Wind features during the Jack Rabbit program tests in April-May 2010 at Dugway

The ten Jack Rabbit (JR) tests were conducted during light and variable wind conditions at a special site on the desert of Dugway Proving Grounds. This site in the northwest region of the sparsely vegetated playa soil at DPG had unique wind conditions impacting the initially dense gas clouds of chlorine or anhydrous ammonia as they dispersed into tracer clouds often made visible by the formation of ice crystals and fog. In the near-field region, chlorine gas was clearly visible, however, the anhydrous ammonia vapor was always invisible. The site was in the leeward region northeast of the northern end of the Granite Peak and south of a long arc of low dunes along the border to the salt flats. The usually weak winds for JR were influenced by these surrounding different land use categories and topography. The non-hydrostatic boundary layer calculations unique to the OMEGA mesoscale model (http://vortex.saic.com/) were applied to the JR weather reconstructions so that prevailing micrometeorological conditions could be estimated, as are needed to describe the cloud scale winds and turbulence impacting on the initially high inertia TIH source clouds. Evaluation of the OMEGA micrometeorological predictions against available field observations is pending.