What does Base Reflectivity mean in regards to Doppler Radar images?

Question

I'm looking at the NWS site www.weather.gov

Answer 1

An NWS Doppler radar emits beams of radiation which particles such as precipitation reflect back to the radar (thus called echoes - similar with how your voice echoes off objects and back to you). Scans can be done at elevation angles (angles above the horizontal plane) between .5° and 19.5°. Being the lowest scan - closest to ground - the .5° scan tends to best represent the intensity of precipitation reaching ground and is called the "base reflectivity" (analogous to how an object's base is at its bottom). Higher scans can avoid ground interference and clutter at some locations, but also detect more of the large droplets/crystals in the clouds which won't reach the ground.

Answer 2

doppler measures a reflective phase shift due to a distance change. 1. something is moving.

Reflectivity measures amounts of particulate matter including water molocules from a viewpoint above the earth. 2.static view of things in the atmosphere.

There is a Delta factor that is included in doppler that turns a picture into a movie.

Answer 3

absolute signal stregth of the returned (reflected) pulse. aside from that phase shift is check to determine speed to/from the radar (doppler)

Answer 4

the percentage of returned radar is based on the surface material.

Answer 5

its a reflective image...hence the radar...