Researchers release a float into the ocean. Isais Rosso/SOCCOM
The only ocean current that is around the planet is speeding up. Scientists have been able to tell this is happening for the first time by taking advantage of a decades-long set of observational records.
Satellite data and data collected by the global network of ocean floats called "Argo" were used by researchers from the University of California San Diego, the Woods Hole Oceanographic Institution, and the Chinese Academy of Sciences to detect a trend in Southern Ocean upper layer velocity.
The findings of the National Science Foundation-funded Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project are reported in the November issue of the journal Nature Climate Change.
As the climate warms, westerly winds have sped up. The models show that the ocean currents are not changed by the wind speedup. The ocean eddies are circular movements of water running counter to the main canals.
"From both observations and models, we find that the ocean heat change is causing the significant ocean current acceleration detected during recent decades," said Jia-Rui Shi, a researcher at Woods Hole Oceanographic Institution.
The opportunity for these properties to increase in sub-tropical regions is created by the speedup of the ACC, especially its jet centered on the Subantarctic Front.
The cold water in the south is separated from the warmer water in the north by the ACC. The Southern Ocean takes up a lot of the heat that humans add to Earth's atmosphere. Scientists consider it vital to understand its dynamics since it could affect climate everywhere else.
The ocean warming pattern is important. Currents between the two mass speed up when the heat difference between the warm and cold waters increases.
The heat gradient is the main cause of the changes in the speed of the ACC.
Satellite-mounted instruments and the Argo network made it possible for long-term data to be captured in the Southern Ocean. The network of floats that measure ocean conditions began in 1999 and reached full capacity in 2007. 4,000 floats across the world's oceans continue to collect data. The researchers were able to use more than a decade's worth of comprehensive Argo data to distinguish the trend of the current from natural variability.
The Southern Ocean is taking up heat from global warming and it is likely that the current speed will increase even more.
The research team included a climate scientist from the Scripps Oceanography and a Chinese Academy of Sciences scientist.
Nature Climate Change is more information about Ocean warming and Southern Ocean flow. www.nature.com/articles/s41558-021-01212-5
Nature Climate Change Journal information.
Climate change is making one of the world's strongest currents flow faster.
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