Mobile version

Eddy-steered current

Image of the month - April 2004

Sea surface temperature contour levels superimposed on bathymetry, and the "twisting force" exerted by eddies (from altimetry): in blue, eddies permit the current to flow to the south.  (Credits Proudman Oceanographic Laboratory (POL) )

 

Why study eddies? One can think that such rather small features have little impact on the global ocean. But, in fact, eddies impact on current speed, and they can steer them.

We saw (Image of the Month, July 2003) that currents can be steered by gaps in the ocean ridges, like at the Eltanin fracture zone (at about 230°E, 58°S in the Southern Ocean). The strong "jets" (i.e. narrow, fast currents) thus created have something strange: if they were only steered by the Earth rotation, they shouldn't go south. But they do. That normally require twisting force to allow the water to move over the earth's curvature. The answer is that eddies exert a twisting force by carrying vorticity from the jet's centre.

Global bathymetry from altimetry data
(Credits UCSD/Scripps Institution of Oceanography)

See also:

Websites on this subject:

References

  • Hughes, C.W., and E. R. Ash, 2001: Eddy Forcing of the mean flow in the Southern Ocean. J. Geophys. Res., 106(C2), 2713-2722.
EnglishFrançaisEspañol
Rss feedsContactSitemapPartnersFAQGlossaryLexiconMobile
You must enable cookies in your browser preferences to save the modifications
You are using an older version of Internet Explorer, please update to take full advantage of Aviso+ features

Customize the home page

View all widgets
Reduce display
Public profile
User profile

Select/Deselect widgets

Discover AVISO+

Customizable home, reading tools, products search guide, etc.. Discover step by step the features of the new site AVISO+.

Customizable homepage

The new home page is composed of blocks called "widgets".

Rearrange the blocks with a "Click & Drop".

Hide a widget with the cross at the top right. Reset or add a widget with the "wrench" icon. The "User" and "Public" profiles offer a predefined organization.

All the modifications are automatically saved as cookies on your machine so as to enable you to have your own specific AVISO+.

Reading tools

Ease your reading by choosing the page background colour (black/white) and/or by modifying the font size.

Browsing menu and breadcrum trail

To ease your browsing through AVISO+, you can use at any time the main banner items with the interactive submenus or use the browsing menu on the left side of the screen (it is open by default). For more readiness of the page contents, you can fold and unfold the browsing menu by clicking on the tab. At any time you can know where you are thanks to the browsing menu or the breadcrum at the top of the page.

Products search guide

The first submenu of the "Data" banner item leads you to a new search form enabling you to find quickier the product that suits your needs. The list of results is updated according to your selection criteria.

AVISO+ Multimedia

The first submenu of the "Multimedia" banner item leads you to AVISO+ collections of images and videos linked to altimetry and its applications. Have a nice visit!