All Topics  
Gyre

 

 
   Email Print
   Bookmark   Link
 

 

Gyre
 
 
  Topics Gyre Topic Home

A gyre is any manner of swirling vortex
Vortex

A vortex is a Rotation, often Turbulence,flow of fluid. Any spiral motion with closed Streamlines, streaklines and pathlines is vortex flow....
, particularly large-scale wind
WIND

The Global Geospace Science WIND satellite is a NASA science spacecraft launched at 04:31:00 EST on November 1, 1994 from launch pad 17B at Cape Canaveral Air Force Station in Merritt_Island%2C_Florida, Florida aboard a McDonnell Douglas Delta II 7925-10 rocket....
 and ocean currents. Gyres are caused by the Coriolis effect
Coriolis effect

In physics, the Coriolis effect is an apparent deflection of moving objects when they are viewed from a rotating reference frame.Newton's laws of motion govern the motion of an object in an inertial frame of reference....
; planetary vorticity
Vorticity

Vorticity is a mathematical concept used in fluid dynamics. It can be related to the amount of "Circulation " or "rotation" in a fluid.The average vorticity in a small region of fluid flow is equal to the Circulation around the boundary of the small region, divided by the area A of the small region....
 along with horizontal and vertical friction which determine the circulation patterns from the wind curl (torque
Torque

Torque is the tendency of a force to rotate an object about an axis . Just as a force is a push or a pull, a torque can be thought of as a twist....
).

Ocean gyres
The Earth's oceans have the following major gyres:



This gyre comprises most of the northern Pacific Ocean
Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Mare Pacificum, "peaceful sea", bestowed upon it by the Portugal explorer Ferdinand Magellan....
. It is located between the equator
Equator

The equator is the intersection of the Earth's surface with the Plane perpendicular to the Earth's rotation and containing the Earth's center of mass....
 and 50º N
50th parallel north

The 50th parallel north is a circle of latitude that is 50 degree true north of the Earth equator.Starting at the Prime Meridian and heading eastwards, the parallel 50? north passes through:...
 latitude
Latitude

Latitude, usually denoted symbolically by the Greek letter phi gives the location of a place on Earth north or south of the equator. Lines of Latitude are the horizontal lines shown running east-to-west on maps ....
 and occupies an area of approximately ten million square miles (34 million km²).






Discussion
Ask a question about 'Gyre'
Start a new discussion about 'Gyre'
Answer questions from other users
Full Discussion Forum



Encyclopedia


A gyre is any manner of swirling vortex
Vortex

A vortex is a Rotation, often Turbulence,flow of fluid. Any spiral motion with closed Streamlines, streaklines and pathlines is vortex flow....
, particularly large-scale wind
WIND

The Global Geospace Science WIND satellite is a NASA science spacecraft launched at 04:31:00 EST on November 1, 1994 from launch pad 17B at Cape Canaveral Air Force Station in Merritt_Island%2C_Florida, Florida aboard a McDonnell Douglas Delta II 7925-10 rocket....
 and ocean currents. Gyres are caused by the Coriolis effect
Coriolis effect

In physics, the Coriolis effect is an apparent deflection of moving objects when they are viewed from a rotating reference frame.Newton's laws of motion govern the motion of an object in an inertial frame of reference....
; planetary vorticity
Vorticity

Vorticity is a mathematical concept used in fluid dynamics. It can be related to the amount of "Circulation " or "rotation" in a fluid.The average vorticity in a small region of fluid flow is equal to the Circulation around the boundary of the small region, divided by the area A of the small region....
 along with horizontal and vertical friction which determine the circulation patterns from the wind curl (torque
Torque

Torque is the tendency of a force to rotate an object about an axis . Just as a force is a push or a pull, a torque can be thought of as a twist....
).

Ocean gyres


The Earth's oceans have the following major gyres:

  • North Atlantic Subpolar Gyre
  • North Pacific Subpolar Gyre
    • Contains the smaller Alaska Gyre
  • North Atlantic Subtropical Gyre
    • Gulf Stream
      Gulf Stream

      The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Current, is a powerful, warm, and swift Atlantic Ocean ocean current that originates in the Gulf of Mexico, exits through the Straits of Florida, and follows the eastern coastlines of the United States and Newfoundland and Labrador before crossing the At...
      , Labrador Current
      Labrador Current

      The Labrador Current is a cold current in the north Atlantic Ocean which flows from the Arctic Ocean south along the coast of Labrador and passes around Newfoundland , continuing south along the east coast of Nova Scotia....
      , East Greenland Current
      East Greenland Current

      The East Greenland Current originates in the Arctic Ocean and brings cold, low salinity, southbound water along the eastern coast of Greenland....
      , North Atlantic Current
      North Atlantic Current

