Meteorologists long ago realized weather is nonlinear—or disproportionate in cause and effect. For example, an increase in temperature alters the system in more ways than just a higher thermometer reading.
But before the 1980s there was no systematic framework to help understand and predict such seemingly random atmospheric changes.
The early ’80s saw the emergence of chaos theory, which states that nonlinear systems—those that appear unpredictable and random, such as weather—actually operate within certain rules. As an assistant professor at UWM, Anastasios Tsonis was the first scholar to apply chaos theory to meteorology.
“I was a physicist by background, so I saw the potential,” he recalls. “It has led to much more improved predictions because the certain approaches from chaos theory were applied to the prediction problem. It’s standard procedure now.”
Tsonis and his postdoctoral fellow James Elsner took an approach to climate research that many of their colleagues at first rejected.
“In the early 1980s atmospheric scientists didn’t have a clue,” Tsonis says. “We were going to conferences and some of them were laughing when we were talking about these new ideas.The level of atmospheric scientists was not at that point where we could easily communicate what we were doing. It was too abstract for them.”
After they overcame fierce resistance from dissenters, a new paradigm in weather prediction was born. “Nonlinear models helped us understand the physics behind nonlinear prediction, which eventually resulted in methods to improve and extend (weather) prediction,” he says.
Tsonis has also done significant research in the area of global climate change. His major question has been, “How much of this change is natural variability and how much is man-made?”
Recently, his research team discovered a new mechanism in climate that can account for all the major temperature shifts in the 20th century. Based on this work, Tsonis’s team has been able to make a calculation of the effects of human activities on global temperature. While the research has not yet been published, Tsonis predicts, “This is going to make the news.”
Tsonis is credited with the development of UWM‘s Atmospheric Sciences Group, which he calls “one of the most productive groups in the university for its size.”
For much of his success, Tsonis credits the institution.
“UWM offered me a unique opportunity to do what I did,” he says, citing his freedom in assembling the research group and pursuing his interests. “I think if I were in a bigger university, I would not be able to do that.”