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17 Cards in this Set
- Front
- Back
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Pytheas |
In the 4th century B.C. noted the drifting of ships |
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Sir John Murray |
surface water is always warmer than deep and a thermocline exists |
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currents |
mass flow of water both horizontal and vertical |
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surface current |
wind-driven movements of water at or near the ocean's surface |
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thermohaline currents |
depend on density differences caused by variations in water's temperature and salinity; slow deep currents that affect water below the pycnocline |
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what do currents influence? |
temperature, climate, and biological productivity |
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What causes the two major types of ocean currents? |
the surface currents are caused by the wind and the thermohaline currents are caused by the density differences (salinity and temperature) |
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How much of the world ocean is involved in surface currents? |
10% |
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surface currents |
water flowing horizontally in the uppermost 400m of the ocean's surface, driven by wind friction |
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what water do surface currents move? |
water above the pycnocline |
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gyre |
a circuit of mid-latitude currents around the periphery of an ocean basin |
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Which direction do waves go in the North? |
right |
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Which direction do waves go in the south? |
left |
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what are gyres divided into? |
interconnected currents that have distinct flow characteristics and temperatures. |
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What is the relative velocity of layers of water? |
each layer of water moves slower than the one above it |
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ekman spiral |
a theoretical model of the effect on water of wind blowing over the ocean. Because of the Coriolis effect, the surface layer is expected to drift at an angle 45 degrees to the right of the wind in the norther hemisphere. Water at successively lower layers drifts progressively to the right or left although not as fast as the surface flow. |
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what happens to the current when you reach a certain depth? |
at the friction depth, water flows in the opposite direction from the surface current. |
