Climate change is making one of the world’s strongest currents flow faster – Growth for that?
A shift in the Southern Ocean, the region that absorbs the most of anthropogenic warming globally, detected with new technology
UNIVERSITY OF CALIFORNIA – SAN DIEGO
CREDIT: ISA ROSSO / SOCCOM
The Antarctic Current (ACC), the only ocean current orbiting the planet, is accelerating. For the first time, scientists can tell that this is happening by taking advantage of a decades-long set of observational records.
Researchers from the Scripps Institute of Oceanography at UC San Diego, the Woods Hole Oceanographic Institute, the Chinese Academy of Sciences, and UC Riverside used satellite measurements of sea surface elevation and collected data. Collected by a global network of ocean buoys called Argo to detect the Southern Ocean’s Upper Layer Velocity trends that have been hidden by scientists until now.
The team representing the Southern Ocean Climatology and Modeling and Observation (SOCCOM) project, funded by the National Science Foundation, reports its findings in the November 29 issue of the journal Nature. Natural climate change.
The passing westerly winds have accelerated as the climate warms. Models show that wind speed does not change ocean currents much. Instead, it powers oceanic eddies, which are circular movements of water that flows against the main currents.
Jia-Rui Shi, formerly a PhD student at Scripps Oceanography and now a postdoctoral researcher at the Woods Hole Institute of Oceanography, said: “From both observations and models, we see that variability The heat of the ocean is causing the significant ocean current acceleration detected in recent decades. .
“This acceleration of the ACC, especially as its jet is focused on the Near Pole Front, facilitates the exchange of assets, such as heat or carbon, between ocean basins. and gives the opportunity for these properties to increase in subsurface subtropical regions.”
The ACC surrounds Antarctica and separates the cold waters to the south from the warmer subtropical waters to its north. This warmer part of the Southern Ocean would absorb a lot of the heat that human activities are adding to Earth’s atmosphere. For this reason, scientists consider it important to understand its dynamics, as what happens there can affect climate everywhere else.
The ocean’s warming pattern is important. As the slope, or amount of heat difference, between warm and cold water increases, the electric current between those two masses accelerates.
Co-author Lynne Talley, an oceanographer at Scripps Oceanography, said: “The ACC is mainly driven by the wind, but we show that changes in its speed are mainly due to changes in the wind. thermal gradients”.
Long-term data on changes in the Southern Ocean were difficult to obtain prior to the arrival of satellite-mounted instruments and the Argo network. That network of self-propelled buoys, which measure ocean conditions such as temperature and salinity, began operation in 1999 and reached full capacity in 2007. All 4,000 buoys float across the world’s oceans. The world continues to collect data to this day. As a result, the researchers were able to use more than a decade’s worth of comprehensive Argo data to distinguish the trend of accelerated currents from natural variability.
It is likely that the flow rate will increase even more as the Southern Ocean continues to experience heat from anthropogenic global warming, the study co-authors say.
In addition to Shi and Talley, the team includes climate scientists Oceanography Scripps Shang-Ping Xie, Qihua Peng of the Chinese Academy of Sciences, and Wei Liu of UC Riverside.
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JOURNEYS
Natural climate change
DOI
RESEARCH METHODS
Data analysis / statistics
RESEARCH SUBJECTS
Do not apply
ARTICLE TITLE
Ocean warming and Southern Ocean regional flow acceleration
ARTICLE PUBLICATION DATE
November 29, 2021
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