Advanced Modeling Tools
National Atmospheric Release Advisory Center (NARAC)
NARAC
provides a suite of multi-scale (local-, regional-, continental- and global-scale) atmospheric flow and dispersion models for a wide range of hazards. Some of the key features of this modeling system are:
- Automated, and validated real-time 3-D centralized modeling system at NARAC that simulates complex wind flows, detailed particle dispersion, wet and dry deposition on multiple spatial scales:
- Local-scale and regional-scale meteorological forecast and dispersion models
- Long-range meteorological forecast and dispersion models
- Models re-locatable anywhere in the world in real-time
- Nuclear explosion fallout model
- Fast-running, deployable local-scale dispersion model
The NARAC emergency response central modeling system consists of a coupled suite of meteorological and dispersion models. The data assimilation model, ADAPT, constructs fields of such variables as the mean winds, pressure, precipitation, temperature, and turbulence, using a variety of interpolation methods and atmospheric parameterizations. Non-divergent wind fields are produced by an adjustment 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, Monte Carlo method. 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, 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.
Each model used by NARAC must meet these requirements:
- Numerical methods must be verified using exact mathematical solutions
- Model results must be evaluated using field experiments
- New modeling methods developed must be documented and peer-reviewed
- Modeling system must be robust and efficient in operational applications
- Emergency response models must be able to produce results in near real-time
- Input data required by the models (for example, meteorological data and geographical data) must be available operationally.
CALMET/CALPUFF
This
is an advanced non-steady-state meteorological and air quality modeling system developed and distributed by Earth Tech and adopted by the EPA for a number of air quality impact assessment applications. The modeling system consists of three main components and a set of preprocessing and postprocessing programs.
The main components of the modeling system are:
- CALMET (a diagnostic 3-dimensional meteorological model)
- CALPUFF (an air quality dispersion model)
- CALPOST (a postprocessing package).
Each of these programs has a graphical user interface (GUI). In addition to these components, there are numerous other processors that may be used to prepare geophysical (land use and terrain) data in many standard formats, meteorological data (surface, upper air, precipitation, and buoy data), and interfaces to other numerical forecast models.
CALMET/CALPUFF are not designed as emergency response models but may be useful for emergency preparedness modeling in complex terrain environments.
For further information on the Modeling Toolbox, please contact Cliff Glantz or Carl Mazzola.
See also: Basic Modeling Tools