Ocean gyre

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The five major ocean gyres


Major gyres[edit]

The following are the five most notable gyres:[2]

Other gyres[edit]

Tropical gyres[edit]

All of the world's larger gyres


Subtropical gyres[edit]


The intensified western boundary current of the North Atlantic Gyre is the Gulf Stream, in the North Pacific it's the Kuroshio Current, in the South Atlantic it's the Brazil Current, in the South Pacific it's the East Australian Current, and in the Indian Ocean it's the Agulhas Current.

Subpolar gyres[edit]

Subpolar gyres form at high latitudes (around 60°). Circulation of surface wind and ocean water is counterclockwise in the Northern Hemisphere, around a low-pressure area, such as the persistent Aleutian Low and the Icelandic Low. Surface currents generally move outward from the center of the system. This drives the Ekman transport, which creates an upwelling of nutrient-rich water from the lower depths.[4]


Climate change[edit]

Recently stronger winds, especially the subtropical trade winds in the Pacific ocean have provided a mechanism for vertical heat distribution. The effect are changes in the ocean currents, increasing the subtropical overturning, which are also related to the El Niño and La Niña phenomenon. Depending on stochastic natural variability fluctuations, during La Niña years around 30% more heat from the upper ocean layer is transported into the deeper ocean.[5] Several studies in recent years, found a multidecadal increase in OHC of the deep and upper ocean regions and attribute the heat uptake to anthropogenic warming.[6]

Influence of Coriolis effect and Ekman transport[edit]

The influence of the Coriolis effect on westward intensification. Without the Coriolis effect, water currents would form a regular and symmetrical gyre. However, because the Coriolis effect is strongest near the poles, water flowing eastward at high latitudes (red arrows) turns sooner to the right (clockwise), "short circuiting" the gyre. And because the Coriolis effect is nonexistent at the equator, water flowing westward near the equator (green arrows) tends not to turn clockwise until it encounters a blocking continent. Westward boundary currents are therefore faster and deeper than eastern boundary currents, and the geostrophic hill is offset to the west.

See also[edit]


  1. ^ Heinemann, B. and the Open University (1998) Ocean circulation, Oxford University Press: Page 98
  2. ^ a b The five most notable gyres PowerPoint Presentation
  3. ^ Indian Monsoon Gyres
  4. ^ Wind Driven Surface Currents: Gyres
  5. ^ Balmaseda, Trenberth & Källén (2013). [[1] Essay Distinctive climate signals in reanalysis of global ocean heat content]. doi:10.1002/grl.50382. 
  6. ^ Abraham et al. (2013). A review of global ocean temperature observations: Implications for ocean heat content estimates and climate change. doi:10.1002/rog.20022. 

External links[edit]