PROJECT SAND STORM, AN EXPERIMENTAL PROGRAM IN ATMOSPHERIC DIFFUSION

: A series of field experiments in atmospheric diffusion was conducted at Edwards Air Force Base, California, in 1963. The primary feature which distinguished this series from similar experimental investigations was that instantaneous sources were studied. Puffs of tracer material were generated quasi-instantaneously by short bursts of small, horizontally fired, solid propellant rocket motors. Tracer samples were collected on a horizontal grid that had 350 sampling positions. All of the 43 experiments were conducted under thermally unstable atmospheric conditions. Analyses of the data identified the region of the turbulent energy spectrum which contains the eddies that are effective in diffusing the clouds. Eulerian measurements of turbulence are shown to be correlated with lateral rates of cloud growth. Downwind distributions of peak inhalation-level dosages were found to be quite irregular, with the anomalies unpredictable on the basis of measurable meteorological parameters. It was, nevertheless, possible to develop an operationally useful estimating equation relating peak dosages to distance from the source.