A study of the calibration of the new generation of millimeter wavelength cloud radar (HMBQ) and its detection capability

An 8.6 mm wave-length cloud radar with Doppler and polarization capabilities in China is introduced, including its design, parameters, calibrations and applications in measuring clouds. This study is threefold: to expatiate on the method how to test hardware parameters of the transmitter and the receiver with external instruments, to test the calibration and results of the dynamic range about the radar echo power, and to research the capability of the millimeter wavelength cloud radar in observations via both theoretical computation and comparative study of practical data with the other two SA weather radars (10 cm wave-length) in the field experiment. The main conclusions to be drawn from this paper are the following: （1）the precision of the radar parameters can generally satisfy observing and researching needs；（2）some technologies such as the coherence accumulation and the pulsating compression are applied to this radar, which enables its minimum detectable echo intensity at 10 km away from radar to arrive at about -40 dBz;（3）the echo intensity calibration of the millimeterwavelength cloud radar is almost in agreement with that of the SA radar, though either one has its respective advantages and shortcomings. For example，the millimeterwavelength cloud radar has higher sensitivity than SA radar does for the non or weak precipitating cloud, and the SA radar has less attenuation than the millimeterwavelength cloud radar for the severe precipitating cloud or the cloud with high water content. Hence, in many cases, we need to first make decision whether we should use cloud radar only or should combine other equipments as well.