Scanning the Stratosphere
Ask Kennesaw State University environmental science professor Brent McDaniel for an extended …
Georgia (Jan 20, 2012) —
Ask Kennesaw State University environmental science professor Brent McDaniel for an extended weather forecast and you will probably get a blank look.
“I’m an atmospheric scientist, not a weatherman,” he says. “I don’t know what the weather will be like in two or three days. Our atmosphere is a chaotic system that regularly forgets itself so extended forecasts are little more than guesses.”
The Cobb County native originally planned to be a physicist and earned bachelor’s and master’s degrees in physics from Georgia Tech and Georgia State respectively, then returned to Tech to pursue a doctorate in atmospheric science.
“By the time I was ready to pursue a Ph.D.,” he says. “I had decided to transition into atmospheric science. It’s quite interesting to switch from physics to atmospheric science. I was way ahead of the curve in math, but way behind the curve from a weather point of view.”
For decades, traditional climatologists and meteorologists believed that the troposphere, the layer of the Earth’s atmosphere closest to the planet, was the only thing worth studying in terms of weather.
“The popular belief until the late 1990s was that what’s going on in the stratosphere — the second layer — didn’t affect the troposphere, thus it didn’t affect our climate,” McDaniel says. “Now we’re finding out that stratospheric changes do impact the troposphere directly and indirectly. In other words, the stratosphere matters. This is where my research comes in.”
McDaniel’s research has determined that tropospheric disturbances called Rossby waves, global disturbances in atmospheric pressure and winds, are produced where temperatures change dramatically and winds blow over varying Earth surfaces, such as major mountain ranges. Those waves can rise into the stratosphere and, if they produce enough energy, may result in stratospheric final warming, an annual event that marks the transition from winter to summer wind patterns in the stratosphere.
“Those Rossby waves have to go somewhere so they go up into the stratosphere,” he explains, “and just like ocean waves, they can only sustain themselves for so long before they crash and break, depositing energy into the stratosphere and raising its temperature. Normally, the stratosphere is kept warm by an ozone layer, but recently ozone depletion has been occurring, causing the stratosphere to cool. As the stratosphere cools, more ozone is destroyed, which causes further cooling, which causes more ozone destruction, and it becomes a vicious cycle.
“Meanwhile the troposphere responds to the stratospheric cooling by warming, contributing to global warming and, in opposition to the stratosphere, increasing ozone levels near the surface. Changing the balance of ozone from stratosphere to troposphere is bad for us. It affects our health, our food supplies, our planet itself.”
A major component of McDaniel’s research is being able to accurately predict when stratospheric final warmings will occur. “Right now there is zero predictability,” he says, “but by better understanding how the troposphere and stratosphere interact, we canimprove weather prediction and climate models. This will affect how well we understand global climate change and may help policymakers try to mitigate mankind’s impact on the planet.”
-- Neil McGahee
A leader in innovative teaching and learning, Kennesaw State University offers undergraduate, graduate and doctoral degrees to its nearly 43,000 students. With 11 colleges on two metro Atlanta campuses, Kennesaw State is a member of the University System of Georgia. The university’s vibrant campus culture, diverse population, strong global ties and entrepreneurial spirit draw students from throughout the country and the world. Kennesaw State is a Carnegie-designated doctoral research institution (R2), placing it among an elite group of only 6 percent of U.S. colleges and universities with an R1 or R2 status. For more information, visit kennesaw.edu.