Regional Specialized Meteorological Center for environmental emergency responses Washington

Regional Specialized Meteorological Centers for environmental emergency response (RSMC-EER) respond to environmental emergencies involving  fallout from large-scale nuclear accidents and other hazardous airborne releases. They provide forecasts showing the transport and dispersion of airborne materials so a global response can be coordinated.

RSMC Washington is a joint venture between the NOAA Air Resources Laboratory and the NOAA National Weather Service National Centers for Environmental Prediction (NCEP); merging the pollutant dispersion modeling and analysis capabilities of ARL with the forecast skills and operational capabilities at NCEP. In essence, NCEP provides the 24 hour per day initial contact point for assistance requests. In the event of an accident, NCEP runs the initial response model on their powerful supercomputer and distributes the products through a password-protected website. Model outputs are distributed to predesignated country representatives.

By agreement with the Canadian Meteorological Center (CMC), RSMCs Washington and Montreal respond jointly to emergencies in their region of concern, each sending products to countries requesting assistance, as well as consulting with each other regarding model output differences, product interpretation, and uncertainty. Regular IAEA quarterly and additional RSMC monthly exercises are conducted with the other RSMCs.

The standard model products to be distributed include forecasts of trajectories, exposures, and deposition using the HYSPLIT transport and dispersion model. There is a continuing program intended to identify occasions in which differences in RSMC predictions arise, and to find the causes for these differences. Dispersion model differences are partly due to differences in meteorological model’s spatial resolution as well as the effects of the Lagrangian or Eulerian methods used to compute the pollutant dispersion. Prediction differences will have to be addressed by emergency planners when confronted by multiple model output products. Regional RSMCs (such as Washington and Montreal) will issue joint statements on differences between their products.

RSMC trajectory during an exercise on June 24, 2025. Credit: NOAA ARL
Expert Team on Emergency Response Activities Meeting Oct 16-20, 2023 in Vienna, Austria. Credit: WMO

Background

As a result of the poor communications between countries following the Chernobyl accident in the Spring of 1986, the International Atomic Energy Agency (IAEA) and other international organizations asked the World Meteorological Organization (WMO) to create an  early warning system for messages about nuclear accidents to be transmitted over the Global Telecommunications System (GTS). This would also benefit WMO member countries that lacked extensive forecasting capability to have access to specialized pollutant transport and dispersion forecasts during these emergencies.

Initial Organization

In 1989, Regional Specialized Meteorological Centers at Toulouse (Meteo-France), Bracknell and Montreal were set up under interim arrangements between the WMO and the IAEA. Under these arrangements Meteo-France was to provide global coverage, with the UK Meteorological Office as the backup center, until each WMO region had at least two RSMCs for transport model products.

The need for transport and dispersion forecasts became even more apparent during the oil fire emergency after the Gulf War, when many organizations provided ground personnel with predictions of the smoke plume behavior. These predictions were often misleading; there was no existing and well-recognized system to sort out predictions from less experienced sources.

In November 1992, a demonstration of NOAA’s RSMC capabilities was made to the WMO Commission for Basic Systems (CBS). Following this demonstration, the NOAA RSMC was accepted by WMO and subsequently became effective 1 July 1993. The addition of RSMC Washington resulted in two RSMCs per WMO region (RA) – Washington and Montreal (RA IV) and Toulouse and Bracknell (RA VI) – and indicated the need to revise the interim arrangements. Under the new global arrangements, Region IV was responsible for parts of Central and South America Region III, while Toulouse and Bracknell (changed to Exeter in December 2003), would cover the remaining Regions I and II (Africa and Asia). These new global arrangements were finalized at the WMO/CBS session in August 1994.

Growth of RSMC’s 

Since 1992, other RSMCs have been accepted by WMO including Melbourne, Australia (RA V); Beijing, China (RA II); Obninsk, Russian Federation (RA II); Tokyo, Japan (RA II); Offenbach (RA VI); and Vienna (RA VI). RSMCs Melbourne and Beijing were initiated using some of ARL’s procedures and dispersion models. The RSMCs in Washington and Montreal provide backup to Melbourne until another RSMC is specified for RA V. RSMC Toulouse and Exeter are now responsible for RA I and VI.

Time of Arrival plot captured in Google Earth during an exercise on June 24, 2025. Credit: NOAA ARL

Future Work

A  transfer coefficient matrix (TCM) approach has been approved for implementation into the National Center for Environmental Protections operations. Developed after the Fukushima-Daiichi Nuclear Power Station radiological release in March 2011, the TCM is a mature capability now ready for operational deployment.  It computes source-receptor relationships based on time-resolved, unit source emissions simulations, allowing the TCM to be multiplied by actual emissions to determine downwind impacts. This approach enables rapid updates when new emissions estimates become available, eliminating the need to rerun transport and dispersion simulations—an essential capability for ongoing events and for incorporating improved emissions estimates. The TCM can  also be used to construct ensembles that represent uncertainty in emissions and to estimate emissions using available observations through an inversion algorithm.

Related Resources

Example RSMC Products from RSMC Washington
WMO Emergency Response Information
Technical document no. 778

Related Publications

Draxler, R.R., G.D. Rolph, J.T. McQueen, J.L. Heffter and B.J.B. Stunder, 1993: NOAA Washington GDPS Regional Specialized Meteorological Center on the Provision of Transport Model Products for Environmental Emergency Response.