Understanding oceanic currents has been an important part of scientific research for the past decade. Already in 2012, NASA’s “Perpetual Ocean” — a realistic visualization of large eddy currents published by the Goddard Space Flight Center — had attracted a fair amount of public attention due to its resemblance to Vincent van Gogh’s oil painting, The Starry Night.

Up to now, most research on ocean currents had been performed on mesoscale waves, which focused on waves of the sizes of hundreds of kilometers. However, the recent research results of Professor Sung Yong Kim and his research group from the Department of Mechanical Engineering succeeded in understanding sub-mesoscale currents, characterizing the properties of waves roughly the size of a kilometer. This research was performed using two high frequency radar systems to collect spatial and temporal data of currents of the sizes of one to ten kilometers occurring in the eastern coast of Korea. Using big data analysis, Professor Kim’s work was able to demonstrate the relationship between the kinetic energy spectrum and the wavenumber of summer currents, where sub-mesoscale currents are known to display more regular variations. Currents during the winter display more irregularity and remain more difficult to characterize.

The few researches that did focus on sub-mesoscale currents were only limited to computer simulations. Professor Kim’s research, however, did not rely just on numerical techniques to simulate the rapidly changing small scale currents. Using radars installed at Imwon Port, Korea and geostationary satellites, the research team was able to obtain data on surface currents and understand the governing hydrodynamics.

The results of this research are expected to guide the parameterization of waves necessary in marine physics and ocean climate studies. Possible applications include modeling fuel leaks in the ocean or tracking waste.

Sub-mesoscale currents not only give insight into the currents themselves, but also are important to the understanding of ecological processes such as the formation of red tides and the growth of marine life. It is also projected to add accuracy to weather forecasts through a better understanding of the behavior of the surrounding bulks of water.

Professor Kim’s research has been published in the Journal of Geophysical Research-Oceans, with two MS students of the group, Jang Gon Yoo and Eunae Lee, co-authoring as first authors. His research has been funded by the National Research Foundation of Korea, Korea Institute of Ocean Science and Technology, and the Korean Coast Guard Research Center.