Research Tower Could Aid Tracking Of Contaminant Plumes

Using data from the new network, which so far has 11 stations in the District, scientists expect to create and test computer models that would calculate neighborhood-scale projections of a plume's spread.

The analysis might also specify locations of contamination “hot spots,” says atmospheric physicist Christoph A. Vogel of the Air Resources Laboratory of the National Oceanic and Atmospheric Administration (NOAA) in Silver Spring, Md. That would enable first responders and citizens to know “which streets you would want to go down and which to avoid,” he adds.

The NOAA-funded network, known as UrbaNet, also supports activities of the Department of Homeland Security.

On Wednesday, June 20, Vogel and engineer Randy White mounted their instruments on the roof of the headquarters of the American Geophysical Union (AGU), 2000 Florida Ave., N.W., near the intersection of Florida and Connecticut Avenues N.W., not far from Dupont Circle.

AGU is an international organization of scientists who study and publish research on Earth and space sciences.

The new monitoring station will include a device called a sonic anemometer that uses high-frequency sound waves to measure wind velocity in all directions simultaneously at brief time intervals. With such data, scientists can analyze local air turbulence that strongly influences where and at what rate airborne contaminants spread in an urban environment, Vogel explains.

Although weather and climate researchers already employ well-developed models to forecast air movements on regional scales, “trying to work in a city, neighborhood by neighborhood, is still in its infancy,” Vogel notes. “Existing, large-area models scale with considerable difficulty to the size of neighborhoods,” he says, “At the same time, atmospheric-turbulence models for small domains can't easily address the bigger scale and complexities of urban terrain.”

Aside from the capital's suitability for the monitoring network for security reasons, the city is also an exceptional proving ground on another count: Its fairly uniform skyline—the result of building-height restrictions—results in air motion that is easier to model than it would be in cities, such as New York City, with more extreme height variations, Vogel says. However, the research team has also erected a handful of stations in New York City and elsewhere to pursue testing in other environments.

The roof that will receive the new instrument tower hosts another weather-monitoring station operated by a commercial weather service, called WeatherBug. By locating the new NOAA installation alongside the commercial instruments, the research team intends to evaluate the feasibility of tapping private meteorological networks to contribute to its urban atmospheric measurements.