Location and Date:

Washington D.C., in April/May 2004.

Overview:

The Field Research Division took part in a tracer experiment called Pentagon Shield in April/May 2004. Government officials requested a study at the Pentagon due to its high target value for terrorists. The Defense Advanced Research Protection Agency (DARPA) and the Pentagon Force Protection Agency (PFPA) sponsored this study. Scientists from several other Federal and National agencies were also involved in the study.

Objectives:

• To advance the physical processes governing dispersion around the Pentagon;

• Use results to improve, refine and verify a computer model that simulates the atmospheric transport of potential contaminants around the Pentagon.

Summary:

FRD released the tracer sulfur hexafluoride (SF₆) and collected the data during six Intensive Observation Periods (IOPs). SF₆ concentrations were sampled and measured as the tracer dispersed in and around the Pentagon. Sampling was done using 100 programmable integrating gas samplers (PIGS). Extra samplers were also deployed at selected stations for quality control. Quasi-instantaneous measurements were taken using 8 fast-response tracer gas analyzers (TGAs) including one van-mounted TGA that was driven to varying locations to intercept the dispersing tracer plumes. FRD also deployed a sonic anemometer and temperature/relative humidity probe to help measure turbulence and stability at the release site.

Images:

Release and miscellaneous pictures

Publications:

• Warner, T., P. Benda, S. Swerdlin, J. Knievel, E. Argenta, B. Aronian, B. Balsley, J. Bowers, R. Carter, P. A. Clark, K. L. Clawson, J. Copeland, A. Crook, R. Frehlich, M. L. Jensen, Y. Liu, S. Mayor, Y. Meillier, B. Morley, R. Sharman, S. Spuler, D. Storwold, J. Sun, J. Weil, M. Xu, A. Yates, Y. Zhang, 2006: The Pentagon Shield Field Program: Toward critical Infrastructure Protection. Bull. Am. Met. Soc.

Collaborators:

• NOAA ARL Atmospheric Turbulence and Diffusion Division (ATDD)

• Defense Advanced Research Projects Agency

• National Center for Atmospheric Research

• Coherent Technologies, Inc. (CTI)

• University of Colorado

Contact:

Roger Carter
1750 Foote Dr.
Idaho Falls, ID 83402
(208)526-2745
email: Roger.Carter@noaa.gov