This study was the subject of a Ph.D. dissertation by one of the authors (Scott, 1999). The authors are deeply indebted to Steve McCrary (deceased) for his dedicated work on the New Mexico Tech dual-polarization radar. The work was supported in part by the U.S. Air Force Office of Scientific Research, under Grants AFOSR-89-0450, F49620-92-J-0320 (AASERT), and F49620-96-1-0304. It was also supported in part by the New Mexico Universities Collaborative Research Program (NUCOR) of the Los Alamos National Laboratory.