A Comparison in the Accuracy of Mapping Nuclear Fallout Patterns Using HPAC, HYSPLIT, DELFIC FPT and an AFIT FORTRAN95 Fallout Deposition Code

Four nuclear fallout mapping tools are studied to determine which tool predicts the most accurate fallout dose-rate contours with low computation time and resources. The four programs consist of the FORTRAN95 based Fallout Deposition Code (FDC), the Hazard Prediction and Assessment Capability’s (HPAC) Nuclear Weapon (NWPN), the Defense Land Fallout Interpretative Code (DELFIC) Fallout Planning Tool (FPT) and the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) Model. The models were compared to the Defense Nuclear Agency’s (DNA) DNA 1251-1-EX, Compilation of Local Fallout Data from Test Detonations 1945-1962 Extracted from DASA 1251, using Warner and Platt’s Measure of Effectiveness (MOE) method. In order to accurately compare models the use of the FDC and low resolution weather data was validated. HYSPLIT trials were studied varying the vertical distribution, horizontal distribution, emission rate, emission time and number of equal activity particle groups. HPAC trials were run varying the use of terrain and the terrain resolution and the DELFIC FPT trials were ran varying the length of time the ground zero winds were incorporated. The best results of each of the four nuclear mapping tools were compared with the results culminating in the determination that the DELFIC FPT is the preferred nuclear mapping tool.