The role of eddies in shaping the climate 

Seminar by Prof. Sukyung Lee from The Pennsylvania State University

24 November 2023
KST 10:30 – 11:30

The Seminar is being held in Room 1010 (Jasmin) – Integrated mechanical engineering building. Click here for the campus map.

Eddies are fundamental components of the general circulation which enable the above regional climate differences to be realized, regardless of the cause – anthropogenic climate change or natural/internal climate variability. In climate science, eddies are often regarded as some entity that only passively responds to north-south temperature changes. However, this is not the case. Instead, eddies can be excited independent of the north-south temperature gradient, changing the jet position and strength, and even precipitation distribution. In fact, eddy momentum flux plays a pivotal role in setting the latitudinal precipitation distribution. The extratropical precipitation distribution closely aligns with the eddy-driven transformed Eulerian mean (TEM) vertical motion. When the poleward eddy momentum flux is sufficiently strong, the secondary precipitation peak shifts from 40oN to 60oN. This finding indicates that future changes in the eddy momentum flux could play a fundamental role in determining the future precipitation distribution. 

In the ocean, eddies also play a fundamental role in determining how the ocean responds to climate change. Climate models that explicitly simulate eddies can also simulate exchanges of heat and carbon between the atmosphere and ocean that are much closer to nature than those that do not. Theoretical interpretations of this difference also exist. 

Eddies in the atmosphere and ocean operate under the same physical principle. As such, it is important to better understand the fundamental mechanisms of eddies, not only for understanding what sets the mean state of the atmosphere and ocean, but also for gaining more accurate predictions of how climate will change in the future.