Seawater synergy

Three years ago, Carlyn Schmidgall joined a dozen other researchers aboard a ship off Nome, Alaska, to collect high-resolution data that could reveal small-scale processes with big implications for the Arctic Ocean and sea ice.

“These processes occur on such small scales that they’re essentially missing from all but the most high-resolution of (earth system) models,” says Schmidgall, a physical oceanography Ph.D. student at the University of Washington.

The team deployed autonomous devices to sample seawater and attached devices to the ship’s reels to collect continuous meteorological and ocean data. Every kilometer or so, Schmidgall and her colleagues lowered sensors to measure temperature, pressure and salinity. At dusk, Schmidgall, took in deck views that paired the endless expanse of blue and scattered ice, as cotton-candy skies faded into darkness.

“That’s a memory that motivates my work,” says Schmidgall, whose marine connections run deep. She grew up near Seattle and spent summers in Oregon at a family beach house. The ocean serves as both playground and ecosystem — something to enjoy and something worth protecting.

As an undergraduate at the University of California, Los Angeles, Schmidgall expected to apply her math and science interests toward engineering. But when she took introductory courses in atmospheric and ocean sciences, Schmidgall realized how deeply tied the fields were to human welfare.

The ocean and atmosphere “are two very interconnected systems.” In the Arctic, for instance, coastal Indigenous communities depend on stable sea ice for protection from coastal erosion and storms and for their traditional ways of fishing and whaling.

Schmidgall’s Ph.D. research, advised by Peter Gaube and LuAnne Thompson, zeroes in on how Pacific water entering through the Bering Strait carries heat into the Arctic and “where that heat goes, where it’s stored, and how it impacts the ice conditions and atmosphere.”

As a Department of Energy Computational Science Fellow, she has combined insights from her Arctic observations with global simulations to get a complete picture of these processes.

During a fellowship practicum at Los Alamos National Laboratory, Schmidgall employed high-performance computing and the DOE’s Energy Exascale Earth System Model (E3SM) to simulate Arctic Ocean circulation. She used tracers — the numerical equivalent of dye droplets in water — to study the movement of water masses, she says, for “changes year to year and how we can better understand the pathways since they impact the dynamics of the ocean as a whole.”

The practicum experience allowed her to learn how to design and carry out these global simulations and opened up a range of new questions that she could answer in her research. The Los Alamos experience afforded her a much broader look at the Arctic system and its dynamics, she says. “I have gotten excited about the degree of creativity you have when you’re using models to study the ocean.”

She also appreciates how the large-scale simulations complement the fine-resolution data she collected aboard the research vessel. Each provides “important ways to understand the ocean and climate, and how we expect them to change in the future.”

Schmidgall is passionate about sharing that knowledge with others. In the Seattle area, she has volunteered as a naturalist on tidepool treks and on whale-watching expeditions.

After completing her Ph.D., Schmidgall hopes to find a role that combines research with telling people “about all these amazing parts of our planet and why we should care about them.”