It's Not Just Wind That Changes Arctic Ocean Currents... Korea Polar Research Institute Identifies Causes of Current Variations [Reading Science]

East Siberian Sea Currents Driven by Summer Freshwater Influx
Key to Predicting Arctic Environmental Changes Identified
Link Between Pacific Seawater Inflow and Pressure Differences Confirmed
"Potential for Predictions Three Months in Advance"

A study has found that the influx of freshwater during the summer is the primary factor determining the flow of currents in the East Siberian Sea, a key area influencing environmental changes in the Arctic Ocean. This confirms that not only wind, which has long been considered the main cause of current fluctuations, but also changes in salinity due to river inflow, play a significant role.

The Korea Polar Research Institute announced on June 4 that its Arctic research team has identified the mechanisms behind current variations by comprehensively analyzing observational data from the East Siberian Sea continental shelf, satellite data, and long-term ocean reanalysis data.

Seasonal Variation of the East Siberian Sea Currents According to Salinity Changes. A schematic diagram of the currents in the Arctic East Siberian Sea and the adjacent Pacific waters (above), and graphs comparing sea surface height, salinity, and currents along the coastal cross-section (A-A’) of the East Siberian Sea (below). Provided by the research team

The East Siberian Sea serves as a crucial passageway where Pacific seawater and freshwater from Siberian rivers meet and spread throughout the Arctic Ocean. Changes in currents, water temperature, and salinity in this region directly impact sea ice distribution, the ecosystem, and the overall circulation structure of the Arctic Ocean, making it an important area for understanding environmental changes in the Arctic.

Freshwater, Not Wind, Changed the Direction of Currents

After analyzing observational data collected from 2021 to 2023, the research team discovered that during the summer months (July to September), currents near the coast and those offshore in the East Siberian Sea flow in opposite directions.

While the coastal currents flowed westward under the influence of wind, the offshore currents beyond the continental shelf intensified in an eastward direction. The researchers explained that this difference was due to the large-scale inflow of freshwater from Siberian rivers.

When freshwater flows in, the surface salinity decreases, causing the coastal sea surface to rise relatively higher, and the resulting slope between the coastal and offshore sea surface drives the currents eastward. Through this, the team confirmed that, in addition to wind, changes in salinity due to freshwater inflow are a key factor controlling the currents.

The Araon ship's simultaneous field observation activities in the East Siberian Sea. Provided by the Korea Polar Research Institute

The team also found that the pressure difference between Siberia and Alaska is related to changes in the amount of Pacific seawater entering the Arctic Ocean. Notably, this pressure pattern appears about three months before the actual influx of Pacific water, suggesting its potential use in predicting future environmental changes in the Arctic Ocean.

Park Taeuk, principal researcher at the Korea Polar Research Institute, stated, "This study identifies the core principles behind current variations in the Arctic Ocean, which is most sensitive to climate change. Since ocean currents are the fundamental flow affecting the movement of heat and freshwater, sea ice distribution, and nutrient cycling, these findings will serve as essential data for understanding and predicting future environmental changes in the Arctic Ocean."

Shin Hyungchul, director of the Korea Polar Research Institute, remarked, "Research that scientifically uncovers the interactions between land, sea, and atmosphere will provide a vital foundation for responding to future climate crises and changes in the Arctic ecosystem."

This research was supported by the Ministry of Oceans and Fisheries' "Arctic Ocean Warming-Marine Ecosystem Change Monitoring and Future Outlook Study" project, and the results were published in April in the international journal 'npj Climate and Atmospheric Science,' a Nature Partner Journal.

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