Weather radars are used to measure the location and intensity of precipitation – including rain, snow and hail
The wavelength of the pulse depends on the size of the particles being measured. The NCAS X-band radar operates at a frequency of 9.4 Ghz, which is equivalent to a wavelength of 3cm, useful for detecting small particles with a high degree of sensitivity. Under certain conditions, and in the absence of precipitation, the radar is sometimes able to detect insects, which are known as clear-air echoes. The radar also measures the velocity of the targets through the Doppler effect.
Scientists have been developing weather radar for over 50 years. Soon after radar was developed for detecting aircraft in the 1930s, scientists realised it could be used to identify the location and intensity of rain droplets too.