CLOUD OBSERVATIONS WITH A POLARIMETRIC 33 GHZ AND 95 GHZ RADAR

The University of Massachusetts' Microwave Remote Sensing Laboratory ( MIRSL) has developed a unique high spatial resolution multiparameter r adar under sponsorship from the Department of Energy's Atmospheric Rad iation Measurement (ARM) program. The Cloud Profiling Radar System (CP RS) uses a single one-meter diameter dielectric lens antenna to make c ollocated polarimetric and Doppler measurements at both 33 GHz and 95 GHz. The polarization of each transmitted pulse at either frequency ca n be selected on a pulse-to-pulse basis. The radar and supporting hard ware are mounted on a truck that serves as a mobile laboratory. The tr uck-based platform permits CPRS to operate in remote locations and als o serves as an economical means of transporting the system. This paper describes the CPRS hardware and presents preliminary vertically point ing observations of mixed-phase stratus clouds obtained in the summer of 1993 during the first field test of the system. Measurements show M ie scattering in the ice region, melting layer and rain region of the clouds observed. To illustrate CPRS potential for particle sizing, mod els of differential reflectivity and differential mean Doppler velocit y are used to estimate median volume diameter, D-0, from dual-waveleng th reflectivity and Doppler measurements of rain.