      The North Atlantic Current is a powerful warm ocean current that continues the Gulf Stream northeast. West of Ireland it splits in two. One branch goes south while the other continues north along the coast of northwestern Europe where it has a considerable warming influence on the climate....
      , North Atlantic Equatorial Current. Contains the Sargasso Sea
      Sargasso Sea

      The Sargasso Sea is an elongated region in the middle of the North Atlantic Ocean, surrounded by ocean currents. It is bounded on the west by the Gulf Stream; on the north, by the North Atlantic Current; on the east, by the Canary Current; and on the south, by the North Equatorial Current....
      .
  • North Pacific Subtropical Gyre also known as North Pacific Gyre


This gyre comprises most of the northern Pacific Ocean
Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. Its name is derived from the Latin name Mare Pacificum, "peaceful sea", bestowed upon it by the Portugal explorer Ferdinand Magellan....
. It is located between the equator
Equator

The equator is the intersection of the Earth's surface with the Plane perpendicular to the Earth's rotation and containing the Earth's center of mass....
 and 50º N
50th parallel north

The 50th parallel north is a circle of latitude that is 50 degree true north of the Earth equator.Starting at the Prime Meridian and heading eastwards, the parallel 50? north passes through:...
 latitude
Latitude

Latitude, usually denoted symbolically by the Greek letter phi gives the location of a place on Earth north or south of the equator. Lines of Latitude are the horizontal lines shown running east-to-west on maps ....
 and occupies an area of approximately ten million square miles (34 million km²). The North Pacific Gyre
Gyre

A gyre is any manner of swirling vortex, particularly large-scale wind and ocean currents. Gyres are caused by the Coriolis effect; planetary vorticity along with horizontal and vertical friction which determine the circulation patterns from the wind curl ....
 has a clockwise circular pattern and comprises four prevailing ocean currents: the North Pacific Current
North Pacific Current

The North Pacific Current is a slow warm water current that flows west-to-east between 40th parallel north and 50th parallel north in the Pacific Ocean....
 to the north, the California Current
California Current

The California Current is a Pacific Ocean ocean current that moves south along the western coast of North America, beginning off southern British Columbia, and ending off southern Baja California....
 to the east, the North Equatorial Current
North Equatorial Current

The North Equatorial Current is a significant Pacific Ocean and Atlantic Ocean current that flows east-to-west between about 10th parallel north and 20th parallel north....
 to the south, and the Kuroshio Current
Kuroshio Current

The Kuroshio is a strong western boundary current in the western north Pacific Ocean. It begins off the east coast of Taiwan and flows northeastward past Japan, where it merges with the easterly drift of the North Pacific Current....
 to the west. An accumulation of man-made marine debris
Marine debris

Marine debris, also known as marine litter, is human-created waste that has deliberately or accidentally become afloat in a lake, sea, ocean or waterway....
 known as the "Great Pacific Garbage Patch
Great Pacific Garbage Patch

The Great Pacific Garbage Patch, also described as the Eastern Garbage Patch or the Pacific Trash Vortex, is a gyre of marine debris in the central North Pacific Ocean located roughly between 135th meridian west to 155th meridian west and 35th parallel north to 42nd parallel north....
" is collecting in the gyre.


  • South Atlantic Subtropical Gyre
    • Contains the smaller Brazil Current System
  • South Pacific Subtropical Gyre
    • Contains the smaller East Australian Current System
  • Indian Ocean Subtropical Gyre (Southern Hemisphere)
    • Contains the smaller Agulhas Current System
  • Antarctic Circumpolar Current
    Antarctic Circumpolar Current

    The Antarctic Circumpolar Current is an ocean current that flows from west to east around Antarctica. An alternate name for the ACC is the West Wind Drift....
  • Weddell Sea Subpolar Gyre
    Weddell Gyre

    Two clockwise Antarctic gyres swirl within the southern ocean. They are known as the Weddell and Ross Gyres, as they reside in the Weddell Sea and the Ross Sea, respectively....
     (Southern Ocean
    Southern Ocean

    The Southern Ocean, also known as the Great Southern Ocean, the Antarctic Ocean and the South Polar Ocean, comprises the southernmost waters of the World Ocean south of 60th parallel south latitude....
    )
  • Ross Sea Subpolar Gyre


Tropical circulations are less unified and tend to be mostly east-west with minor north-south extent.
  • Atlantic Equatorial Current System (two counter-rotating circulations)
  • Pacific Equatorial/Tropical Current System
  • Indian Monsoon Gyres (Northern Indian Ocean, two counter-rotating circulations)


Subtropical gyres


The center of a subtropical gyre is a high pressure zone. Circulation around the high pressure is clockwise in the northern hemisphere and counterclockwise in the southern hemisphere, due to the Coriolis force. The high pressure in the center is due to the westerly winds on the northern side of the gyre and easterly trade winds on the southern side of the gyre. These cause frictional surface currents towards the latitude at the center of the gyre. The buildup of water in the center of the gyre creates equatorward flow in the upper 1000 to 2000 meters of the ocean, through rather complex dynamics. This equatorward flow is returned poleward in an intensified western boundary current (Western intensification).

