Global warming is accelerating one of the most powerful ocean currents

Previously, collecting information over a long period of time about changes in theSouthern Ocean (or Antarctic Ocean) was complicated. However, the Argo network and the availability of various satellite instruments have changed the game. The Argo network is a set of autonomous floats which currently number 4,000. Their mission is to measure ocean conditions around the globe, like the temperature and salinity.

Credit: tameteo.com

Researchers from the UC San Diego Scripps Institution of Oceanography then used the data collected by these technologies. They used this information to study the southern ocean. During the work, these scientists collaborated with those of the Woods Hole Oceanographic Institution, the Chinese Academy of Sciences and UC Riverside.

This research is part of the SOCCOM project (Southern Ocean Carbon and Climate Observations and Modeling). The experts published the results of their research on November 29, 2021 in the review Nature Climate Change.

Antarctic circumpolar current accelerates

the Antarctic circumpolar current (ACC in English) is a current that runs through theSouthern Ocean surrounding the Antarctic continent. It is the only current which realizes the around the Earth. Based on observations from decades ago, the researchers found that the current in question has accelerated during the last decades.

Due to global warming, the prevailing westerly winds hurried. However, scientists have found that this phenomenon has little influence on ocean currents. On the other hand, it energizes oceanic eddies.

The main responsible for the increase in the speed of ocean currents would rather be the rising ocean heat. So said Jia-Rui Shi, a postdoctoral researcher at the Woods Hole Institute of Oceanography. The point is that the ACC separates the cold southern waters from warmer subtropical waters. This abnormal increase in temperature is essentially linked to human activities.

Soon a disruption of the planetary climate?

In addition, acceleration of ACC promotesexchange of properties as the heat and carbon between ocean basins. Therefore, the phenomena occurring in this region could affect the global climate. For this reason, scientists believe that it is essential to understand its dynamics.

When the gradient (heat difference) between hot and cold water increases, the currents between them gain speed. For this reason, a ocean warming modeling is important.

“ACC is mostly wind driven, but we show that the changes in its speed are surprisingly due to changes in the heat gradient. ”
Lynne Talley, co-author and physical oceanographer at Scripps Oceanograph

SOURCE: SciTechDaily

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