Final answer:
El Niño is the warm phase of ENSO with a band of warm ocean water in the Pacific leading to high pressure in the western Pacific, and La Niña is the cool phase with below-average SST contributing to high pressure in the eastern Pacific. Both phases influence global weather, but El Niño tends to have more severe consequences such as extreme weather events, impacting economies reliant on agriculture and fishing.
Step-by-step explanation:
El Niño and La Niña
a) What is El Niño? El Niño is the warm phase of the El Niño Southern Oscillation (ENSO), marked by a band of warm ocean water that develops in the central and east-central equatorial Pacific. It is characterized by high air pressure in the western Pacific and low air pressure in the eastern Pacific, leading to significant changes in global weather patterns.
b) What is La Niña? La Niña represents the cool phase of ENSO, occurring when Sea Surface Temperature (SST) in the eastern Pacific is below average. This phase is recognized by high air pressure in the eastern Pacific and low in the western Pacific, also affecting global weather but generally in the opposite way of El Niño.
c) Differences in impact on global weather patterns While El Niño and La Niña are part of the same cycle, they differ in their impacts. El Niño tends to cause extreme weather such as floods, droughts, and fires, which can lead to crop failures and economic impacts, especially in farming and fishing industries. La Niña typically has less extensive and damaging effects, but can still contribute to global changes in temperatures and rainfall patterns.