Researchers have begun a massive study of thunderstorms and lightning in the Great Plains and Deep South to determine how much thunderstorms contribute to greenhouse gases.
The 45-day effort – called the Deep Convective Clouds and Chemistry project – involves more than 100 researchers from the National Oceanic and Atmospheric Administration and 29 other organizations. It will wrap up June 30.
Thunderstorms act like natural elevators: their updrafts hoist pollution and moisture-rich air to the upper atmosphere where they mix or chemically react in sunlight to produce ozone.
Ozone serves as a critical shield in upper levels of the atmosphere, shielding the Earth’s surface from harmful ultraviolet radiation, said Mary Barth, a scientist at the National Center for Atmospheric Research in Boulder, Colo. Ozone also can serve as an important cleanser of the atmosphere.
But at lower levels, Barth said, ozone is a pollutant and irritant.
“We’re not trying to change thunderstorms,” she said. “We’re just trying to understand the process, understand its role in the atmosphere.”
Thunderstorms are thought to be the largest natural source of nitrous oxide because lightning produces nitrous oxide. That chemical helps regulate the upper atmosphere but also is a pollutant at lower levels.
“We need to know what the natural levels are so we can better understand the man-made sources,” said Don MacGorman, a physicist at the National Severe Storms Laboratory in Norman, Okla.
The study will focus on three areas: northeastern Colorado, central Oklahoma and northern Alabama.
“Each of these regions have antenna stations to receive lightning information,” Barth said. “Since we have a network of these stations, we’ll be able to map out where the lightning is in the storm in three dimensions.”
Thunderstorms are unique in each of the three regions, officials say.
“In the High Plains of northeast Colorado, the storms will have a lot more ice in them compared to say, Oklahoma,” Barth said. “That region is at higher altitude.
“Alabama has a lot of trees, which emit hydrocarbons, so the environment is very different from what we see in west Texas,” she said. “This will give us a chance to examine different compositions of air and how do those hydrocarbons from forests contribute to the production of ozone in the upper atmosphere?”
The Great Plains is the stage for classic supercell thunderstorms, Barth said, while the Deep South commonly sees “pop-up” thunderstorms – storms that bloom from nothing to downpours in 45 minutes, then fall apart.
The study will include the use of airplanes loaded with weather instruments.
“One is going to fly low altitudes measuring what’s going into the storms, the second at higher altitudes, to see what’s coming out from the thunderstorms” in the upper levels of the atmosphere, Barth said.
The planes will be based in Salina and fly to wherever the storms develop.
MacGorman said he is excited about what the study can teach researchers about lightning.
“Lightning tells us there’s a thunderstorm there,” he said.
With additional knowledge about how lightning forms and propagates, MacGorman said, “that should help us a lot on forecasts” – particularly on the West Coast and in mountainous regions.