Seed___ PO S T Wall Clouds Distance from Hurricane Center Ow FIGIJRE 12.-Radial profiles of temperature, pressure, and windspeed for a mature hurricane before (solid curves) and possible changes after (dashed curves) seeding. (The solid curves are the same as those in fig. 11.) (From Gentry. 19T4.) Hurricane seeding experiments were undertaken by the Department of Commferce and other agencies of the Federal Government in 1961, initiating what came to be called Project Stormfury. To date only four hurricanes have~ actually been seeded under this project-all of them between 1961 and 1971; however, Stormfury has also included investigation of fundamental properties of hurricanes and their possible modification through computer modeling studies, through careful measurements of hurricane properties with research probes, and through improvements in seeding capabilities. The goal of hurricane seeding is the reduction of the maximum winds through dispersing the energy normally concentrated in the relatively small band around the center of the storm. The basic rationale for seeding a hurricane with silver iodide is to release latent heat through seeding the clouds in the eye wall, thus attempting to change the temperature distribution and consequently weaken the sea level pressure g-,radient. It is assumed that the weakened pressure. gradient will allow outward expansion, with the result that the belt of maximum winds will migrate away from the center of the storm and will therefore weaken. Actually, stimulation of condensation releases much more latent heat than first hypothesized in 1961, and theoretical hurricane models show that a new eye wall of gre ater'dia meter can be developed by encouraging growth of cumulus clouds through dynamic seeding.49 49 Ibid., pp. 510-511.