The intensified western boundary current of the North Atlantic's subtropical gyre is the Gulf Stream
Gulf Stream

The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Current, is a powerful, warm, and swift Atlantic Ocean ocean current that originates in the Gulf of Mexico, exits through the Straits of Florida, and follows the eastern coastlines of the United States and Newfoundland and Labrador before crossing the At...
; in the North Pacific it is the Kuroshio; in the South Atlantic, it is the Brazil Current
Brazil Current

The Brazil Current is a warm water current that flows south along the Brazil south coast to the mouth of the R?o de la Plata. This current is caused by diversion of a portion of the Atlantic South Equatorial Current from where that current meets the South American continent....
; in the South Pacific, it is the East Australia Current; in the Indian Ocean, it is the Agulhas Current
Agulhas Current

The Agulhas Current is the Western Boundary Current of the South-West Indian Ocean and is part of the westward flowing South Equatorial Current....
.

Subpolar gyres


Subpolar gyres form at high latitudes (around 60 degrees). Circulation of surface wind and ocean water is counterclockwise in the Northern Hemisphere, around a low pressure system (such as the persistent Aleution Low and the Icelandic Low). Surface currents generally move outward from the center of the system. This drives Ekman transport
Ekman transport

Ekman transport, named for Vagn Walfrid Ekman, is the natural process by which wind causes movement of water near the ocean surface. Each layer of water in the ocean drags with it the layer beneath....
 which creates an upwelling
Upwelling

An Upwelling is an physical oceanography phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water....
 of nutrient-rich water from the lower depths.

Subpolar circulation in the southern hemisphere is dominated by the Antarctic Circumpolar Current
Antarctic Circumpolar Current

The Antarctic Circumpolar Current is an ocean current that flows from west to east around Antarctica. An alternate name for the ACC is the West Wind Drift....
 due to the lack of large landmasses breaking up the Southern Ocean
Southern Ocean

The Southern Ocean, also known as the Great Southern Ocean, the Antarctic Ocean and the South Polar Ocean, comprises the southernmost waters of the World Ocean south of 60th parallel south latitude....
. There are minor gyres in the Weddell and Ross Seas, which circulate in a clockwise direction.

See also

  • Anticyclone
    Anticyclone

    In meteorology, an anticyclone is a weather meteorological phenomenon in which there is a descending movement of the air and a high pressure area over the part of the planet's surface affected by it....
  • Cyclone
    Cyclone

    In meteorology, a cyclone refers to an area of closed, circular fluid motion rotating in the same direction as the Earth's rotation. This is usually characterized by inward spiraling winds that rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth....
  • Eddy (fluid dynamics)
    Eddy (fluid dynamics)

    In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid flows past an obstacle. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object....
  • Fluid dynamics
    Fluid dynamics

    In physics, fluid dynamics is the sub-discipline of fluid mechanics dealing with fluid flow — the natural science of fluids in motion....
  • Maelstrom
    Maelstrom

    A maelstrom is a very powerful whirlpool; a large, swirling body of water. A free vortex, it has considerable downdraft. The Nordic word was introduced into English by Edgar Allan Poe in his story "A Descent into the Maelstr?m" ....
  • Sargasso Sea
    Sargasso Sea

    The Sargasso Sea is an elongated region in the middle of the North Atlantic Ocean, surrounded by ocean currents. It is bounded on the west by the Gulf Stream; on the north, by the North Atlantic Current; on the east, by the Canary Current; and on the south, by the North Equatorial Current....
  • Skookumchuck
    Skookumchuck

    Skookumchuck is a word in the Chinook Jargon that is in common use in British Columbia English and occurs in Pacific Northwest English. Skookum means "strong" or "powerful", and "chuck" means water, so skookumchuck means "rapids" or "whitewater" ....
  • Vortex
    Vortex

    A vortex is a Rotation, often Turbulence,flow of fluid. Any spiral motion with closed Streamlines, streaklines and pathlines is vortex flow....
  • Whirlpool
    Whirlpool

    A whirlpool is a swirling body of water usually produced by ocean tides. The vast majority of whirlpools are not very powerful. More powerful ones are more properly termed maelstroms....


External links

  • — Georgia Institute of Technology