An international team of scientists has discovered for the first time direct evidence linking seemingly random weather systems in the ocean to global climate. The research team, led by Hussein Aluie, an associate professor in the University of Rochester's Department of Mechanical Engineering and a scientist in the university's Laser Energetics Laboratory, reported their findings in the journal Science Advances.
This illustration by Benjamin Storer shows ocean weather systems (mesoscale eddies) overlaid with atmospherically driven climate-scale ocean currents (black lines). The image shows how these ocean weather systems are activated (red) or weakened (blue) as they interact with climate scales, in patterns that mirror global atmospheric circulation. Image source: University of Rochester/Benjamin Storer
Lead author Benjamin Storer, an associate researcher in Arue's Turbulence and Complex Flows Research Group, said weather patterns in the ocean are similar to those we experience on land, but on different time and length scales. Weather patterns on land may last several days and be about 500 kilometers wide, while ocean weather patterns, such as eddies, last three to four weeks but are only one-fifth the size on land.
"Scientists have long speculated that these ubiquitous, seemingly random movements in the ocean communicate with climate scales, but it has been obscured because it was unclear how to break apart this complex system to measure their interactions," Aroui said. "We developed a framework that does exactly that. What we found is different from what people expected because it requires atmospheric conditioning."
The team's goal is to understand how energy is transferred throughout the Earth through different channels in the ocean. They used a mathematical method developed by Arui in 2019, which Storr and Aroui subsequently implemented into high-level codes, allowing them to study different modes of energy transfer from the Earth's circumference to 10 kilometers. These techniques were then applied to ocean data sets from advanced climate models and satellite observations.
Research shows that ocean weather systems are both stimulated and weakened when interacting with climate scales, in a pattern that mirrors global atmospheric circulation. The researchers also found that an atmospheric zone near the equator called the Intertropical Convergence Zone produces 30% of global precipitation, causing massive energy transfers and creating ocean turbulence.
Studying such complex fluid motions occurring at multiple scales is no easy task, Stoll and Arui said, but it offers advantages over previous attempts to link weather to climate change. They believe the team's work provides a promising framework for better understanding the climate system.
"There's a lot of interest in how global warming and a changing climate affects extreme weather events," Aroui said. "Typically, such research efforts are based on statistical analysis and require large amounts of data to have confidence in uncertainties. We are taking a different approach based on mechanistic analysis that alleviates some of these requirements and allows us to understand cause and effect more easily."
Compiled from /scitechdaily