IBS Center for Climate Physics
Unveils Future Changes in Polar Oceans
Through Ultra-High-Resolution Simulations
As global warming accelerates, polar sea ice is melting at an unprecedented rate.
As a result, scientific analysis suggests that ocean currents are becoming more unstable and horizontal disturbances in polar oceans will intensify further.
The research team reported on November 6 that, using ultra-high-resolution Earth system model simulations, they found that anthropogenic warming rapidly melts sea ice and accelerates "mesoscale horizontal stirring."
"Mesoscale horizontal stirring" refers to the large-scale mixing of seawater caused by winds, ocean currents, and eddies.
On scales of tens to hundreds of kilometers, seawater mixes horizontally, transferring heat and nutrients, and affecting the entire ecosystem and environment, including plankton, fish eggs, larvae, and microplastics.
The researchers utilized the IBS supercomputer "Aleph" and the ultra-high-resolution coupled climate model CESM-UHR, setting atmospheric carbon dioxide concentrations at current, double, and quadruple levels for comparative analysis.
The results showed that as carbon dioxide concentrations increased, turbulence and current flows in the coastal waters of the Arctic and Antarctic intensified, and horizontal disturbances in seawater became markedly more pronounced.
To quantify this, the researchers used the "Finite-Size Lyapunov Exponent (FSLE)," an index that measures how quickly two water particles separate. A higher value indicates more active mixing and stronger disturbances.
Simulation results predicted that the rapid decline of sea ice due to warming would strengthen currents and turbulence in polar waters, transforming future polar oceans into even more "dynamic seas."
In particular, the causes of intensified disturbances in the Arctic and Antarctic were found to be different.
In the Arctic Ocean, reduced sea ice increased wind friction, strengthening surface circulation and turbulence. In the Antarctic, the inflow of meltwater from sea ice increased seawater density differences, intensifying ocean currents.
First author Lee Gyuseok explained, "Geographical structural differences between the Arctic Ocean and Antarctic coasts lead to different disturbance patterns. Nevertheless, if warming continues, horizontal disturbances will be greatly intensified in both regions."
Corresponding author Lee Joon, a professor at the Climate Science Research Institute at Pusan National University, stated, "The increase in ocean disturbances can have a significant impact on the entire polar ecosystem, including the survival of fish eggs and larvae, and nutrient cycling."
Axel Timmermann, Team Leader, said, "We are developing a next-generation Earth system model that integrates the interactions between climate and life. Through this, we will be able to gain a deeper understanding of how polar ecosystems respond to warming."
Axel Timmermann, Team Leader.
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