Currents and Climate Chapter 5 Lesson 2 Miss Cook February, 2012

 Surface Currents greatly affect the climate in many parts of the world.  Some surface currents warm or cool coastal areas year-round  Other surface currents sometimes change their circulation patterns.  Changes in circulation patterns cause changes in atmosphere that affect the climate in many parts of the world Surface Currents and Climate

 The temperatures of surface currents vary.  Surface currents are classified as: Warm-water Currents Cold-water Currents Figure 1 Warm-Water Currents and Climate

 Cold-Water Currents also affect the climate of the land near where they flow  Figure 2: The California current carries cold water from the North Pacific Ocean southward to Mexico. Cold-Water Currents and Climate

 Upwelling– the movement of deep, cold, and nutrient-rich water to the surface  When local wind patterns cause local surface currents to move away from the shore, the warm water is replaced by deep, cold water.  This causes upwelling to occur in the eastern Pacific Upwelling

 The nutrients that are brought up to the surface of the ocean support the growth of phytoplankton and zooplankton.  These tiny plants and animals support other organisms such as fish and seabirds. Why is Upwelling Important?

 El Nino---a change in the water temperature in the Pacific Ocean that produces a warm current  This happens every 2 to 12 years  El Nino can last for a year or longer and changes the interaction of the ocean and the atmosphere  Changes global weather patterns What is El Nino?

 La Nina—a change in the eastern Pacific Ocean in which the surface water temperature becomes unusually cool  El Nino is sometimes followed by La Nina—this also affects weather patterns What is La Nina?

 Flash floods  Mudslides  Droughts  During El Nino, upwelling of nutrient-rich water does not occur off the coast of South America, which affects the organisms that depend on the nutrients for food. Effects of El Nino