Question on 2 nexrad products: Radial Velocity and Wind Prof

[Pileus]

Radial Velocity and Wind Profile values are important when determining
how much veering and rotation there is in a TS. Am I correct that both
of these observations are made only from the radar site? Help me if I
am wrong but what good is it to measure conditions directly above the
reporting station instead of 100 miles out where a meso might be evolvng.

[wxman57]

There's a very simple reason for that - the Earth is a sphere. As such, the farther out the radar beam travels (in a straight line), the higher above the ground the beam will be. By the time it's out there at 100 miles, the lowest that the beam can see is perhaps 10,000 ft. So the radar could not profile the lower atmosphere away from the radar site itself. Also, you have to contend with angular dispersion - the beam spreads out as it travels away from the radar site. That means less radar energy per unit area and less reliable profile data.