True story: Baylor Fox-Kemper’s Ph.D. adviser’s adviser’s adviser’s adviser was Heinrich Rudolf Hertz, the namesake of the unit of cycles per second. That’s Hertz, as in “My new PC has a quad-core 2.6 gigahertz processor.”
Because the new assistant professor of geological sciences creates computer models that account for the role of ocean motions on climate change, he uses considerably more gigahertz than that. In fact, this fall he plans to begin running some new simulations on a National Center for Atmospheric Research supercomputer that’s just come online in Wyoming. It has 74,592 processor cores and therefore performs 1.6 thousand trillion operations per second. That’s a lot of hertz.
“We’re going to try to do a series of simulations that resolve all the way from the tens of kilometers of ocean scale down to just a couple of meters,” he said. “The goal is to resolve all of the things that are going on in the upper ocean to get a handle on how they interact with each other.”
The things of greatest interest are the heat and carbon dioxide that the ocean absorbs from the air through its surface. Waves, winds, and heat drive the turbulence of the ocean on the meter scale. Over kilometers, the ocean’s swirling eddies are driven by differences in density that arise from variations in temperature and salinity. These eddies inhibit heat and carbon dioxide absorption. Turbulence promotes it.
Making sense of the process, as Fox-Kemper hopes his simulations will, is vital to studying climate change. Just like the atmosphere, the ocean has a huge influence that scientists need to understand if they hope to properly predict how much warming has yet to occur and how fast it will happen.
The particular role the oceans play is in how they govern the long-term progression of global warming.
“The atmosphere doesn’t have a great memory; it’s a chaotic system,” said Fox-Kemper, who will come to Brown in January from the University of Colorado–Boulder. “Weather phenomena stop being predictable after a little bit over a week. In the oceans, on the other hand, the currents are slower, the processes are larger and so the time scales are longer. If we want to understand what happens on time scales longer than a week, then the oceans become an important part of the process because they are the memory of the system.”
Fox-Kemper is not coming here from landlocked Colorado because Rhode Island is “The Ocean State,” although the move marks his return to New England. He earned his Ph.D. in physical oceanography at MIT/Woods Hole Oceanographic Institute and his master’s in physics at Brandeis.
Instead, the physicist who has been doing research and teaching in an ocean and atmospheric sciences department has come back to this area’s rocky shores to be among geologists and geology students.
“I like operating with small groups of very dedicated students,” he said. “I like the connection with geology because of the slow time scales of the ocean. Joining a geology department, where people are working to reconstruct past ocean circulations, is an ideal connection.”
At Brown, where interdisciplinary barriers are generally low and climate change research is rapidly evolving rather than ossified, Fox-Kemper sees opportunities for broad-based potential collaborations, too.
“You can jump in, in a much more modern setting, and have connections between biology, and chemistry, and physics, and atmospheres and oceans, and ice in a way that departments that traditionally treated those things as separate don’t have ready access to,” he said.
And yes, even if just for inspiration, he’ll again have ready access to an ocean as well.