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Types of weather radar

Figure 1: Smart-R (Doppler radar On Wheels, DOW) observes a sandstorm

Figure 1: Smart-R (Doppler radar On Wheels, DOW) observes a sandstorm

Types of weather radar

Weather radar can generally be divided into radar sets with a fixed location and mobile radar sets, whereby here the fine difference between mobile and transportable must be considered. Mobile systems are only those devices that are in operation during a movement, for example, weather radar in an airplane or satellite. Even highly transportable radars, such as those used in the USA to monitor tornadoes, are not mobile, because they have a fixed location during operation.

Weather radars are usually highly specialized to perform a precisely defined task. They use a frequency range between 2.7 and 100 GHz. Their transmitted power can vary between a few tens of kilowatts and one megawatt, depending on the task. This power is often generated by either a magnetron or a klystron. Semiconductor transmitters are also possible, but because of the necessary pulse compression (especially because of their time sidelobes), they usually have a worse accuracy of the measurement results. The polarization is often switchable between linear horizontal or linear vertical or both polarizations are used simultaneously. Then the term STAR Modus (Simultaneous Transmission And Reception) is often used. The receivers of weather radars require a dynamic range of usually more than 100 dB. This is technically realized by using several receivers with different sensitivity in parallel. If one receiver is saturated, the echo signal from the less sensitive receiver is used.

There are following weather radar types depending on the task: