Radar Velocity Question

[jgf]

so I understand that in a basic sense, when i look at the super res velocity in radarscope, i am seeing the magnitude of the vector component of wind parallel to the radius from the radar location - at the altitude of the return

but when there is no rain.., what is actually being measured?

here is KOKX (Upton NY) saturday august 28 at about 11:25am 

it's a bright sunny day - for the most part, as indicated by the reflectivity

the velocity plot is indicating relative movement with respect to the radar

my question is: relative movement of what?

 

 

[isohume]

When the radar is in high-sensitivity mode (ie: VCP32/VCP31), it rotates slower which allows it's pulses to pick up on smaller scale features like dust and small particulates. The motion of these tiny elements is what base velocity is detecting and measuring wrt to the radar.