AP®︎ Environmental Science: Topic 4.9 Flashcards

Recurring coupled changes in the tropical Pacific Ocean and atmosphere, with neutral, El Niño, and La Niña states that alter global weather and ocean circulation

The atmospheric component of ENSO: changes in Pacific air pressure, trade winds, and tropical convection coupled to ocean-temperature changes

The usual Pacific pattern: easterly trade winds, warm water and rainfall in the west, and cool, nutrient-rich upwelling in the east

ENSO’s warm phase: weakened trade winds shift warm water and rainfall eastward, deepen the eastern thermocline, and reduce nutrient-rich upwelling near South America

ENSO’s cool phase: strengthened trade winds push warm water westward, make the eastern thermocline shallower, and enhance cold, nutrient-rich upwelling near South America

East-west tropical Pacific circulation in which air rises over the warm western Pacific, moves east aloft, descends over the cooler east, and returns west at the surface

The rise of cold, nutrient-rich deep water to replace surface water moved away, supporting high primary productivity and productive fisheries

The ocean layer where temperature decreases rapidly with depth; its eastern Pacific depth controls how readily cold deep water reaches the surface

Links through atmospheric circulation by which ENSO changes in the tropical Pacific alter weather patterns in distant regions