An operational building-scale urban forecasting system: Pentagon Shield

Because the Pentagon is one of the most likely targets for a terrorist attack with chemical, biological, or radiological (CBR) weapons, a building CBR-protection system, called Pentagon Shield, has been developed to protect the Pentagon's 25,000+ occupants. Based on information provided by coupled meteorological and transport and diffusion (T&D) models and networked sensors, building ventilation systems can be adjusted in real time to minimize contamination, and potential evacuation routes can be identified. Such atmospheric modeling systems must represent multiple scales of motion, from the mesoscale to the building scale. In addition to meteorological data that represent this range of scales, in situ and remotely sensed information on CBR contaminants must also be ingested. Not only is this effort scientifically challenging, the computational requirements are so formidable that, to our knowledge, such physics-based atmospheric models that explicitly resolve detailed building effects have previously not been run operationally. Because the system consists of a nest of four different atmospheric models, some of which assimilate Doppler radar data and Doppler lidar data, it is one of the most complex operational modeling systems ever deployed for an urban area. This paper summarizes how the Pentagon Shield system produces operational analyses and forecasts for the mesoscale, the city scale, the neighborhood scale, and the building scale. What is being learned about urban meteorology, and about the technology employed, will allow for future applications of such systems for CBR protection in other cities as well as for urban field-program support.