CHAPTER 14: OCEAN CURRENTS WHAT IS A CURRENT? The mass movement or flow of ocean water … envision a river flowing within the ocean Ocean currents can be divided into two types: Surface—occurs in shallow water Density—occurs in deep water

SURFACE CURRENTS- Are caused by the wind blowing across the ocean Move in the upper ½ mile of the ocean and affect about 20% of the ocean’s total volume Surface currents can be warm or cold Warm surface currents move from the equator to the poles Cold Surface currents move from the poles to the equator

Red are warm currents Blue are cold currents

FACTORS THAT INFLUENCE SURFACE CURRENTS 1. Coriolis Effect: caused by the earth’s rotation. In the northern hemisphere things turn clockwise. In the southern hemisphere things turn counterclockwise

Continents: Currents will deflect off continents. In the northern hemisphere…east coast currents are warm and west coast currents are cold.

D. Antarctic Subpolar Which ocean current is not deflected? Benguela C. East Australia North Pacific D. Antarctic Subpolar

The Gulf Stream (surface current) moves five hundred times as much water as the Amazon. Warmed by the Caribbean sun, it flows northwards along the North American coastline until it reaches sub polar waters. Greenland Iceland

The Gulf Stream is the “red river” HOW SURFACE CURRENTS AFFECT CLIMATE Oceans absorb more of the suns radiation than land. Water retains heat longer than land, therefore, the oceans play a major part in determining the type of weather across the Earth Examples: Winnipeg and Cork, Ireland’s mild climate is due to heat the Gulf Stream brings to it! The Gulf Stream is the “red river”

Surface Currents affect weather....Gulf Stream’s affect on Winnipeg and Cork Greenland Iceland Average Temperature 1 Daily Sunshine (hours) 3.86 Average Total Rainfall (in.) Trace Average Wind Speed (mph) 11 mph Average No. Days w/Snow/Sleet 15 Average Total Snowfall (inches) 8.8 in Average Temperature 41 Daily Sunshine 2 hours Average Total Rainfall (in.) 5 ½ in. Average Wind Speed (mph) 15 mph Average No. Days w/Snow/Sleet 4.5 Average Total Snowfall (inches) Trace

STOP SURFACE CURRENTS LAB…. HAND OUT MAP AND FILL IN CURRENTS Then do questions

ON YOUR MAP DRAW A BLACK LINE AT THE EQUATOR… THE 0º LATITUDE LINE… THIS SEPERATES THE NORTHERN HEMISPHERE FROM THE SOUTHERN HEMISPHERE

WARM CURRENTS Winnipeg Cork

COLD CURRENTS Winnipeg Cork

Winnipeg Cork

COLD SURFACE CURRENTS GREENLAND LABRADOR OYASHIO CANARY CALIFORNIA Cork Winnipeg CANARY CALIFORNIA BENGUELA WEST AUSTRALIAN WAC PERU ANTARCTIC CIRCUMPOLAR COLD SURFACE CURRENTS

WARM SURFACE CURRENTS NORWEGION ALASKA GULF STREAM KUROSHIA AGULHAS Cork Winnipeg ALASKA GULF STREAM KUROSHIA AGULHAS MOZAMBIQUE BRAZIL EAST AUSTRALIAN EAC WARM SURFACE CURRENTS

DEEP OCEAN OR DENSITY CURRENTS These currents occur in deeper waters than the surface currents They occur due to the differences in densities of seawater The temperature and the amount of salt in ocean water affects its density STOP HERE TO CONDUCT LAB!!!

Lab results From top to bottom: Red (Hot, no salt) Room Temp water Blue (Cold, no salt) Yellow (room temperature salt water)

Cold, salty water is heavier and sinks Warm, less salty water rises This movement creates a convection current in ocean water much like the one in the picture Cold Water Sinking Warm Water Rising

Density Currents cause a process that is known as upwelling Density Currents cause a process that is known as upwelling. Upwelling is when deep cold nutrient filled water is brought to the surface. Fishermen look for upwelling currents because you find fish feeding on these nutrients.

What happens when Upwelling Does Not Occur? El Nino —A warming of the ocean surface off the western coast of South America that occurs every 4 to 12 years when upwelling of cold, nutrient-rich water does not occur. It affects Pacific jet stream winds, altering storm tracks and creating unusual weather patterns in various parts of the world. Normal Heavy rainfall is confined to the warm (red) waters surrounding Indonesia at the western end of the Pacific. The easterly surface winds weaken and retreat to the eastern Pacific, allowing the central Pacific to warm, and the rain area to migrate westward. El Nino

AMAZING EARTH SCIENCE FACTS Currents move from ________________ areas _____________ brings cold, nutrient rich water from the bottom of the ocean to the surface. This is rich in biological activity. The ____________ is the largest reservoir of heat at the Earth’s surface. It drives the ____________ patterns of the Earth cold to warm Upwelling ocean weather