A Polar Plunge in Summer: Studying the Dynamics of Glacial Lakes

Anthony Mohr, COL ’24, Louisville, KY

There are many uncertainties in our understanding of the natural world, particularly in the regions less explored by humans—for example, the ocean, deserts, and ice sheets. Researchers are working diligently to identify the physical mechanisms that underlie important natural processes. This summer, I had the opportunity to join this research and get a taste of what a career in research could mean for me.

I worked in the Geophysical and Environmental Flows Laboratory (GEFLOW) in Penn’s Department of Earth and Environmental Science. With the help of my PI, Dr. Hugo Ulloa, and the other lab members, I studied the fluid flows of supraglacial lakes. Supraglacial lakes are lakes that form on top of glaciers, typically due to surface melting. Their effects are not yet entirely understood. For example, they likely contribute to hydrofracturing, breaking apart glaciers and dumping land ice into the ocean. While there exist one-dimensional models of supraglacial lakes that consider factors such as solar radiation, longwave radiation, and precipitation, my task was to create two-dimensional fluid dynamical simulations to see if there is more at play. I learned how to use Dedalus, a spectral solver for partial differential equations that is typically used for fluid dynamics. I also gained experience employing good software practices and using Penn’s high-performance computing resources.

Supraglacial lakes are interesting from a fluid dynamical perspective since they can contain significant convection. A famous type of convection in fluid dynamics is Rayleigh-Bénard convection. This is typically performed in a laboratory by heating the bottom plate of a tank of water so that the water at the bottom becomes less dense than the water above it. Eventually, overturning cells form, and the water is energetic and mixed. In glacial lakes, one can observe a similar type of convection. The bottom layer is actually cooled since these lakes form on ice. However, in very cold temperatures, the density of freshwater actually increases with temperature, so once again, the water at the bottom becomes less dense, and cells form. Supraglacial lakes are very active, and running direct simulations of them has allowed me to better identify important features such as the heat transfer with the ice layer. My work is in progress, but I hope to compare my findings with previous results from one-dimensional models on supraglacial lakes. I also hope that my research can better explain how these lakes evolve over time and cause fracturing and weakening of the ice.

My experience this summer has reassured me that I should pursue research in the geophysical sciences beyond graduation. It has also allowed me to become more familiar with all the aspects of conducting research: how to read scientific literature, deal with occasional hiccups, communicate my findings, work as a team, and ask important questions. I would like to continue my studies in the form of an honors thesis for the physics major. I am thankful for Career Services and the team at GEFLOW for this opportunity.

This is part of a series of posts by recipients of the 2023 Career Services Summer Funding Grant. We’ve asked funding recipients to reflect on their summer experiences and talk about the industries in which they spent their summer. You can read the entire series here

By Career Services
Career Services