in normal years, atmospheric pressure is greater in the eastern pacific than in the western pacific....
TRANSCRIPT
In normal years , atmospheric pressure is greater in the eastern Pacific than in the western Pacific.
The trade winds blow surface water from east to west.
Warm water "piles up" in the western Pacific and sea level is higher than it is in the east.
Upwelling of cold, nutrient-rich water occurs along the western coast of South America
More nutrients = more phytoplankton = food fishing
First noticed off coast of Peru around Christmas, El Niño refers to the Christ child◦ Occurs every 2 – 7 years
Unusual and atmospheric conditions◦ Trade winds slack off or reverse◦ Warm water moves eastward◦ Upwelling slacks off or stops completely
Compare the thermocline from normal conditions (above) to El Niño (below)
Western Pacific (ex. Indonesia) does not get rain◦ No monsoon season ◦ Drought◦ Fires
Eastern Pacific (ex. South America)◦ Tropical thunderstorms◦ Flooding
Opposite effects of El Niño
Stronger winds
Colder temperatures
El Niño Warmer ocean temps
Occurs every 3-7 years
Wetter than normal summers
Weak trade winds
Fewer Atlantic hurricanes
La Niña Colder ocean temps
Frequency unknown
Drier than normal summers
Strong trade winds
Increased hurricane activity in Atlantic