Application of the Monte Carlo Particle Dispersion Model : to simulation of battlefield obscurants

The essential input for an optical study of short-term dispersion of battlefield obscurants is a particle number density and size distribution at a particular line of sight. Such distributions should account for source munition characteristics, prevailing atmospheric conditions, and temporal and spatial dependence. The MoCaPD model provides number and size densities satisfying these criteria.

The computational time of the MoCaPD, although comparable to alternate diffusion models, is excessive for real time simulations for application to visual displays. However, a method of rapidly simulating particle number densities using the particle counts from the MoCaPD model has been devised. An ensemble of particle counts is generated for a specific environment and obscurant source as a function of position and time using the MoCaPD computer program. A theoretical probability distribution is then fit to a statistical ensemble of several realizations determined from repeated runs of the MoCaPD program. From this distribution, a probabilistic simulation of MoCaPD number densities is constructed. The simulated densities are transformed into a time-varying, color-coded, spatial distribution of optical transmittance for a selected battlefield munition and prevailing meteorological conditions. Results of the simulation program have been validated against the MoCaPD model. The capabilities of the program include simulated views of transmittance as either a time sequence or as a number of individual statistical realizations of smoke patterns at a specified time. The model conveys visual information regarding transmittance through battlefield obscurants in a manner not otherwise obtainable and provides a rapid and effective tool with which to graphically analyze obscurant data.