A 35 GHz Mobile Doppler Radar and a Microwave Disdrometer Network for Meteorological Research

A mobile pulse Doppler Radar system with dual polarization receive capability is described. To increase system sensitivity, separate antennas are used for the transmitter and receiver. The transmitter power is more than 150 kW and the waveguide is pressurized at 40 psi of dry nitrogen. The Magnetron Transmitter pulse width is 250 ns with a duty cycle of 0.0005.The transmitter can be fully controlled via a RS-232 bus and the dual-polarization receiver operating at 132.5 MHz is fully digital making the radar remotely controllable. The receiver has an overall Noise Figure of about 4.5 dB and the STALO is a phase-locked/Multiplier type. The computer controlling the Radar is also the data acquisition computer and has the NCAR TITAN software loaded in the system. The Radar is now undergoing the final testing and tune-up and it is expected to be fully operational within the next couple of months. PLUDIX, an X-band microwave disdrometer, has obtained interesting results both as a stand alone instrument and in combination with meteorological radars. As a single measuring instrument placed in three locations at different elevations (including Tibetan plateau at 3300 m MSL) it has shown that collisional break-up position in the power spectrum increases towards higher frequencies with increasing altitude, while a mini-network of three under close coverage of a C-band radar (Project Aeroclouds) has shown the capability to fill the gap between the lowest useful elevation and the ground. This role is expected to be enhanced when the Ka mobile radar here described will be used in combination with a network of nine PLUDIX in a middle size basin. This combination will also be in perspective an optimal arrangement in a ground truth testing supersite for space-borne active sensors.