Evaluation of a randomized rainfall enhancement program over West Texas in 1987



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Texas Tech University


The SouthWest Cooperative Program (SWCP) is a rainfall enhancement program initiated in 1983 to develop a scientifically sound and socially acceptable technology for the enhancement of summertime rainfall over the Texas-Oklahoma region. The goal of this thesis is the analysis of the fifteen randomized cases obtained during the 1987 SWCP summer field project. The main objectives in this analysis are an examination of how the selection and treatment criteria were applied to each case and an evaluation of whether or not the criteria should be changed.

Examination of the selection criteria showed that four of the fifteen cases that were qualified as experimental units failed to meet all of the criteria. However, for the most part these cases were not typical of the SWCP experimental design. Overall, the selection criteria appear to be appropriate for the field conditions and no changes should be made in future field projects.

A composite analysis was performed on corrected samples of seeded and control cases and showed differences between the two groups. The seeded cases remained stronger during their lifetime, continuously increased their vertical extent and persisted longer than the control cases. The differences noted in the composites show that when all criteria were met the seeded and control cases behaved quite differently.