“Some of the most fundamental and complex research problems in climate and weather centers on our poor understanding of basic properties of clouds and and our inability to determine quantitatively the many effects cloud and precipitation processes have on weather and climate.”
Recipient of the 2022-23 Distinguished Alumni from ATMOS, Nesbitt leads a research group that makes stunning observations of the troposphere. These include the remote sensing of precipitation using radar and passive microwave sensors as well modeling of cloud dynamics and microphysics, land-atmosphere interaction, as well as data science and high-performance computation.
The uncertainty is complicated by global warming. “In the future,” he says, “my goal is to continue to contribute important advances in this area as the complex challenges that involve flows of water and energy through the earth system.”
A native of the snow belt, Nesbitt first took an interest in the weather as a nine-year-old when he would slide off the roof of his parents’ house into massive snow drifts. Transfixed by the Weather Channel he called the local NWS bureau on his own and asked for a tour. They complied. Many years later, mentored by Ed Zipser at Texas A&M, Nesbitt followed him to Utah when the storied observational meteorologist accepted a position at the U. Nesbitt earned his own PhD in 2003.
“You get goosebumps,” Nesbitt says about his current work at the University of Illinois Urbana-Champaign where he is the associate head and director of graduate studies. “When you go out and plan an experiment about the things that already excite you and collect data with these amazing instruments to quantify how these things work, I sometimes pinch myself: how do I get paid to do this?”
This kind of research has come a long way since the ‘90s. Nesbitt recalls the five to six hours it took to read one summary report off of magnetic tapes from NASA’s first satellite-derived data. “We had no idea what we’d see,” he says. No longer were they only seeing pictures but vertical x-rays inside of clouds. Of course, twenty of those tapes he and his team painstakingly read back in the day could now be stored on an iPhone. Even so, “it was a real breakthrough,” Nesbitt says of satellite technology.
NASA also funded major field campaigns to validate what data researchers were studying from satellites. A U2 spy plane was converted into research aircraft and piloted at seventy thousand feet to probe through storms, collecting visual and hands-on experiences as corroboration. Technology has not only assisted Nesbitt in collecting data, but analyzing it through sophisticated artificial intelligence models to predict impacts from large data sets with large uncertainties.
In Cordoba, Argentina the uncertainties of storms have real-life consequences–just as they do in Buffalo, where last December, lake-effect snow and wind combined in an unusually catastrophic combination. Nesbitt and collaborators were funded $20 million to stage the largest land-based field campaign effort ever conducted outside of the U.S. in the atmospheric sciences. They set up observation sites and dispatched radar trucks (that decades ago inspired the movie “Twister”) on the eastern foothills of the Andes where thunderstorms develop rapidly, some of them twenty-one kilometers tall with an updraft chimney fifty kilometers wide. The confluence of data from multiple dimensions allows for greater predictability of future weather events even with the chaotic nature of convective storms. The impact of global warming on precipitation processes remains a critical research area, and Nesbitt’s work is at the center of that.
Nesbitt’s time in Utah was complemented by the 2002 Winter Olympics. “It was a really exciting time,” he says, remembering the weather observing ATMOS did for the games as well as the invitation to see the dress rehearsal of the opening ceremonies. And then there was the lake-effect snow stemming from the Great Salt Lake though not quite as extreme as Buffalo’s. He learned to ski and found faculty members’ passion for Utah’s winter sports and the “interesting weather” along the Wasatch Front infectious. He also married a local.
Of late, Nesbitt has trained his sights on the representation of ice clouds, which produce the majority of earth’s precipitation, yet are the most difficult to simulate and observe due to their complex microphysical nature.
Steve Nesbitt’s arrival in Salt Lake earlier this year to accept his award was a homecoming in multiple ways. He got to experience again the campus and its setting which first “sold” him on attending the U. It validated the work he’s been engrossed in ever since he slid off the roof into those Buffalo snow drifts. It was also a reunion of many fellow atmospheric scientists.