How does a Doppler radar work?
Similar to a conventional radar signal is emitted from a rotating antenna. When this signal now encounters a precipitation zone, depending on the density of the precipitation zone reflects more or fewer signals and registered by the antenna. The intensity of the reflected signal are even conclusions about the type and intensity of precipitation and you can even distinguish between drizzle, rain, hail and snow. From the time delay until the arrival of the echo, the distance to the respective radar system calculates. If now the data has more of these radar antennas, they yield a very accurate picture of the current Precipitate obtained.