Researchers at the University of Toronto have identified the mechanism responsible for the formation of salinity and temperature “staircases” in the Arctic Ocean, resolving a mystery that has complexed oceanographers and climatologists for more than half a century.
Understanding how these vertical structures work promises to illuminate the causes and consequences of rapid Arctic sea ice loss from climate change.
“Our discovery of a new mechanism of hydrodynamic instability provides insights into the formation of staircase-like structures resulting from the mixing of warm salt water and cooler fresh water,” said lead author Yuchen Ma.
“These structures were first observed in the late 1960s but the mechanism responsible for their existence has never been explained,” he said.
Known as thermohaline staircases, these step-like variations of salt concentration and temperature are common in a wide range of regions of the global ocean.
“The ocean is typically thought of as a highly chaotic and turbulent environment, so it is striking to see such strongly defined layers of salt and heat within it,” said Ma.
The flow of heat out of the ocean into the sea ice above is strongly enhanced by the presence of thermohaline staircases. Therefore, understanding the staircase formation process in the polar oceans is important for developing future global warming projections and informing efforts to reduce sea ice loss.
https://phys.org/news/2022-09-mechanism-responsible-temperature-salinity-staircases.html