In 2020, as the COVID-19 pandemic disrupted lives worldwide, Greema Regmi began her Ph.D. in UMBC’s atmospheric physics program. Studying remotely from her home in Nepal, she navigated a grueling schedule due to the time difference.
“One class started at 1 a.m. Nepal time, and one final went until 4:30 a.m.,” she recalls. Yet, she embraced the challenge. “I didn’t mind. I like working at night, so it worked for me. And because of COVID, I had nothing else to do. At least this way, I was making progress towards my studies.”
Now in her fifth year, Regmi’s perseverance has earned her NASA’s prestigious Future Investigators in NASA Earth and Space Science and Technology (FINESST) fellowship, which will provide up to $50,000 annually for up to three years to fuel her research on atmospheric dust.
Regmi’s passion for atmospheric physics took root in Nepal. For an undergraduate project, she analyzed meteorological factors surrounding a tragic local plane crash. “Nepal has a lot of hills and mountains, so it channels wind in certain directions,” she explains. “Based on my analysis, unexpected turbulence could have been a factor in the crash.”
As a senior at Tribhuvan University in Kathmandu, Nepal, Regmi traveled to the U.S. for the first time, to present at the American Geophysical Union Annual Meeting. The event was a turning point in her scientific trajectory.
“I really liked sharing my work in front of a huge crowd. Everybody was listening, and that boosted my confidence,” she says. In Nepal, it sometimes felt like research was a lower priority, but the U.S. offered a fresh stage for her work, Regmi says: “The AGU meeting was great—people appreciated my work. That was a huge motivation to continue and do grad school.”
Decoding dust for climate science
Regmi’s FINESST-funded research aims to improve the accuracy of climate forecasting by refining how atmospheric dust is accounted for in climate models. How dust scatters light affects how much heat is reflected back to space versus absorbed. She combines data from LiDAR and multi-angle polarimeters, such as NASA’s Research Scanning Polarimeter, to analyze dust’s role.
“A polarimeter measures how much radiation you see from the top of the atmosphere,” integrating information from every atmospheric layer, “versus LiDAR, which gives you information on each layer of the atmosphere separately. So when you combine both of those, you have a very rich dataset,” she explains.
Regmi’s work challenges outdated assumptions. “Our existing models assume that dust has a simple shape, such as spherical, but for a long time we’ve known that it isn’t that simple,” she says. In her work, she models dust as hexahedral instead—a 3D shape with six faces. The most familiar hexahedron is a cube, but the angles can shift to make it more or less pointy.
Regmi was surprised by how much using a spheroid versus hexahedral model for dust affects the overall climate models she is investigating. “I did not expect the shape of dust particles that tiny to have such a huge impact. And that was very exciting for me,” she says.
Her research focuses on dust traveling across the Atlantic Ocean from the Sahara Desert. The solid, dark ocean background makes it much easier to pull out clean information about dust, avoiding uncertainty introduced by variegated background landscapes, like the shadows that form in mountain ranges or a wide range of vegetation colors. Improved climate models based on her work could inform decision-making related to climate resilience and mitigation.
A community that lifts you up
Regmi has been able to accomplish so much in part because of the supportive community she found at UMBC, after finally arriving on campus in fall 2021. Her Ph.D. advisor, Vanderlei Martins, professor of physics and director of UMBC’s Earth and Space Institute, fosters a collaborative lab.
“Vanderlei is a great professor, but what I really appreciate about him is the group that he has built over years. Everybody in the group is as supportive as he is,” Regmi says. “He has done so much in the field, yet he’s still so humble.”
The positive feelings are mutual. “From the very first classes it was obvious that Greema had great potential and tremendous enthusiasm to learn, to grow scientifically, and to work with others,” Martins says.
Regmi is co-advised by Reed Espinosa, Ph.D. ’17, atmospheric physics, a research physical scientist at NASA Goddard Space Flight Center. “He is an outstanding mentor—patient, thorough, and always encouraging,” Regmi says. “Most of what I know about conducting research I have learned from him.” And Espinosa learned much of that from Martins, who was his own Ph.D. advisor.
Pengwang Zhai, professor of physics, has been another mentor. “Regmi is a hardworking and intelligent student,” Zhai says. Despite starting her Ph.D. during the pandemic, “she embraced the difficulties, overcame steep learning curves, and has grown into a valuable member of the atmospheric physics program.”
Martins highlights her cohort’s strength. “Regmi has joined an enthusiastic group of Ph.D. students in the atmospheric physics program at UMBC, who have clearly shown that together we are better, and can go farther,” he says.
Regmi values the camaraderie. “In Vanderlei’s group, people help you in every way they can,” she says. Her office near the elevator sparks connections. “Every time someone comes up, they will stop to say ‘hi.’ I’ve made a lot of friends and learned so much from them,” she shares. “I like my department a lot.”
Bridging two worlds
Regmi’s journey bridges her unique perspectives as a student in Nepal and the U.S. “You learn different things when you work back home in a developing country. And when you come here to a developed country, it’s a very different perspective,” she reflects. “In Nepal, it’s more about, ‘These are the resources we have, so how can we make the most out of them?’” she says. At UMBC, she’s embraced broader opportunities. “I think here you can push the limit. I don’t even know what the limit is in the U.S. Here you can dream more and be more experimental,” she observes.
Regmi is inspired by her father, also an atmospheric physicist, but she has forged her own path. This spring, she returned to Nepal for only the second time since starting her Ph.D. to conduct research with him. “I finally got to work with him professionally, which was great,” she says.
Grounded in the UMBC physics department’s community of support, Regmi’s confidence has only grown since her arrival in Maryland. “There’s always a place for my opinion, which is very nice. Because of that, and all of the experiences I’ve had, now I have the confidence to start my own project,” she explains. “And that’s why I think now I’m confident to go back home, lead something there, and be helpful in some small way.”
Learn more about atmospheric physics research at UMBC.
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