This research continues the development of new instrumentation relevant to the advancement of cloud seeding technology and the analysis of data collected to better understand cloud seeding potential in winter orographic clouds. Instrumentation development included the state of construction of a NOAA type dual frequency radiometer for the continuous measurement of supercooled liquid water and the completion of an expendable balloon-borne system for measuring vertical profiles of supercooled liquid water. The analysis of data collected on the project was directed primarily at the interpretation of the vertical profiles of supercooled liquid water and vertical motion. Results indicate that sharp vertical gradients of supercooled liquid water often exist in winter orographic clouds. The relationships between measured supercooled liquid water and other variables strongly support previous findings that the precipitation augmentation potential of winter orographic clouds is substantial when the cloud top temperature is -22°C or warmer ad the cross-barrier wind speed (at mountaintop levels) is 8 m s -1 or greater.
Hill, Geoffrey E., "Research on Increased Winter Orographic Precipitation by Cloud Seeding (FY 1980)" (1980). Reports. Paper 421.