NASA selected a team of Georgia Tech researchers — Rong Fu, Yuanlong Hu, Yuhang Wang, Derek Cunnold and Greg Huey — from the School of Earth and Atmospheric Sciences to analyze Aura's data.

A month later, the Tech researchers were among the first to see the scientific data that arrived from space.

"The data received at the Jet Propulsion Laboratory was sent directly to us," Fu says. "We were able to begin our research focusing on high-altitude transport of water vapor — the most prevalent of all greenhouse gases and a key suspect in global warming.

"We found evidence that high-altitude thunderstorms can transport a large percentage of water vapor and a significant amount of carbon monoxide into the stratosphere over the Tibetan Plateau region."

The researchers found the vapor above the Tibetan Plateau, a mountainous area encompassing China, Tibet and northern India, was rapidly heating as it absorbed more sun radiation, creating what meteorologists call a convergence.

"Rising subtropical air rushes into the troposphere bringing particles, including water vapor and pollutants," Hu says. "As the air mass increases, it slows and the air in the rear catches up or converges. To avoid more compression, the air moves vertically, transferring the polluted air to the stratosphere.

"Stratospheric currents move horizontally so water vapor is transported to the polar regions, where it undergoes a chemical reaction that results in ozone depletion." Hu says the amount of stratospheric water vapor has decreased since 2000, but "what is up there now will still be around in 40 years."

To determine if the ozone layer is recovering, Cunnold must first go to the stratosphere. "We use Aura to measure the ozone content in the stratosphere," he says. "Then we calculate total atmospheric ozone. When you subtract stratospheric ozone from the ozone in the total atmosphere, you end up with a measurement of tropospheric ozone.

"It's a little early to identify trends, but our findings show the ozone layer is slowly recovering due to the Montreal Protocol in 1987, which banned the use of chlorofluorocarbons such as spray can propellants or refrigeration gases."

When greenhouse gases undergo changes, it can upset the atmosphere's heat balance and alter the climate, so it is essential to measure the gases in order to understand climate change, Hu says.

"The atmosphere has no boundaries, so pollution can move great distances across oceans and continents," Hu says. "Air quality has degraded due to surges in population and industry, like that occurring in China and India, and become a global health issue."

Hu says Aura can explore the atmosphere's natural variations as well as human activity to better predict changes on Earth.

Fu says she is very concerned about the atmospheric health of the planet. "If the amount of water vapor continues to increase in the stratosphere, it will speed ozone destruction, causing further global warming and notable changes in subtropical climates," she says. "Areas that are marginally habitable now will become uninhabitable if conditions worsen."

She says while it is possible to modify weather through environmental engineering, artificial changes often result in unanticipated consequences.

"We can't really change the behavior of weather," Fu says. "We must change people's behavior."

©2006 Georgia Tech Alumni Association