8.3 Ocean Currents

El Nino

What? a warming of the water temperature in the eastern Pacific Ocean WHY? due to weakening of trade winds causing warm water to move eastward Effects? South America has flooding/Australia has droughts

La Nina

What? the Eastern Pacific Ocean has cooler surface water temperatures than normal Why? strong warm trade winds blow warmer surface waters towards Australia Effects? South America has droughts/Australia has flooding

cold ocean currents

cause climates to be colder than usual

warm ocean current

cause climates to be warmer than usual

convection current

circulation movement of air or water due to unequal heating of the SUN; Warm material becomes less dense and rises, cooler material becomes more dense and sinks.

global winds

direction of these winds affects the movement of surface currents

ocean currents

movement of ocean water that flows in a stream-like pattern

deep ocean current (thermohaline)

ocean currents far below the surface; depend on DENSITY of water due to temperature or salinity (NOT wind)

surface currents

ocean currents that occur at or near the surface and are AFFECTED BY WIND; areas near a WARM current will be WARM due to current starting at the equator; areas near a COLD current will be COLD due to current starting at the poles

upwelling

process that causes cold, nutrient rich water from the deep ocean to rise to the surface, replacing the warm water

Coriolis effect

rotation of the Earth causes ocean currents to circulate clockwise (to the right) in the Northern Hemisphere and counterclockwise (to the left) in the Southern Hemisphere

salinity

the amount of dissolved salt in water

SUN

the source of energy for convection currents which causes WINDS and OCEAN CURRENTS

Gulf Stream

warm ocean current that affects weather in the southeastern U.S.