Atmospheric Wind and Diffusion from Analysis of an SF6 Release at 350 km Altitude.

Analysis of intensified video imagery of the nighttime release of sulfur hefafluoride at 350 km altitude has provided the first measurements of atmospheric diffusion and wind velocity at high altitude. The measurements apply to validating models of atmospheric dynamics and of the reactions and transport of the released species. Images taken through a wide angle lens system with OI 7774 and 6300 A narrow band pass filters at its telecentric stop were digitized to determine the image plane locations of stars and spatial distribution of the release-induced glow. Photogrammetric procedures were applied to determine orientation of the airborne camera from the image positions of the known bright stars. Single-site triangulation was performed to locate the glow center in a time sequence of images, from which the atmospheric wind components were determined. The distribution of glow irradiance recorded in the images were analyzed to determine time dependent spatial halfwidths of the cloud, from which its diffusive growth was determined.