currents and climate chapter 5 lesson 2 miss cook february, 2012
TRANSCRIPT
Currents and Climate
Chapter 5 Lesson 2Miss 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