Overview of the Jack Rabbit II (JR II) Field Experiments and Summary of the Methods Used in the Dispersion Model Comparisons

This paper serves as an introduction to the special Atmospheric Environment issue on comparisons of 17 widely-used dense-gas dispersion models using observations from the Jack Rabbit II (JR II) chlorine release experiments, which were led by the U.S. Department of Homeland Security Science & Technology (DHS S&T) Chemical Security Analysis Center (CSAC) and a collaborative team of interagency partners, and conducted at the U.S. Army Dugway Proving Ground in 2015 and 2016. Nine of the 17 models that were compared were from outside the U.S. Other papers in the Special Issue describe specific aspects (e.g., observations of emissions, meteorology, and concentrations) of the JR II field experiments, results of individual dispersion model simulations for the models and comparisons of model predictions with JR II observations and other models. This paper provides a general overview of the field experiments and a brief summary of the model comparison goals and methods.