Principal Investigator - Sylvia Sullivan

Sylvia is an Assistant Professor at the University of Arizona since January 2022. She has spent time as a fellow at the Karlsruhe Institute of Technology and a postdoctoral researcher at Columbia University. She earned her doctorate from the Georgia Institute of Technology in 2017 and her bachelors from the California Institute of Technology in 2012, both in chemical engineering with concentrations on earth and environmental sciences. In her free time, she enjoys running, reading, watching movies, and learning languages.

Contact: sylvia_at_arizona.edu

Sylvia’s CV

Doctoral Student - Thabo Makgoale

Thabo is a fifth-year Ph.D. student in Hydrology & Atmospheric Sciences, focusing on the effect of ice microphysics within tropical mesoscale convective systems using storm-resolving simulations. Mr. Makgoale is both a NASA FINESST awardee and Carsons Scholar and worked as a research scientist in Climate Change and Variability for almost 7 years at the South African Weather Services (SAWS). He completed his Bachelors degree in Ocean and Atmospheric Sciences in 2012 and his honours degree in Atmospheric Sciences in 2013, both from the University of Cape Town through the Climate System Analysis Group (CSAG). He completed his Masters degree in Geography and Environmental Management at North-West University (NWU) in 2021 with a thesis investigating the sensitivity of simulated temperatures in climate models to aerosols over southern Africa.

Contact: temakgoale_at_arizona.edu

Doctoral Student - Edgardo Sepúlveda Araya

Edgardo is a fifth-year Ph.D. student in Environmental Engineering, focusing on the polarized radiative transfer simulations of ice clouds and the radiative effect of cloud ice optics schemes in storm-resolving simulations. He was a Herbold Fellow and received the 2025 1st place AMS Student Award for Oral Presentation. Before joining us, he worked as an Associate Researcher in the Antarctic Research Group in the Department of Physics at the University of Santiago of Chile with interest in climate change impacts in Chile and Antarctica. He received his Bachelors in Applied Physics in 2015 and his Diplom in Physics Engineering in 2021, both from the University of Santiago of Chile. Over the last 6 years, Edgardo has been involved in a series of field campaigns from the Atacama Desert in northern Chile to Union Glacier in Antarctica, with studies focused mainly on UV radiation, the Antarctic ozone hole and radiative effects of clouds on the Antarctic Peninsula. Edgardo spends most of his free time playing music and listening to different styles of music, jazz being one of his favorites.

Contact: edgardo_at_arizona.edu

Doctoral Student - Juliana Mejía Sepúlveda

Juliana is in her fourth year of the Ph.D. program in Environmental Engineering. She is interested in interactions of extreme heat and poor air quality episodes (aerosol extreme events) for the U.S. Southwest but also other regions. Juliana was a George \& Dixie Shirley Graduate Fellow and an organizer of the IGAC Early Career Research Online Conference. She is also a talented experimentalist and has helped build our lab space, perfoming frozen droplet assays in her first few years. Juliana is originally from Colombia and joined us from SIATA, the Early Warning System of the Aburrá Valley. She received her Environmental Engineering Bachelor and Masters degree from the University of Antioquia. She joined different projects associated with heterogeneous photocatalysis using titanium dioxide and chemical characterization of PM10. Juliana is an animal lover, taekwondo blue belt, enjoys hiking and is passionate about astronomy.

Contact: julianamejia_at_arizona.edu

Doctoral Student - Ashlynne Gary

Ashlynne is in her second year of the Ph.D. in Atmospheric Sciences, working toward completing her M.S. in spring 2027. She is interested in the effect of ice microphysics and cloud-radiative heating on tropical cyclone intensification with additional interests in wildfire research and exoplanets. She attended the DOE Big Data Summer School earlier this year. She finished her B.S. in Atmospheric Science and Planetary Sciences in Spring 2025 at Purdue University where she did research on exoplanet cloud microphysics. She was an intern at the NOAA Storm Prediction Center in summer 2024, constructing wildfire climatologies, and was part of Purdue University’s Meteorological Association over the past few years. In her free time, she enjoys reading, hiking, dancing, and playing piano.

Contact: aogary_at_arizona.edu

Doctoral Student - Yerim Seok

Yerim is in her first year of the Ph.D. program in Environmental Engineering. She is interested in ice cloud microphysics, cloud dynamics, and cloud radiative effects and will contribute to polarized radiative transfer calculations as part of our NASA CHIRP collaboration. She completed her Bachelor’s and Master’s degrees in Climate and Energy Systems Engineering at Ewha Womans University in South Korea (B.S., 2024; M.S., 2026). During her master’s studies, she conducted research on clouds and atmospheric radiation using geostationary satellite observations over the Pacific Warm Pool. She also contributed to the development of cloud retrieval algorithms for satellite-based photovoltaic forecasting. In her free time, she enjoys watching movies and documentaries, journaling, swimming, and traveling.

Contact: yerims_at_arizona.edu

Master’s Student - Zach Powers

Zach is currently in his fourth year of the Bachelor’s program and first year of the Accelerated Master’s Program in Chemical Engineering. He is supporting our NASA CHIRP project by experimentally nucleating and growing ice crystals of certain morphology from relevant atmospheric solutes within our cryogenic microscope.

Contact: zpowers2_at_arizona.edu

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Former Group Members

Undergraduate Student - Giorgia Melita - Finishing fourth year of B.S. in Chemical Engineering at the University of Arizona

Undergraduate Student - Savanna Prentice - Chemical Engineer at Freeport McMoran, Miami, AZ

Undergraduate Student - Gracee Spatz - Finishing fourth year of B.S. in Chemical Engineering at the University of Arizona

Undergraduate Student - Hannah Golden - Chemical Engineer at Fairlife, Phoenix, AZ

Undergraduate Student - Linda Engelman - Environmental Engineer at Baxter & Woodman, Austin, TX

Undergraduate Student - Tanmay Agrawal - Master’s Student in Computer Science at the University of Arizona

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Group Principles

Our research group is guided by the following principles:

1. Curiosity – Questions, especially fundamental ones, are always welcome, and we do not dismiss new ideas without thought. Question-asking and openness to different perspectives are the ways in which we grow intellectually.

2. Inclusivity – Building a group of people with different backgrounds is important to us. Diversity of thought and experience not only generate more interesting ideas but also help us to circumvent confirmation bias.*

3. Collaboration – Along similar lines, our culture is collaborative not competitive. Asking for help and feedback is strongly encouraged when others’ time is respected. We actively seek to work with others and give credit where credit is due.

4. Communication – We want to be communicative about our scientific results – within the immediate group, the larger scientific community, and the broader public – but also when interpersonal conflicts arise.

5. Rest - Research is a creative endeavor, and rest is crucial to foster this creativity. It is important to take time off. Prioritization and saying no respectfully are important skills to learn.

6. Reproducibility – Especially as the volume of research output expands, it is essential that our results be reproducible. We value high-quality work performed more slowly and methodically over high-quantity work performed more quickly and sloppily.

* “If you put individuals together in the right way, such that some individuals can use their reasoning powers to disconfirm the claims of others, and all individuals feel some common bond or shared fate that allows them to interact civilly, you can create a group that ends up producing good reasoning …. This is why it’s so important to have intellectual and ideological diversity within any group or institution whose goal is to find truth.” Jonathan Haidt, The Righteous Mind