Solid rocket motor exhaust model for alumina particles in the stratosphere

Based on available and new data, a unified model is presented for the particle size distribution, particle density, and geometrical dispersion for the alumina particles in the exhaust of solid rocket motor plumes in the stratosphere. The particle size distribution is trimodal with Sauter mean diameters of 0.056, 1.0, and 3.6 mu m. Nearly all of the particles lie within the small-size mode but nearly all of the mass lies in the large-size mode. Approximately two-thirds of the particle surface area available for heterogeneous chemical reactions is due to the large particle mode while most of the remaining surface area is due to the small particle made. The early horizontal dispersion rate of the plume is found to be about an order of magnitude greater than the dispersion rates used in several recent models of stratospheric ozone-plume chemistry.