Ocean Currents

Mass movement or flow of ocean water Mass movement or flow of ocean water River within the ocean River within the ocean Two types Two types –Surface and Density (Deep)

Surface Currents Link Horizontal, stream-like movements of water that occur at or near the surface of the ocean Horizontal, stream-like movements of water that occur at or near the surface of the ocean Can reach depths of several hundred meters Can reach depths of several hundred meters Example: Gyres Example: Gyres

Surface Currents Controlled by three factors Controlled by three factors –Global winds –Coriolis Effect –Continental Deflections

Surface Currents Global Winds Global Winds –Cause surface currents to flow in the direction the wind is blowing –EX: Jet Stream Coriolis Effect Link Coriolis Effect LinkLink –The apparent curving of moving objects due to the Earth’s rotation

Surface Currents Coriolis Effect Coriolis Effect –Northern Hemisphere = clockwise –Southern Hemisphere = counter clockwise Continental Deflections Continental Deflections –Shape of continents change the direction of current flow

Density Currents Stream like movement of ocean water far below the surface Stream like movement of ocean water far below the surface Caused by Caused by – Differences in density –Change in temperature –Change in salinity

What Effects Deep Currents? Change in temperature Change in temperature –Decreasing the temperature of water increases density Change in salinity Change in salinity –Increasing the salinity of water increases density

Currents and Climate Warm water currents Warm water currents –Bring warm water to colder regions

Currents and Climate Cold water currents Cold water currents –Bring cold water to warmer regions

Why are Ocean Currents Important? They affect weather on a local scale and climate on a global scale. Evaporation enables rains to fall dependent upon currents. Currents redistribute heat throughout the globe – – Example: Gulf Stream brings warm air into England, making it warmer

Question 1 What is a surface current and what causes them? What is a surface current and what causes them?

Answer Surface currents move water horizontally – parallel to the Earth’s surface Surface currents move water horizontally – parallel to the Earth’s surface They are powered by wind They are powered by wind

Question 2 What is the Coriolis Effect? What is the Coriolis Effect?

Answer The Coriolis effect is the shifting of winds and surface currents caused by Earth’s rotation. The Coriolis effect is the shifting of winds and surface currents caused by Earth’s rotation.

Question 3 What is upwelling? What is upwelling?

Answer Upwelling is a vertical circulation in the ocean that brings deep, cold water to the ocean surface. Upwelling is a vertical circulation in the ocean that brings deep, cold water to the ocean surface.