Date of Award


Document Type


Degree Name

Master of Science


Department of Engineering Physics

First Advisor

H. Rose Tseng, PhD


Uncertainty associated with determining the source location of nuclear pollutants in the atmosphere after a nuclear fallout using a numerical model is difficult to determine. Uncertainty can originate from input data (meteorological and emissions), internal model error, physics parameterizations, and stochastic processes. This study uses the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model with data from the 1983 Cross Appalachian Tracer Experiment (CAPTEX) (Ferber et al. 1986) and simulating six nuclear detonations (Rolph et al. 2014) to quantify and communicate uncertainty in ensemble dispersion simulations. This is accomplished by utilizing an ensemble of forward trajectory simulations varying initial conditions and physical parameterizations (e.g. turbulence, boundary layer stability and mixed layer depth). The model rank for each simulation is calculated using ground measurements. This value is compared against the observed rank from the CAPTEX experiment to measure the sensitivity of each model run. Effectively quantifying and communicating uncertainty is crucial in providing probabilistic results in nuclear monitoring.

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