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
TWO TYPES OF FORCES:
Primary Forces: Start the water moving:Solar Heating
Winds
Gravity
Coriolis Effect
Secondary Forces: Influence where the current goes
SOLAR HEATING:
Causes water to expand
Water is about 8 cm higher
than middle latitudes, thus
water wants to flow down
slope
WINDS:
Winds blowing on surface of
the ocean push the water
Water piles up in the direction
the wind is blowing
CORIOLIS EFFECT:
An inertial effect due to the
spinning of the earthWhen 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
GYRES:
The effect of winds and
Coriolis effect results in
circular flows of water made
of several currents
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 upwelling
UPWELLING:
Nutrient rich water from the
deeper parts of the ocean
rises to the surface to replace
the water blown away
Animation:
DEEP WATER CIRCULATION:
Occur where the temperature
is cold and relatively high in
salinity
Thermohaline Circulation
Thermo = heat, haline = salt
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
LOCAL CURRENTS:
formed by a combination of
tides, winds, waves, and
rivers/streams
Longshore currents and rip
currents
LONGSHORE CURRENTS:
When waves strike the
shoreline at an oblique angle,
causing resultant waves to
move parallel with the
shoreline