IN HIS ELEMENT
Ancell's NSF Research May Discover
How People Influence Weather

Written by Toni Salama

The Sway of a Storm

Never underestimate the power of a thunderstorm. It may unearth an artifact long buried or blow in a keepsake from the next county.

Then again, it just might stir a youngster’s heart to explore the forces that created it. That’s how it was for Brian Ancell, who grew up in the tempest-prone Chicago suburb of Evanston.

“When I was maybe 10 years old, I began loving the excitement involved with big thunderstorms,” Ancell recalls. “The way the sky darkened and the ominous mood that came about was fascinating, not to mention the sheer power of the storms themselves.  The storms were so powerful they had to be respected, and that’s what drew me in.”

Ancell, now an atmospheric scientist in the College of Arts & Sciences’ Department of Geosciences, may be on the verge of learning how human enterprise impacts the weather, thanks to a 5-year grant from the National Science Foundation. The NSF’s Faculty Early Career Development Award, or CAREER for short, recognizes and funds the research of top junior faculty nationwide.

His project, “CAREER: Quantifying Inadvertent Weather Modification and Education through Museum Programs,” will concentrate on measuring the effects of human activity on high-impact weather events.

"Essentially, we are well aware that human activities
can make relatively small local changes
to the atmosphere,” Ancell said.

He’s full of examples. For instance, heat generated by a large city—what Ancell calls the heat-island effect—makes the atmosphere above that city warmer, especially at night, because the concrete has retained the day's solar radiation. Irrigation is another case in point: Watering crops increases local humidity.

Other agricultural practices and the development of wind and solar farms, he says, change the land surface in ways that have the potential to modify the wind, temperature and moisture characteristics of the atmosphere close to the ground. 

Ancell’s job will be to study how those comparatively small influences may translate into serious weather changes elsewhere, several days later. But that’s just for starters. “Estimating how these effects are anticipated to evolve over the next century is also a goal of this work,” Ancell said.

His measuring rod will be the same weather-prediction model that meteorologists use to create the daily forecast. “It estimates the state of the atmosphere, say, right now, and then we let that state evolve on fast computers using equations that we know the atmosphere abides by, like conservation of momentum,” Ancell said.

“What I can do to measure the effects of an urban heat island, for example, is to run the forecast model twice, with the only difference between the two runs being the heat generated by the urban heat island,” he explains.

“By looking at how the two forecasts diverge in time, I can
estimate the effects of the urban heat island on the atmosphere
days later, and thousands of miles away,” Ancell says.
“That’s a bit simplified, but it’s really the basic idea.”

But anyone who has counted on a particular forecast knows all too well that it may not come to pass. Blame it on chaos.

“Chaos exists in physical systems like the atmosphere, and is essentially defined as small changes that grow over time to become large changes,” Ancell explains. This is the reason weather forecasting is not very accurate, even a few days out. “Our models of the atmosphere always contain small errors at the beginning of the forecast, just because we are estimating what the winds, temperatures, pressure, and so forth are all over the world.”

Ancell explains that those small errors compound over several days to become larger ones. As a result the standard five-day forecast often is flawed because, he says, “the modeled cold fronts, rain, high winds aren't where they actually will be in five days.” 

The Power of the Butterfly

One of the unknown quantities in those equations may be human activity: enter the “butterfly effect,” the theory, coined by meteorologist Edward Lorenz, that the flapping of a butterfly’s wings in one location today could influence a hurricane somewhere else in the future.

“So,” Ancell says, “the work I propose essentially puts a new twist on an old idea. The ‘butterfly’ is human activity, and the ‘hurricane’ represents weather patterns more generally.”

It’s all a matter of calculating—accurately—how the activities of human civilization influence the weather, how they change the dynamics of atmospheric temperature, wind and moisture fields. The forecast model will help him see how those changes play out over time.

“In addition to estimating the current-day effects of human activities on the atmosphere, I will need to estimate how these effects will evolve in the next hundred years,” Ancell explains. “Since the human inputs to the atmosphere depend on the nature of human activities themselves, this will involve estimating population and urban growth, how agricultural practices will change, and how the world will be generating energy in the upcoming century.

“Much of this will be linked to climate change, so climate prediction will play a role. Then I can use the same forecast model to investigate these estimated future changes,” he says. “That’s one aspect of this work I really find interesting—the integration of other disciplines such as climate science, agricultural science and even politics with atmospheric science.”

Beyond the Lab

Ancell’s NSF grant will include the creation of a museum exhibit in collaboration with the Museum of Texas Tech University and a “traveling trunks” component that will make the rounds of local schools and summer science camps. This part of his proposal was inspired by previous success at the Burke Museum, University of Washington.

“I really saw how the museum could influence kids in a positive way. They really viewed the museum as a very high authority,” he remembers. “My wife, Keely, also worked in the education office there, so we talked about museum education all the time, particularly the exhibits, general outreach activities and traveling trunks.”

Now a father of three, Ancell discovered the traveling trunks at the Burke Museum were a huge hit with local schools. “When the time came to write the educational component of my CAREER proposal,” he said, “I hatched the plans for the TTU Museum exhibit, traveling trunks and summer science camp without hesitation.”

Manage Ourselves, Manage the Weather?

At the moment, not much is known about human impact on weather patterns, Ancell says. Understanding that relationship is at the heart of his proposed work. That’s why he has taken up the research.

Ancell says there’s reason to expect that human activities, however unintentional, may alter thunderstorm activity, low-pressure systems, fronts and widespread precipitation.  

“If the consequences are significant, society should make responsible decisions on how to manage the activities that produce them in the first place,” he says. “In any case, I really want to teach people that what we do matters regarding the atmosphere, and hope that this might help future generations responsibly manage our environment.”