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By: Jason LaFlore Jacquelyn Matia Matt Middendorf John Onsa

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1 By: Jason LaFlore Jacquelyn Matia Matt Middendorf John Onsa
Ocean Circulation Patterns By: Jason LaFlore Jacquelyn Matia Matt Middendorf John Onsa

2 Ocean Circulation is the large scale movement of waters in the ocean basins.
Winds drive surface circulation, and the cooling and sinking of waters in the polar regions drive deep circulation JM

3 Ocean currents are constantly in motion as shown below:
Ocean currents move in many different patterns affected by: wind, salinity in the water, heat, the earths rotation, etc. JM

4 Ocean Circulation Patterns effect:
The climate Living conditions for plants and animals in the ocean and on land JM

5 This map shows the major movements of water in oceans of the world.
JM

6 Two Primary Types of Ocean Circulation
Wind Driven Circulation – (which involves the surface) Thermohaline Circulation- (which involves density and depth) -caused by density differences - such as temperature and salinity JM

7 Ocean currents are affected by two types of forces:
Primary forces- which are forces that start the motion of the water Secondary forces- which influence the direction in which the currents flow JM

8 Some of these forces include:
Solar heating- causes the water to expand Winds- push the ocean water Gravity- tends to pull water (for example down a hill) Coriolis Force- which causes water to move to the right around gyres JM

9 The Corolis Effect The Corolis Effect is the deflection of objects, winds, and currents on the surface of the earth owing to the planet’s rotation. This plays a major role in the temperature and weather patterns of the earth M.M.

10 The Coriolis Effect cont.
As a result of the Coriolis Effect, north-flowing currents in the Northern hemisphere deflect to the east, while south-flowing currents deflect to the west. The opposite is true for the Southern Hemisphere. This plays a major role in ocean currents and circulation. M.M.

11 Demonstration of the Coriolis Effect
This shows how the prevailing surface winds flow. As you can see, it is rather interesting how the warmer westerly winds flow north and the trade winds from the northeast as well as the polar easterlies flow south. M.M.

12 The Ocean’s Conveyor Belt

13 The Oceanic Circulation Cycle
Near surface seawater begins its travel deep into the ocean in the North Atlantic. The downwelling of this water is caused by high levels of evaporation which cools and increases the salinity of the seawater located here. This seawater then moves south along the coast of North and South America until it reaches Antarctica At Antarctica, the cold and dense seawater then travels eastward. During this part of its voyage the flow splits off into two currents that move northward. In the North Pacific (off the coast of Asia) and in the Indian Ocean (off the coast of Africa), these two currents move from the ocean floor to its surface creating upwellings. The flow then becomes near surface moving back to the starting point in the North Atlantic. One complete circuit of this flow of seawater is estimated to take about 1,000 years M.M.

14 Conclusions The Coriolis Effect stems from the fact that at different latitudes on the earth, different points experience different rates of rotation. This causes certain objects to be “deflected” from their original path. As we can see, the Coriolis Effect has a large impact on the the patterns of ocean circulation This effects the weather and climate of the world by directing winds and warm or cold ocean currents to certain parts of the globe This process takes a long time however, often up to 1,000 years M.M.

15 Ocean Circulation Patterns
The Historical Foundations: Earliest knowledge of Ocean Currents came from various ship captains and explorers Matthew Fontaine Maury - Maury was the first person to use large amounts of ocean data in a study of surface currents. He also was responsible for publishing the first pilot charts and sailing directions for all the oceans of the world. J.O.

16 Ocean Circulation MAP Taken from the Website:

17 Ocean Circulation Patterns
Surface Circulation Thermohaline Circulation J.O.

18 One of two Circulation Patterns found in all Oceans across the world.
Surface Circulation One of two Circulation Patterns found in all Oceans across the world. Surface Circulation is the Horizontal movement of water that is driven by the force of winds at the surface. J.O.

19 Surface Circulation Cont
Surface Circulation is driven by winds. These winds are determined by the Earth’s radiation budget which determine net heat gain at low latitudes and net heat loss at high latitudes. Sets up hemispheric and atmospheric circulation cells which breaks up into three main cells pre hemisphere: the Hadley cell, Ferrell cell, and polar Cell. J.O.

20 Surface Circulation Map
J.O. Taken from the Website:

21 Thermohaline Circulation Pattern
Thermohaline Circulation is the second of Circulation patterns that effects the earth’s oceans. The pattern is made up of the vertical movement of water which is driven by the density differences from variations in water. These Variations include temperature and Salinity Three main processes make up the Thermohalne Circulation Pattern J.O.

22 Thermohaline Circulation Cont
Processes that Make up the Thermohaline Pattern: Tidal Forces, Wind Stress, and Density differences. -The density of the sea water is controlled by temperature (Thermo) and salinity (Haline), and the circulation which is driven by density differences J.O.

23 Thermohaline Circulation Pattern Map
J.O. Taken form the website:

24 La Nina Means the Little Girl Also known as El Viejo
Refers to cooler than normal sea-surface temperatures in the central and eastern tropical Pacific Ocean that impact global weather patterns Conditions recur every few years and can persist as long as 2 years JL

25 Causes Preceded by a buildup of cooler-than-normal subsurface waters in the Tropical Pacific Eastward-moving atmospheric and oceanic waves help bring the cold water to the surface Easterly trade winds strengthen and sea-surface temperatures (SST) drop below normal JL

26

27 Difference Between El Nino and La Nina
Both refer to large-scale changes in sea-surface temperature across the eastern tropical Pacific Sea surface readings off South America’s west coast range from the 60s to the 70s in degrees Fahrenheit, while they exceed 80 degrees Fahrenheit in the “warm pool” located in the central and western Pacific The “warm pool” expands to cover the tropics during El Nino, but during La Nina, the easterly trade winds strengthen and cold upwelling along the equator and west coast of South America intensifies Sea-surface temperatures along equator can fall to 7 degrees below normal JL

28 El Nino (December 1997) La Nina (December 2000) JL

29 Global Impacts Produces opposite climate variations from El Nino
Parts of Australia and Indonesia are prone to drought during El Nino, but are typically wetter than normal during La Nina JL

30 U.S. Impacts Often features drier than normal conditions in the Southwest in late summer through the subsequent winter Drier than normal conditions also typically occur in the Central Plains in the fall and in the Southeast in the winter The Pacific Northwest is more likely to be wetter than normal in the late fall and early winter with the presence of a well-established La Nina La Nina winters are usually warmer than normal in the Southeast and colder than normal in the Northwest JL

31 Occurrence and Length El Nino and La Nina occur on average every 3 to 5 years However, in the historical record, the interval between events has varied from 2 to 7 years La Ninas have been half as frequent as El Ninos Conditions typically last approximately 9 to 12 months Some episodes may persist as long as 2 years JL


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