How do you find distant objects in the dark? use Radar, short for radio detection and ranging.
The Radar sends out a wave that bounces off the target and comes back. A built-in signal amplifier allows it to "see" weak signals. It is used in many different places.Barry's Response
- Good description of the equipment, similar to that used for the US national radar weather
service, U. This will do.
Weather surveillance radar, as we also know it, locates falling precipitation, and we can loop (animate) it to track the storm's advection (motion across the region.)
Doppler radar is even more fun, originally continuous wave Doppler radar became the standard for meteorology, and now we commonly use the pulse-Doppler radar to detect the location of the precipitation and computes the radial component of its velocity.
Sophisticated software handles the complicated mathematics involved in converting the returned electrical signals into meaningful data. We normally concern ourselves with reflectivity, normally expressed in dBZ. This dimensionless logarithm maps to a precipitation rate, depending on the type of precipitation.
The Position Plan indicator, shows the imprint of the data read from a beam that swept a cone-shaped pattern above the radar station. The further from the station, the higher the elevation of the object reflecting the data. If several of these cones are used and put together with their points aligned, a (approximate) slice can be made across all of them to result in a (nearly) constant altitude position plan indicator, CAPPI for short.
This is one of the most technical areas of meteorology. Search
this site for more radar information now.