This award is part of a collaborative project among Professor McIntosh of the University of Massachusetts (Amherst), Professor Vali of the University of Wyoming (Laramie), and Professor Gogineni of the University of Kansas (Lawrence). The objective is to study fine-scale structure of clouds using millimeter-wave radars. Historically, cloud structures and dynamics have been probed at two widely separate resolutions. On the one hand, airborne microphysical probes, such as the widely used laser optical probes, have volume resolution of the order of 1.E-4 to 1.E-2 m3 for 1-second samples. On the other hand, ground-based research radars at wavelengths greater than 1 cm typically have volume resolution of the order of 1.E4 to 1.E7 m3. However, some important processes in cloud evolution lie between these two resolution categories; these include ice formation, entrainment, in-cloud mixing, and initiation of coalescence. The development of depolyment of millimeter-wave radars supported by this award will allow scientists to better understand these fine-scale processes with appropriate tools. During the first half of this project, the Principal Investigators will conduct ground-based experiments at the UWyoming Elk Mountain Observatory and examine the radar backscatter data from ice crystals of known shape, size and habitats at 35, 95 and 215 GHz. During the second half of this project, the UMass fully polarimetric 95 GHz radar will be installed in the NCAR King Air research aircraft; collaborating with NCAR scientists, the Principal Investigators will investigate how such a facility can serve the greater meteorology community.