The El Niño climate pattern, when it occurs, presents as warmer-than-usual water in the equatorial region of the Pacific Ocean. The changes in temperature and rainfall that ensue from this warmer water can affect natural disasters, crop yields and even the proliferation of disease — but El Niño’s variations can be hard to predict. Recently, researchers at the University of Texas at Austin applied supercomputing power from the Texas Advanced Computing Center (TACC) to study these variations.
“Much of the world’s temperature and rainfall is influenced by what happens in the tropical Pacific Ocean where El Niño starts,” explained lead author Allison Lawman, who obtained her PhD at UT Austin and is now a postdoctoral researcher at the University of Colorado, Boulder. “The difference in rainfall between greater or fewer strong El Niño events is going to be a critical question for infrastructure and resource planners.”
The researchers sought answers through an array of climate simulations performed on TACC’s Lonestar5 system, a 1.2-peak petaflops Cray XC40-based supercomputer that launched in 2016 and ended production in 2021. Lonestar5 has since been succeeded by Lonestar6, which was unveiled in late 2021 and which delivers around three peak petaflops.
The researchers were specifically interested in whether anthropogenic climate change would cause significant changes in El Niño. They studied this by simulating El Niño over a prehistoric 9,000 year period where the main influences on the Earth’s climate were just the Milankovitch cycles, long-term shifts in the Earth’s axis, obliquity and precession.
They found that over this period, El Niño did intensify, but that its inherent variability easily drowned out these intensifications. “It’s like trying to listen to soft music next to a jackhammer,” said coauthor Jud Partin, a research scientist at the University of Texas Institute for Geophysics.
Now, the researchers are looking to gaze further back in the record — back to ice ages where the climate changes were more extreme — to see if those stronger climatic shifts induced stronger shifts in El Niño, as well.
“Scientists need to keep pushing the limits of models and look at geological intervals deeper in time that could offer clues on how sensitive El Niño is to changes in climate,” said co-author Pedro DiNezio, an associate professor at University of Colorado, Boulder. “Because if there’s another big El Niño it’s going to be very hard to attribute it to a warming climate or to El Niño’s own internal variations.”
To learn more about this research, read the reporting from the University of Texas at Austin here.