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Urban Dispersion Program: Urban Measurements Applied to Emergency Response

Description: Air motions in and around cities are highly complex, and the increasing threat of harmful releases into urban atmospheres makes advancing the state-of-science of understanding and modeling atmospheric flows and dispersion in and around cities essential. The four-year Urban Dispersion Program (UDP) funded primarily by the U.S. Department of Homeland Security and the Defense Threat Reduction Agency has recently been completed. The program’s primary focus was to conduct tracer and meteorological field studies in Manhattan to improve our understanding of flow and dispersion of airborne contaminants through and around the deep street canyons of New York City, including outdoor-indoor-subway exchange mechanisms. Additionally, urban dispersion models are being validated and first-responder guidance are being refined using data collected during the two UDP field studies. Pacific Northwest National Laboratory led several government laboratories, universities and private companies in conducting the two UDP field studies. The first study was a small-scale study that investigated dispersion in the immediate vicinity of the Madison Square Garden during March 2005 (MSG05), while the second UDP study was an extensive study conducted during August 2005 in Midtown Manhattan (MID05). A brief overview of the UDP field studies will be given followed by a discussion of some limitations of current urban models in simulating dispersion in urban areas. Some first-responder guidance based on findings from recent urban field studies will also be presented.
Date: September 10, 2007
Creator: Allwine, K. Jerry; Clawson, Kirk L.; Flaherty, Julia E.; Heiser, John H.; Hosker, Rayford P.; Leach, Martin J. et al.
Partner: UNT Libraries Government Documents Department

Evaluation study of building-resolved urban dispersion models

Description: For effective emergency response and recovery planning, it is critically important that building-resolved urban dispersion models be evaluated using field data. Several full-physics computational fluid dynamics (CFD) models and semi-empirical building-resolved (SEB) models are being advanced and applied to simulating flow and dispersion in urban areas. To obtain an estimate of the current state-of-readiness of these classes of models, the Department of Homeland Security (DHS) funded a study to compare five CFD models and one SEB model with tracer data from the extensive Midtown Manhattan field study (MID05) conducted during August 2005 as part of the DHS Urban Dispersion Program (UDP; Allwine and Flaherty 2007). Six days of tracer and meteorological experiments were conducted over an approximately 2-km-by-2-km area in Midtown Manhattan just south of Central Park in New York City. A subset of these data was used for model evaluations. The study was conducted such that an evaluation team, independent of the six modeling teams, provided all the input data (e.g., building data, meteorological data and tracer release rates) and run conditions for each of four experimental periods simulated. Tracer concentration data for two of the four experimental periods were provided to the modeling teams for their own evaluation of their respective models to ensure proper setup and operation. Tracer data were not provided for the second two experimental periods to provide for an independent evaluation of the models. The tracer concentrations resulting from the model simulations were provided to the evaluation team in a standard format for consistency in inter-comparing model results. An overview of the model evaluation approach will be given followed by a discussion on the qualitative comparison of the respective models with the field data. Future model developments efforts needed to address modeling gaps identified from this study will also be discussed.
Date: September 10, 2007
Creator: Flaherty, Julia E.; Allwine, K Jerry; Brown, Mike J.; Coirier, WIlliam J.; Ericson, Shawn C.; Hansen, Olav R. et al.
Partner: UNT Libraries Government Documents Department

Bronx Zoo Fuel Cell Project

Description: A 200 kW Fuel Cell has been installed in the Lion House, Bronx Zoo, NY. The Fuel Cell is a 200 kW phosphoric acid type manufactured by United Technologies Corporation (UTC) and will provide thermal energy at 725,000 Btu/hr.
Date: September 30, 2007
Creator: Pham, Hoang
Partner: UNT Libraries Government Documents Department