10. Hydrosphere: Circulation of the World Ocean

Photo 19: Warm ocean currents in the Caribbean, close to Cancun, Mexico. 2008-12-18

Ocean Currents

To transport heat from the warmer Equatorial Regions (photo 19) to the cooler Polar Regions (photo 20), both Ocean currents (13%) and air movement (87%) are involved. However, the oceans currents near the Equator are actually more involved in heat movement and account for 25% of the total heat transfer in that area. Interestingly, most of the heat is transported in the upper 100 meters of ocean water at a speed of about 8 kilometers per hour. Ocean currents are caused by the frictional force of the wind, by the Coriolis force, by moving against and around landmasses, and by salinity differences (saltier water is heavier). 

Photo 20: Powerful Westerlies: A day on the beach in The Netherlands. 2009-05-17

North Atlantic Oscillation

Air and water flow is not so universal and has unique systems for various parts of the earth. El Niños affect the tropical climate and weather of the Southern Pacific. The North Atlantic Oscillation (NAO) is a similar phenomenon of the North Atlantic Ocean. It depends on how much warm water comes from the Gulf of Mexico and the Caribbean area, it depends on how much of this warm water makes it over to Northern and Central Europe, and it depends on the existence of the Icelandic low pressure system and the Bermuda High pressure system. When these conditions are in place, and they can sometimes endure for years, strong warm air Westerlies blow into Britain, France, The Netherlands (photo 20), and other European countries. If these conditions do not exist, cold air from Russia will enter this area of Europe.