Ocean Currents

Two Types of Currents   Density Driven (deep water) Currents Wind Driven (surface) Currents

Density Driven Currents    Move water vertically through the ocean Density differences cause deep water currents   Dense water sinks at the poles Less dense water rises at the equator This process creates circulation throughout the oceans of the world

Surface Currents  Winds are primary energy source for surface currents.

  Winds blow across the ocean surface friction between the wind and the ocean surface drags the water along

Which way does the water flow?

  Rotation of the earth changes path of air and water (Coriolis Effect) Water flows to the right (clockwise) in Northern Hemisphere

Northern Pacific Surface Currents Kuroshio Current California Current North Equatorial Current South Equatorial Current East Australian Current Peru Current West Wind Drift Equator

Global Surface Currents   Most ocean currents have a dramatic impact on local weather and continental climate patterns Ex: Mediterranean climate zones

Surface Currents in the US The California Current is cold and comes from Alaska San Francisco Washington, DC The Gulf Stream is warm and comes from the equator/ Gulf of Mexico

What is a gyre?

  A roughly circular pattern of ocean surface currents Caused by the Coriolis Effect

North Pacific Gyre Equator

Why are gyres/ currents important?

  Warm currents move heat from the equator to middle and high latitudes Gyres influence air temperature, weather and climate of every continent