Study finds surprising change in Indian Ocean current.
Past research has theorized that warming ocean temperatures in western boundary current regions combined with stronger and expanding global winds predicted by climate models have strengthened those currents while shifting them poleward. But in a finding with potentially important climatic implications, a new study published in Nature has uncovered much different dynamics in one of the strongest currents in the world, the Indian Ocean's Agulhas Current off the east coast of South Africa.
By studying 22 years of sea surface height satellite data as well as 3 years of ocean measurements taken from an array of current meters, Lisa Beal and Shane Elipot of the University of Miami were able to estimate the long-term transport of the Agulhas. They found that since the early 1990s, the current has gotten wider, not stronger, because winds are causing an escalation of turbulence, which leads to increases in both eddying and meandering in the current. The study suggests similar dynamics are occurring in the Kuroshio and East Australian Currents.
Western boundary currents, which form on the western side of ocean basins, transport warm water from the tropics to the poles. They are currently "warming at three times the rate of the rest of the world ocean," says Beal, and the new research "suggests this may be related to a broadening of these current systems."
The finding could be useful in future climate research, notes Elipot, because "increased eddying and meandering could act to decrease poleward heat transport" and increase coastal upwelling. [Source: University of Miami Rosenstiel School of Marine and Atmospheric Science]
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|Title Annotation:||NOWCAST: NEWS AND NOTES|
|Publication:||Bulletin of the American Meteorological Society|
|Article Type:||Brief article|
|Date:||Mar 1, 2017|
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