The National Atmospheric Release Advisory Center (NARAC) is located at the University of California's

Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a Federally funded research and development centers, federally funded research and development center in Livermore, California, United States. Originally established in 1952, the laboratory now i ...

. 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 provides atmospheric 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 facility includes

* Scientific and technical staff who provide support and training for NARAC tools, as well as quality assurance and detailed analysis of atmospheric releases. * 24 hour x 7 day on-duty or on-call staff. * Training facility. * An Operations Center with uninterruptible power, backup power generators, and robust computer systems. * Links to over 100 emergency operations centers on the U.S. * A team of research and operational staff with expertise in atmospheric research, operational meteorology, numerical modeling, computer science, software engineering, geographical information systems, computer graphics, hazardous material (radiological, chemical, biological) properties and effects.

The Emergency Response System: Real time dispersion modeling

The NARAC emergency response central modeling system consists of an integrated suite of

meteorological Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agriculture ...

and atmospheric dispersion models. The meteorological

data assimilation Data assimilation refers to a large group of methods that update information from numerical computer models with information from observations. Data assimilation is used to update model states, model trajectories over time, model parameters, and ...

model, ADAPT, constructs fields of such variables as the mean

wind Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

, and

turbulence In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...

. Non-divergent wind fields are produced by a procedure based on the variational principle and a finite-element discretization. The dispersion model, LODI, solves the 3-D advection-diffusion equation using a Lagrangian

stochastic Stochastic (; ) is the property of being well-described by a random probability distribution. ''Stochasticity'' and ''randomness'' are technically distinct concepts: the former refers to a modeling approach, while the latter describes phenomena; i ...

Monte Carlo method Monte Carlo methods, or Monte Carlo experiments, are a broad class of computational algorithms that rely on repeated random sampling to obtain numerical results. The underlying concept is to use randomness to solve problems that might be ...

. 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 In the physics of aerosols, deposition is the process by which aerosol particles collect or deposit themselves on solid surfaces, decreasing the concentration of the particles in the air. It can be divided into two sub-processes: ''dry'' and ''w ...

, and buoyant/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.Hodur, R. M. (1997), ''The Naval Research Laboratory's Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS)'', Mon. Wea. Rev., 125, 1414-1430.

References

External links and sources

National Atmospheric Release Advisory Center
(official website)
Lawrence Livermore National Laboratory
(official website) {{Lawrence Livermore National Laboratory, state=autocollapse Atmospheric dispersion modeling Lawrence Livermore National Laboratory

The NARAC facility includes

The Emergency Response System: Real time dispersion modeling

See also

References

External links and sources