Ka-Band Doppler radar Metek MIRA-35 fixed NF

A cloud radar MIRA36 designed by METEK GmbH has been operating at CIAO since March 2009. In 2022 the radar was upgraded to a MIRA35. It is a mono-static pulsed Ka-Band Doppler radar for unattended long term observation of clouds properties. In the configuration operative at CIAO, linear polarized pulses are transmitted in the atmosphere, while co- and cross polarized backscattered signals are received simultaneously to detect the profiles of the Doppler spectrum and related moments, such as the reflectivity factor and Linear Depolarization Ratio (LDR). The reflectivity is used to determine the density of cloud particles, while LDR helps to identify hydrometeors’ shape and type.

The radar has a 1 m diameter antenna emitting microwave pulses at 35.5 GHz, with a peak power of 30 kW, duration of 200 ns and repetition rate of 5 KHz. The antenna beam width is 0.6° x 0.6°, the antenna gain is 49 dBi, while the radar sensitivity is -44 dBZ (-53dbZ) at 5 km 0.1 sec (10 sec) time resolution. The Doppler velocity resolution is better than 0.05 m/s. The LDR accuracy is within +/- 2.0 dB, while the receiver calibration accuracy is within +/- 1 dB.

A clutter fence around the antenna strongly suppresses the ground clutter echo. The radar is also equipped with a 3D scanning unit and it has been the first Ka-band radar in Europe capable of performing a 3D scanning of the atmosphere in order to derive wind speeds and hydrometeors’ size distribution and shape.

Radar profiles typically measured at CIAO have a vertical resolution of 30 m and a temporal resolution of 10 seconds. The typical measurement range is from 100 m to about 15 km, but during scanning scenarios the maximum range can be extended along the off-zenith line-of-sight.