Evaluation of Large Eddy Numerical Simulations (LES) with Observations from FUsing Sensor Information from Observing Networks (FUSION) Field Trial 2007 (FFT-07)

The FFT-07 field experiment was conducted at Dugway Proving Ground (DPG) in September 2007 with the intent of providing a high spatial and temporal resolution chemical tracer and meteorological data set that could be used to improve the accuracy of Department of Defense (DoD) transport and dispersion (T&D) modeling capabilities. Comprehensive propylene gas tracer dispersion and meteorological conditions were collected using 120 fast-response chemical sensors deployed at a 50 m horizontal spatial resolution covering an area of ~500x500m. The experiment also involved the collection of detailed boundary layer meteorological observations both at the surface and aloft.

In this study we evaluate the EULAG-LES and imbedded passive tracer T&D model using both the chemical and meteorological observations from the FFT-07 dataset. We assimilate time-varying surface and tower measurements, as well as sodar and radiosonde data to generate physically realistic atmospheric and tracer gas release conditions representative of the particular field trial. Simulations were created for trials with both instantaneousness and continuous tracer releases. Wind speed and direction, surface temperature as well as the instantaneous concentrations generated by the model are compared with field data at appropriate locations of the sensor network. Ensembles of model generated tracer gas releases were produced for each trial and used in the statistical analysis to characterize the model's ability to represent the tracer gas T&D properties. The results will be used to assess the suitability of this approach in simulating realistic chemical and biological (CB) agent releases for use in testing and evaluating CB defense systems.