More settled science: these whirlpools transport vast amount of water and heat vertically in the ocean, somewhat like hurricanes do for the atmosphere. It is fun to imagine “Trenberth’s missing heat” being sucked down one of these.
Via Yahoo News:
Satellites have shown two mysterious ‘black hole’ whirlpools in the South Atlantic ocean – ultra powerful “vortexes” which suck water down into the depths.
Two of the black holes – or “maelstroms” – have been sighted in three months by physicists from Zurich and Miami who have written a new paper using satellite altimetry to look for and identify these oceanic vortices. They write in their paper:
The South Atlantic ocean region in question is bounded by longitudes [14W, 9E] and latitudes [39S, 21S]. Using satellite altimetry data, we seek coherent Lagrangian vortices (black-hole eddies, for short) over a 90-day time period, ranging from 24 November 2006 to 22 February 2007.
The powerful vortices of current have been described as ‘maelstroms’ and are ‘mathematical analogues’ for black holes – which is to say they do exactly the same with water that black holes do with light. The discovery could give new insights into how oceanic currents transport debris and may even have implications for climate change studies.
The maelstroms are detected by their rotating edges, which the scientists found were reliable indicators of the vortex within, based on pioneering research carried out by Stephen Hawking on black holes:
‘Intuitively, one expects that any…vortex in the fluid must contain such a singularity in its interior, just as all black holes are expected to contain Penrose-Hawking singularities. This expectation turns out to be correct’.
The singularities, as they have been termed, last for months at a time, moving across the ocean without interference from other currents. Thus they can transport water of different temperatures and salinity to other areas of the ocean, potentially influencing the regional climate.
Haller and Beron-Vera found that the vortices transported water in a north-western direction 30% faster than had previously been reckoned – at a rate equating to 1.3 million cubic meters of water per second.
In addition, the maelstroms were found to occur four times deeper in the ocean than previously estimated; the study found examples as deep as 2000 meters below the surface.
Here is the draft paper, final publication in the Journal of Fluid Mechanics.
Coherent Lagrangian vortices: The black holes of turbulence
G. Hallery and F. J. Beron-Vera (Received 13 May 2013; revised 18 July 2013; accepted 23 July 2013.)
We introduce a simple variational principle for coherent material vortices in two-dimensional turbulence. Vortex boundaries are sought as closed stationary curves of the averaged Lagrangian strain. Solutions to this problem turn out to be mathematically equivalent to photon spheres around black holes in cosmology. The uidic photon spheres satisfy explicit dierential equations whose outermost limit cycles are optimal Lagrangian vortex boundaries. As an application, we uncover super-coherent material eddies in the SouthAtlantic, which yield specic Lagrangian transport estimates for Agulhas rings.
In this NASA visualization video (not part of the paper, but related) one can see quasi-permanent eddies throughout the south Atlantic.
Data sources: sea surface height from NASA’s Topex/Poseidon, Jason-1, and Ocean Surface Topography Mission/Jason-2 satellite altimeters; gravity from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment mission; surface wind stress from NASA’s QuikScat mission; sea surface temperature from the NASA/Japan Aerospace Exploration Agency Advanced Microwave Scanning Radiometer-EOS; sea ice concentration and velocity from passive microwave radiometers; temperature and salinity profiles from shipborne casts, moorings and the international Argo ocean observation system.
- Black Hole Analogue Discovered in South Atlantic Ocean (technologyreview.com)