El Nino - La Nina

Summary

The video explains how El Niño and La Niña form and how they influence global climate. Under normal Pacific conditions, strong trade winds push warm surface water westward, creating heavy rainfall near Indonesia and causing cold upwelling near South America. During El Niño, these trade winds weaken, allowing warm water to shift eastward, reversing weather patterns and bringing storms to the Americas. La Niña, by contrast, intensifies normal conditions, strengthening trade winds and increasing cold upwelling. The Pacific oscillates between these phases every two to eight years, driving significant climate variations worldwide.

Takeaways

• 😀 El Niño and La Niña are weather phenomena in the Pacific Ocean that significantly impact global weather patterns.
• 😀 Normally, strong southeast trade winds push warm water from east to west across the Pacific Ocean.
• 😀 The trade winds create a circulation system called the Walker Cell, leading to wet and rainy conditions in the western Pacific and dry conditions in the east.
• 😀 The warm water in the western Pacific is called the West Pacific Warm Water Pool, while cold water upwells in the eastern Pacific near South America.
• 😀 El Niño occurs when the southeast trade winds weaken or reverse, causing warm water to move back across the Pacific, leading to increased rainfall and storms along the western coast of the Americas.
• 😀 During El Niño, upwelling in the eastern Pacific ceases, resulting in warmer ocean temperatures and shifts in atmospheric pressure patterns.
• 😀 La Niña is the opposite phase, where the trade winds strengthen, pushing even more cold water to the west and intensifying the normal conditions of the Pacific.
• 😀 La Niña causes more upwelling along the South American coast, making the eastern Pacific cooler and drier while increasing rainfall in the western Pacific.
• 😀 The El Niño and La Niña cycles can vary in duration, typically occurring every two to eight years, but not on a regular schedule.
• 😀 These cycles have far-reaching effects on global climate, including rainfall, temperature, and storm patterns, especially in areas around the Pacific Ocean.

Q & A

What is the El Niño and La Niña cycle?

The El Niño and La Niña cycle refers to periodic changes in ocean temperatures and atmospheric conditions in the Pacific Ocean, which have significant impacts on global climate patterns, rainfall, and weather events.

How does the normal situation in the Pacific Ocean work?

Under normal conditions, strong southeast trade winds blow from east to west across the Pacific Ocean, pushing warm water toward the western Pacific, and allowing cold water to upwell near South America. This creates a large-scale circulation known as the Walker Cell.

What are the effects of the trade winds in the Pacific Ocean?

The trade winds push warm water from east to west across the Pacific, causing cold water to rise from below in the eastern Pacific. This leads to upwelling near South America and causes the western Pacific to accumulate a large pool of warm water.

What is the Walker Cell, and how does it function?

The Walker Cell is a large-scale atmospheric circulation that forms due to the trade winds. As the winds push warm water toward the western Pacific, low-pressure systems develop, causing rainfall in the region, while cold water rises in the eastern Pacific.

What is the West Pacific Warm Water Pool?

The West Pacific Warm Water Pool is a region in the western Pacific Ocean where water becomes very warm due to the accumulation of warm water from the east, creating a large body of warm water that fuels wet and rainy conditions.

What happens during an El Niño event?

During El Niño, the trade winds weaken or break down, allowing warm water to move back across the Pacific Ocean toward the eastern side, causing a reversal in atmospheric pressure patterns. This leads to increased rainfall, storms, and flooding along the Pacific coasts of North and South America.

What are the main weather impacts of El Niño?

El Niño typically brings heavy rainfall, storms, and flooding to regions along the Pacific coast from California to South America. It can also lead to changes in global weather patterns, affecting temperatures and precipitation in various regions around the world.

What occurs after an El Niño event?

After an El Niño event, conditions often swing back to a La Niña phase, where the trade winds strengthen and cold water upwelling intensifies along the South American coast, further reinforcing normal ocean conditions.

What is La Niña, and how is it different from normal conditions?

La Niña is an intensification of the normal conditions in the Pacific Ocean, where the trade winds become stronger, pushing more cold water westward. This increases upwelling near South America and further amplifies the difference between the warm western Pacific and the cooler eastern Pacific.

How often does the El Niño-La Niña cycle occur?

The El Niño-La Niña cycle occurs irregularly, typically every two to eight years. The timing and intensity of these events can vary, but they often alternate between the two phases, causing fluctuations in global climate patterns.