I. Global Winds and Ocean Currents. A. Origin of Ocean Currents. Drag exerted by winds flowing across the ocean causes the surface layer of water to move. Winds are the primary cause of surface ocean currents. Planetary Winds. Interaction of: Mid-Latitude southwesterly winds
a) North and south of the equator and are westward moving currents.
b) Derive energy from the trades winds
c) Affected by the Coriolis Effect (clockwise spiral in Northern Hemisphere and counterclockwise in the Southern Hemisphere)
d) Found in each of the major ocean basins and centered around the subtropical high pressure systems.
(i) A zone of rapid temperature change between:
(ii) Two Thermoclines
(iii) Changes as a result of seasonal heating by the Sun
Warm poleward flow is balanced by
sinking cold water at high latitudes that
moves towards the equator (conveyer).
Term for this over-turning circulation
(i) Term is derived from the two processes that control deep water formation and influence the water’s density.
Hopedale, Newfoundland and Labrador
Latitude = 55.45o N
Avg. Temp. = 28.4o F (-2.0o C)
Latitude = 58.22o N
Avg. Temp. = 46.9o F (9.4o C)
Climate scientists really don’t know the answer!
a) Initiated by surface winds
b) Assisted by the Coriolis Effect
c) Intermediate depth water moves upward to replace surface water that has been pushed away by winds
c) Cooler water moves upwards from below to replace the surface water
a) Common along the coasts of California, Peru, and West Africa.
b) Winds flow toward the equator parallel to the coast
(i) The Coriolis effect directs surface water away from shore.
(ii) Surface water is replaced by water that slowly rises from below (from 50
to 100 meters).
(iii) This water is cooler than the surface water it replaces.
c) This water is cooler
than the surface
water it replaces
d) Upwelling brings to the surface greater concentrations of dissolved nutrients
(i.e. nitrates and phosphates) that promote plankton growth, which supports
A. Precipitation on a “uniform” Earth without considering variations caused by land and water
Satellite Image of a well-developed mid-latitude cyclone over the British Isles.
Have Different Characteristics on Eastern and Western Sides