Comparative Investigation of Source Term Estimation Algorithms for Hazardous Material Atmospheric Transport and Dispersion Prediction Tools

Abstract : The release of hazardous materials into the atmosphere on the battlefield or in populated areas must be considered for future scenarios. Given a warning based on detections at a few sensors, it should be useful to rapidly provide an estimate of the location, time of release, and amount of material released. Such information could lead to refined predictions of the hazardous area and support follow-on actions to investigate the cause and nature of the hazardous release. In September 2007, a short-range test - Fusing Sensor Information from Observing Networks (FUSION) Field Trial 2007 (FFT 07) - designed to collect data to support development of prototype source term estimation (STE) algorithms was conducted. A comparative investigation of STE algorithms began in 2008. First, a subset of sensor data from selected FFT 07 trials was provided to participating algorithm developers. Next, developers provided blind STE predictions that were then independently compared to parameters of the actual release. Eight STE algorithm developers participated in this exercise. Fourteen full and partial sets of predictions were received with some exercise participants providing multiple sets of predictions based on different algorithms they have been developing. This evaluation considered several variables that might influence results including the number of sensors (4 vs. 16), the release type (instantaneous vs. continuous), the time of the release (day vs. night), meteorological inputs (research-grade inputs vs. simulated operational inputs), and the number of sources (single vs. double vs. triple vs. quad releases). The results of these analyses are used to ascertain trends among different sets of STE predictions and are presented in this paper.