Interagency Modeling and Atmospheric Assessment Center

Interagency Modeling and Atmospheric Assessment Center
Name	Interagency Modeling and Atmospheric Assessment Center
Abbreviation	IMAAC
Formation	2003
Headquarters	Washington, D.C.
Region served	United States and international partners
Parent organization	Department of Homeland Security

Interagency Modeling and Atmospheric Assessment Center

The Interagency Modeling and Atmospheric Assessment Center provides operational atmospheric plume modeling and consequence assessment for chemical, biological, radiological, nuclear, and hazardous incidents. It supports Department of Homeland Security, Federal Emergency Management Agency, Environmental Protection Agency, Department of Defense, and international partners including World Health Organization and North Atlantic Treaty Organization in incident planning and response. The center integrates tools used by National Oceanic and Atmospheric Administration, National Aeronautics and Space Administration, Centers for Disease Control and Prevention, U.S. Geological Survey, and academic laboratories such as Massachusetts Institute of Technology and California Institute of Technology.

History

IMAAC was established in the wake of heightened concern about mass-casualty incidents following events like the September 11 attacks, the 2001 anthrax attacks, and lessons from Hurricane Katrina. Early collaboration involved agencies with operational modeling expertise including NOAA's Air Resources Laboratory, EPA's National Homeland Security Research Center, and the Defense Threat Reduction Agency. Over time the center incorporated advances from programs such as National Science Foundation-funded atmospheric research, partnerships with Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, and modeling techniques developed for Chernobyl disaster and Fukushima Daiichi nuclear disaster consequence assessment.

Mission and Functions

IMAAC’s mission centers on providing timely plume predictions, exposure estimates, and consequence analyses to support decision-makers in situations comparable to Tokyo subway sarin attack scale releases or larger. It delivers model output for tactical decisions used by FBI, U.S. Northern Command, and state-level emergency management offices including California Office of Emergency Services and New York City Office of Emergency Management. Functional outputs include hazard maps, protective action recommendations akin to guidance from World Health Organization and Centers for Disease Control and Prevention, and integration with situational awareness platforms such as those used by United Nations Office for Disaster Risk Reduction.

Organizational Structure and Participating Agencies

IMAAC operates as a multi-agency hub with governance and technical steering committees drawing representatives from Department of Homeland Security, NOAA, EPA, CDC, DTRA, U.S. Army Corps of Engineers, and national laboratories including Sandia National Laboratories and Argonne National Laboratory. Regional liaisons coordinate with state and local partners including Texas Division of Emergency Management and Florida Division of Emergency Management. International collaboration is maintained with entities like European Union civil protection mechanisms and NATO Allied Command Transformation for interoperability exercises.

Modeling Systems and Tools

IMAAC employs an ensemble of atmospheric dispersion and consequence assessment systems such as HYSPLIT, FLEXPART, RASCAL, and proprietary implementations of Gaussian plume and Lagrangian particle models. It integrates meteorological input from Global Forecast System, European Centre for Medium-Range Weather Forecasts, and observational data streams from Doppler radar, GOES satellites, and surface networks tied to National Weather Service. Visualization and decision-support leverage platforms developed by Esri, high-performance computing at National Center for Supercomputing Applications, and data assimilation methods used in Ensemble Kalman filter studies.

Operations and Emergency Response

During incidents IMAAC coordinates rapid modeling briefings with operational centers including National Response Coordination Center and regional FEMA Regional Offices. Scenarios range from accidental industrial releases similar to Bhopal disaster-scale events to deliberate attacks studied in Project BioShield-style preparedness. The center's products feed into shelter-in-place and evacuation planning used by municipal authorities such as Los Angeles Fire Department and Chicago Office of Emergency Management and Communications, and inform protective action recommendations echoing protocols from World Health Organization and Centers for Disease Control and Prevention.

Research, Development, and Validation

IMAAC maintains active research efforts with universities and laboratories to validate models against historical incidents and field experiments such as tracer releases comparable to studies by Argonne National Laboratory and Lawrence Berkeley National Laboratory. Validation draws on case studies including Chernobyl disaster plume reconstructions and dispersion analyses from Fukushima Daiichi nuclear disaster. Collaborative projects have included method development funded by National Science Foundation and algorithmic work with NASA for satellite-derived source estimation techniques.

Notable Deployments and Impact

IMAAC provided modeling support during national-scale events and exercises, advising on plume trajectories for scenarios associated with high-profile incidents and preparedness drills conducted with FEMA National Exercise Program and Operation Flintlock-style exercises. Its assessments have been cited in interagency after-action reports alongside contributions from NOAA, EPA, and CDC, and influenced policy discussions in forums such as Homeland Security Advisory Council and congressional hearings in the United States House of Representatives.

Category:United States federal agencies Category:Disaster preparedness Category:Atmospheric dispersion modeling