The Role of Eddies
It is important to keep in mind that the large-scale sinking and rising of water involved in meridional overturning circulation is a very complex, three-dimensional phenomenon. The movement of water does not follow a single simple path along the surface or deep below and is not driven by winds or density differences alone. With recent advances in ocean observation and measurement techniques, oceanographers have found that the overturning circulation results from a complex interaction among many variables—including winds, tides, density, temperature, topography of the ocean floor, and the effects of eddies—at different time and space scales.
Eddies can travel for long distances over weeks or months before their energy decreases. As they move along, changing as they go, these swirling currents transport heat, salt, and nutrients. Eddies extend to great depths and have a large effect on the spreading of deep waters. For example, researchers have discovered that there are multiple pathways for dense, deep waters in the North Atlantic to travel southward, with eddies driving some of the flow toward the interior of the ocean basin.
This visualization shows surface currents over a one-year period. Play the video once through to see evidence of eddies. Then watch it again, pausing at various points in the video to compare the dynamic flow of eddies at different times.
| Keyboard Shortcut | Action |
|---|---|
| Space | Pause/Play video playback |
| Enter | Pause/Play video playback |
| m | Mute/Unmute video volume |
| Up and Down arrows | Increase and decrease volume by 10% |
| Right and Left arrows | Seek forward or backward by 5 seconds |
| 0-9 | Fast seek to x% of the video. |
| f | Enter or exit fullscreen. (Note: To exit fullscreen in flash press the Esc key. |
| c | Press c to toggle captions on or off |
Take Notes
How do eddy patterns change throughout the year shown in the video? What evidence does the video provide about the role eddies play in transporting heat?
Produced by
