TheNational Atmospheric Release Advisory Center (NARAC) is located at the University of California'sLawrence Livermore National Laboratory. It is a national support and resource center for planning, real-time assessment, emergency response, and detailed studies of incidents involving a wide variety of hazards, including nuclear, radiological, chemical, biological, and natural emissions.
NARAC provides tools and services to federal, state and local governments, that map the probable spread of hazardous material accidentally or intentionally released into the atmosphere.
NARAC providesatmospheric plume predictions in time for an emergency manager to decide if protective action is necessary to protect the health and safety of people in affected areas.
The NARAC emergency response central modeling system consists of an integrated suite ofmeteorological andatmospheric dispersion models.[1][2] The meteorologicaldata assimilation model, ADAPT, constructs fields of such variables as the meanwinds,pressure,precipitation,temperature, andturbulence.[3] Non-divergent wind fields are produced by a procedure based on the variational principle and afinite-element discretization. The dispersion model, LODI, solves the 3-D advection-diffusion equation using aLagrangianstochastic,Monte Carlo method.[4] LODI includes methods for simulating the processes of mean wind advection, turbulent diffusion, radioactive decay and production, bio-agent degradation, first-order chemical reactions,wet deposition, gravitational settling,dry deposition, andbuoyant/momentum plume rise.
The models are coupled to NARAC databases providing topography, geographical data, chemical-biological-nuclear agent properties and health risk levels, real-time meteorological observational data, and global and mesoscale forecast model predictions. The NARAC modeling system also includes an in-house version of the Naval Research Laboratory's mesoscale weather forecast model COAMPS.[5]
