Marine Ocean Current Notes

1. OCEAN CURRENTS:

2. CURRENT:
 Continuous and directed
movement of ocean water

4. TWO TYPES:
 Surface Currents
 Deep Water Currents

5. SURFACE CURRENTS:
 10% of water in ocean
 The upper 400m of the ocean

6. DEEP WATER CURRENTS:
 90% of water in ocean
 Waters move around the
ocean basins by density
differences
 Density differences a function
of different temperatures and
salinity

7. TWO TYPES OF FORCES:
 Primary Forces: Start the
water moving:
 Solar Heating
 Winds
 Gravity
 Coriolis Effect
 Secondary Forces: Influence
where the current goes

8. SOLAR HEATING:
 Causes water to expand
 Water is about 8 cm higher
than middle latitudes, thus
water wants to flow down
slope

9. WINDS:
 Winds blowing on surface of
the ocean push the water
 Water piles up in the direction
the wind is blowing

10. GRAVITY
 Will pull water “down the hill”
when water mounds up

11. CORIOLIS EFFECT:
 An inertial effect due to the
spinning of the earth
When going towards pole
you are coming from an
area that is moving faster,
thus the deflection with the
direction of the Earth’s
rotation
When going to the equator,
the deflection goes against
the spin of the Earth, due to
the spin of the Earth

12. GYRES:
 The effect of winds and
Coriolis effect results in
circular flows of water made
of several currents

13. EKMAN TRANSPORT:
 Surface water is
blown away by
winds, dragging
the water beneath
it
 The deflection due
to Coriolis Effect
creates a spiral
pattern and a net
current to the right
or left of wind
 Results in

14. UPWELLING:
 Nutrient rich water from the
deeper parts of the ocean
rises to the surface to replace
the water blown away
 Animation:

15. DEEP WATER CIRCULATION:
 Occur where the temperature
is cold and relatively high in
salinity
 Thermohaline Circulation
Thermo = heat, haline = salt

16. EARTH CONVEYOR BELT
 Salt rich, warm water is blown
north by the Gulf Stream, where
is cools and sinks
 This provides heat to the polar
regions and nutrients
everywhere
Possibly disrupted by global
warming

18. LOCAL CURRENTS:
 formed by a combination of
tides, winds, waves, and
rivers/streams
 Longshore currents and rip
currents

19. LONGSHORE CURRENTS:
 When waves strike the
shoreline at an oblique angle,
causing resultant waves to
move parallel with the
shoreline

20. RIP CURRENTS:
 Formed when waves push the
water in front of it sideways
till it can find a path out to sea