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I I I I I I. I I I I I I I I I I I I I During the season there were 16 Operational Seeding Periods and 12 Experimental Periods. The University of Delaware was responsible for the management of a state-wide raingage n.etwork which collected data primarily during the Experimental Period. The University, under separate report, will conduct an analysis of the rainfall measurements. During the active seed periods, ejectable AgI pyroteclmic cartridges were utilized to seed selected cloud turrets. The aircraft normally delivered the AgI by penetrating the developing cloud turrets, near the _10GC level, and ejecting the flares vertically downward through the updraft core region. The small AgI crystals spread rapidly through the updraft creating new ice crystal sites which sub- sequently grow at the expense of the supercooled water droplets. This relatively rapid glaciation of the cloud updraft, releaHes latent heat, which then leads to increased buoyancy within the updraft region. The response to the increased buoyancy is manifested in a greater vertical growth of the cloud, increased condensation, and a prolonga- tion of the precipitation growth mechanisms and in turn a prolongation of the precipitation fallout patterns. Sequential seeding of new cloud turrets, along a given cloud complex, results in aeral expansion of the rain areas and rainfall of longer duration. This increase in rain area and duration is believed to be the main mechanism for wide-area rain augmentation. Certain data was collected during the operations and analyzed in an attempt to describe and identify the principle meteorological and physical changes occurring during these experiments. In this report, only cursory analysis was made of the radar ec ho time histories for the Operational Period. Attention was given only to execution, seeding strategy, and general echo response. The primary data analysis was 121 _.