Development of a new C-band polarimetric Doppler weather radar in Japan

Communications Research Laboratory (CRL) has developed a new C-band (5340-MHz) multi-parameter Doppler radar system with a bistatic Doppler radar network. The purpose is to establish the next-generation technology of precipitation observation for meteorological and hydrological applications, such as weather forecasting and run-off analysis for predicting floods. This new radar is named COBRA (CRL Okinawa Bistatic polarimetric RAdar). The weather targets of the system are typhoons, Baiu-frontal rainfall, meso-scale precipitation in subtropical zones, and clear-air turbulence. Two transmitter (klystron) units are used for to observe the polarization characteristics of precipitation particles. The transmission polarization for each pulse is selected from six possible polarizations. The return signal is measured simultaneously by two receivers, one for the horizontal polarization and the other for the vertical polarization.