Researchers identify mechanism responsible for temperature and salinity 'staircases' in Arctic Ocean

A mystery that has puzzled oceanographers and climatologists for more than 50 years has been solved by researchers at the University of Toronto.

Understanding how these structures work will shed more light on the causes and consequences of sea ice loss.

Yuchen Ma is a graduate student in the department of physics in the Faculty of Arts and Science.

The mechanisms responsible for their existence have never been explained.

These step-like variations of temperature and salt concentration are known as thermohaline staircases.

A previous analysis by the same authors that documented the existence of this new instability was published in the Journal of fluid mechanics in 2020. To better understand global ocean circulation, a series of numerical simulations of turbulence were designed.

Ma says it's striking to see the layers of salt and heat in the ocean.

thermohaline staircases increase the flow of heat out of the ocean into the sea ice. Understanding the staircase formation process in the polar oceans is important for the development of future global warming projections.

"In this era of global warming, it is a well-recognized fact that the loss ofArctic Ocean sea ice cover is a critical aspect of this global process," said University Professor W. Richard Peltier, who is a co-author of the studies.

The ocean component of the climate models used to make projections of the global warming process are not able to resolve the staircase formation process.

The research focuses on understanding global ocean circulation under the ice age conditions.

The model showed that the rapid transitions from cold to warm weather were caused by a hole in the sea ice in the North Atlantic Ocean. The magnitude of the heat flow was determined by the assumption that there was a staircase below.

More information: Yuchen Ma et al, Thermohaline-turbulence instability and thermohaline staircase formation in the polar oceans, Physical Review Fluids (2022). DOI: 10.1103/PhysRevFluids.7.083801 Journal information: Journal of Fluid Mechanics