UMD Undergraduate Research Journal

Up in the Air: the adventures of Prof. Jeffrey Stehr

by Abigail Ahlert

Stehr with two graduate students, Heather Arkinson and Lacey Brent, at the NASA Langley Research Center.

Upon arriving at the office of Professor Jeffery Stehr, I was not at all surprised when the first thing he asked me was, "So how are you enjoying the Maryland weather?" If anyone is willing (and, indeed, excited) to talk to me about weather, it would be this professor of atmospheric science.

Stehr received his graduate degree in physics from the University of Michigan, and is currently the associate director of the brand new undergraduate Atmospheric and Oceanic Sciences (AOSC) program at the University of Maryland, College Park. He plays an active role in promoting and conducting research with the help of both graduate and undergraduate students while building the foundation for a new major.

Stehr's research is primarily focused on air pollution and atmospheric chemistry, and his team currently holds a contract with the Maryland Department of the Environment. Their goal is to use measurements of different chemical compounds collected from a small private airplane at different positions and altitudes to model the composition of the atmosphere with more detail and accuracy than others have before. "The idea there is, with this small airplane you can get into these tiny little airports and get all the way down to the ground, then spiral up. By getting that profile with all those measurements, you get to really challenge the model in a way that it's not used to being challenged," Stehr said. "Most of the [original] models have been evaluated with surface measurements. Those will tell you a lot - and are relatively cheap compared to what we're doing - but they really can't tell you what's going on aloft."

Stehr and his team take the plane up on hot days in the summer, when air quality can vary dramatically. The plane heads west or south of Washington, D.C., depending on the wind direction that day. As it flies, eight different instruments measure the amounts of carbon monoxide, sulfur oxide, ozone, particulate matter and nitrogen dioxide in the air. The instruments also take readings of current temperature, relative humidity and air pressure.

These flights have been taking place for multiple years now, and the data is consistent, yet surprising. "By flying in spirals out over the mountains to the west, we can see that we have this [pollution] coming over the mountains that wasn't in the model, and that was a significant fraction of our problem," he said. Stehr and his group of graduate students estimate that about 30-50% of the pollution in Western Maryland is coming from the Appalachian Mountains and the Ohio River Valley, primarily from its industrial and automobile emissions.

Dr. Jeffrey Stehr

In addition, Stehr is also involved in the Linear Comparison Campaign with the National Aeronautics and Space Administration (NASA). Last summer, Stehr's group took their small plane and equipment around the outskirts of Washington D.C., while a NASA P3 plane took concentration readings within the metropolitan area. The planes were flown at the same time as a satellite taking the same measurements passed overhead. The data was compared and used as part of a NASA project to improve satellite readings of atmospheric conditions.

These affiliations and the results of their research are extremely relevant to areas along the East Coast, especially Washington, D.C. "We are pretty ideally situated to get transport from the Ohio River Valley. On high air pollution days, you can see the way it sets up and just comes right over the mountain," Stehr said.

While Stehr has extensive experience researching atmospheric chemistry, he now has a new role as the Associate Director of Undergraduate AOSC. This major spans multiple different topics, including meteorology, climatology, marine science, atmospheric chemistry and atmospheric physics. Though the major is new to Maryland, the AOSC department is not. It started off as part of a research institute that still exists today - the Institute for Physical Sciences. "At some point they realized that they had a bunch of dynamical modelers, who were really meteorologists, and they broke off and formed their own department," Stehr explained. After the department was created, graduate students were soon incorporated, and now, after years of battling for support and funding, the undergraduate program has, too, been approved.

The University of Maryland, College Park, is currently the only school in the state to offer an AOSC undergraduate degree. However, it is an increasingly popular field. According to the Bureau of Labor Statistics, employment of atmospheric scientists is projected to increase by 15% over the next 10 years. "This is a major where you can actually go out and get a job," Stehr said. "You can get a job with a bachelor's degree in this major, and in physical sciences, that's kind of tough to come by."

Due to multiple political and economic interests, the Department of Agriculture, NASA, reinsurance firms and consulting firms have all found weather data to be a necessary factor in their work. Stehr believes that climate change is undoubtedly playing a role. "People want to know what's going on with climate change, whether they believe it's going on or not...you need to know what's happening," he said.

With concerns of climate change as a continuously controversial topic, demands for scientific explanations and solutions are high. Between conducting air pollution research and playing a large role in Maryland's addition of the new undergraduate major, Stehr and the AOSC department are doing all they can to not only search for answers, but set the stage for future climate research.