Ask The Science Experts

What does Doppler radar mean and how is it different from other radar?

RADAR, an acronym for Radio Detection and Ranging, operates by transmitting a wave and recording the time it takes that wave to bounce off of an object and return to the source. Since we know the speed the transmitted wave is traveling, we can calculate the distance of the object.

Doppler radar operates on the same principle, but it also detects an objects motion by measuring the frequency shift between the outgoing wave and the returning wave. An object moving toward the radar would increase the returning wave’s frequency while an object moving away from the radar decreases the wave’s frequency. For weather purposes, this provides important information about the speed and direction of winds within thunderstorms.

Source: USA Today, Ask the Weather Experts. Posted by admin for the best selling toys of 2008 at Atomic Elephant Science & Toy Co.

One way would be for two people communicating wirelessly to start in a wide-open area and start walking until they could no longer see each other. Of course this is ridiculous. The way it’s usually done, by airports and such, is by looking at predetermined landmarks of known distances. Daytime visibility is defined as the distance in which is is possible to see and identify, with the naked eye, “a prominent dark object against the sky at the horizon.” Read the rest of this entry »