NARRAGANSETT, R.I. – July 29, 2008 – If a small orange parachute attached to a white Styrofoam box drifts gently into your yard from high above, don’t worry.
That’s the reassuring word from John Merrill, an atmospheric chemist at the University of Rhode Island, who releases a weather balloon from the URI Bay Campus in Narragansett every week as part of a research project to collect information about ozone concentrations in the atmosphere.
Over the span of two hours, the five-foot diameter balloon rises to 115,000 feet, where the temperature reaches -75 degrees Fahrenheit, and expands to a diameter of 29 feet, whereupon the balloon bursts and the instruments in the Styrofoam box float back to Earth with the support of the parachute.
“We’re making basic observations to document the state of the atmosphere to learn how it works,” said Merrill. “Ozone is an important greenhouse gas, so it’s important to document its distribution in the atmosphere and determine how it moves.”
Ozone is a form of oxygen that is produced naturally by ultraviolet light from the sun and is abundant in the upper atmosphere, where it shields the Earth from ultraviolet radiation. Low-level ozone is created when nitrogen oxides and hydrocarbons from power plant and vehicle emissions and other sources react with sunlight.
“It’s the same gas as is in the stratosphere, but when it’s found where we live it can be harmful,” Merrill said. “It’s toxic, so it irritates the eyes, skin, nasal passages and lungs, and it makes breathing problems worse. It even reduces the growth rate of plants.”
Air quality becomes a concern when ozone levels reach 80 parts per billion, and levels over 120 parts per billion are considered a serious health hazard, according to Merrill. Ozone alert days are declared in Rhode Island about a dozen times a year when levels surpass those allowed by federal regulations – 120 parts per billion for one hour or 75 parts per billion for eight hours.
URI is one of 30 sites around the world where weather balloons are released weekly to collect ozone data. Other U.S. sites include Boulder, Col., Huntsville, Ala., Trinidad Head, Cal., and Wallops Island, Va. The data is collected by the World Ozone Data Center in Toronto, Ontario, where it is freely available to scientists and the general public.
Thirty minutes prior to releasing the balloon each week, Merrill alerts the Federal Aviation Administration at T.F. Green Airport because the balloon can be detected by the air traffic control radar. As the balloon ascends, it reports data directly to URI in real-time via a radio transmitter.
Of the 275 balloons that Merrill has released since 2004, most are carried by prevailing winds to the east and land in the ocean, where many have been retrieved by whale watching boats and fishermen or washed ashore on beaches. About one in ten touches down on land, mostly in Rhode Island or southeastern Massachusetts, with the farthest reported last week from an island in Penobscott Bay, Maine.
The Styrofoam box containing the instrumentation is labeled with Merrill’s contact information and a notice that the package is not dangerous. A $30 reward is offered for its return.
Funding for the project comes from the National Aeronautics and Space Administration and the National Oceanic and Atmospheric Administration.
left, URI professor John Merrill, of North Kingstown, right with the balloon is URI
undergraduate student Kyle Murray of Johnston