MOUNTAIN VIEW, Calif., SGI today announced that an advanced numerical weather model from Science Applications International Corporation (SAIC) running on SGI(R) high- performance computing systems has been demonstrated as a powerful operational tool for real-time aerosol- and gas-hazard prediction. SAIC's Operational Multiscale Environment model with Grid Adaptivity (OMEGA(TM)) is a meteorological forecasting system that uses real-time weather data to model how the release of nuclear, biological and chemical (NBC) material by accident or terrorist attack might evolve based on atmospheric dynamics. The OMEGA modeling system, which is capable of rapid configuration for operation anywhere in the world, predicts the dispersion of hazardous material using real-time weather-data feeds from the National Oceanic and Atmospheric Administration, National Centers for Environmental Prediction, and U.S. Navy Fleet Numerical Meteorology and Oceanography Center. OMEGA has been used operationally for seven years to support forensic analyses, field experiments and mission support. A recent operational application of OMEGA included the monitoring of the Winter Olympics in Salt Lake City for potential terrorist attacks. "In this post-September 11 environment, there is a clear need to study and react to potential nuclear, biological and chemical terrorist threats," said John Burwell, senior director of government industry, SGI. "Dispersions of nuclear, biological and chemical agents in the air or within buildings can be studied and better understood in an effort to forecast outcomes and contingencies. SGI computers, from workstations on up to large SGI Origin family systems, are used throughout the world for weather forecasting and air- pollutant transport predictions on a short- and long-term basis, both locally and globally." Multiprocessor SGI high-performance computing systems running OMEGA are well suited to handle the large data sets and models required for this kind of hazardous aerosol- and gas-dispersion prediction. The atmosphere is a dynamic system that is constantly in motion, and atmospheric dispersion is a complex interdisciplinary problem covering a wide spectrum of fields including physics, meteorology, chemistry and mathematics. OMEGA is a robust prediction system capable of modeling dispersions on global, regional and urban scales. "Urban centers represent the densest population centers and are potentially the most vulnerable to accidents or terrorist attacks," said David Bacon, director, SAIC Center for Atmospheric Physics. "In recent years, urban centers have been exposed to nuclear, biological and chemical disasters. These events have crystallized the damage that can occur from the use of NBC material in an urban setting and provide the justification for considerable research to understand this complex phenomenon." An instantaneous or short-term, limited area release of an extremely hazardous material in or near an urban setting represents a highly complex computational problem. Predicting the dispersion of hazardous aerosols and gases in an urban environment requires much higher-resolution and higher- fidelity models than a regional forecast does. OMEGA has automatic linkage to worldwide data sets for surface elevation, land/water, vegetation coverage, soil type, land use, deep-soil temperature, deep-soil moisture and sea-surface temperature at varying resolutions. The modeling system is capable of simulating or forecasting atmospheric conditions at resolutions ranging from 100 km down to 1 km. A unique feature of the OMEGA model is its unstructured, dynamically adaptive grid, which facilitates the gridding of arbitrary surfaces and volumes in three dimensions. In particular, unstructured grid cells in the horizontal dimension can increase local resolution to better capture topography or the important physical features of atmospheric circulation flows and cloud dynamics. OMEGA represents the first attempt to use this computational fluid dynamics technique for atmospheric simulation.