Similarly, the intensity of radar waves is related to signal strength and not directly to the measurement of velocity. Thus, the net motion of hail is the key factor that influences the data observed in a three-body scatterer spike.