Entenda o El Niño e a La Niña (célula de Walker) | Ricardo Marcílio

Summary

The video explains the complex phenomena of El Niño and La Niña, focusing on their causes, effects, and the impact on global weather patterns and ecosystems. It describes how El Niño occurs due to weakened trade winds, leading to warmer Pacific waters, disrupting marine life and causing droughts and floods in various regions. In contrast, La Niña strengthens the trade winds, cooling the waters and creating opposite weather effects. The speaker emphasizes the unpredictability and widespread consequences of these phenomena, highlighting their influence on fishing, rainfall, and drought patterns across different continents.

Takeaways

• 😀 El Niño is caused by the weakening of trade winds, leading to the warming of the Pacific Ocean and a lack of upwelling of cold water.
• 😀 When trade winds weaken during El Niño, the cold, nutrient-rich water is no longer pushed to the surface, disrupting ecosystems, especially fisheries.
• 😀 El Niño’s consequences include reduced fish populations in Peru and Chile, due to warmer waters that lack oxygen.
• 😀 In Australia, El Niño causes droughts due to a lack of warm water being pushed to the east coast, leading to less evaporation and rainfall.
• 😀 In Brazil, El Niño exacerbates droughts in the northeastern backlands, making the already dry region even more arid.
• 😀 The term 'El Niño' is derived from the idea of a punishment from baby Jesus, as fishermen noticed a drop in fish populations around Christmas time.
• 😀 El Niño is an unpredictable phenomenon, with no set cycle for when it will occur. It can happen at any time but usually starts in October and lasts until March.
• 😀 The opposite of El Niño is La Niña, where the trade winds strengthen, causing the Pacific Ocean to cool and increasing upwelling of cold water.
• 😀 La Niña benefits fishing industries in Peru and Chile due to the rise in cold, oxygen-rich water that attracts more organic matter.
• 😀 In La Niña years, Australia experiences more rain and floods due to the stronger trade winds pushing warm water to the east coast, increasing evaporation and rainfall.
• 😀 In Brazil, La Niña leads to more rainfall in the northeastern backlands and a drier climate in the southeast and south of the country.

Q & A

What is the El Niño phenomenon, and how does it occur?

El Niño is an irregular climatic phenomenon that occurs due to the weakening of the trade winds, which normally push warm surface water in the Pacific Ocean toward the west. When the trade winds weaken, warm water stays in the central and eastern Pacific, causing a rise in sea surface temperatures. This disruption results in altered weather patterns globally.

What is the role of the Walker Cell in the normal climatic system?

The Walker Cell is a circulation of winds in the Pacific that moves air from the subtropical regions towards the equator. This movement causes warm surface water to be pushed westward and cold water to rise up from the deeper ocean, creating a natural upwelling that supports marine life and fishing industries.

How does the upwelling process work in the Pacific Ocean?

Upwelling occurs when the trade winds push warm surface water westward, causing cold, nutrient-rich water from the deeper ocean to rise. This cold water is denser, rich in oxygen, and supports the growth of organic matter, benefiting marine ecosystems and fishing industries, especially along the coasts of South America.

What happens to the Pacific Ocean waters during an El Niño event?

During an El Niño event, the trade winds weaken, reducing the upwelling of cold water. This causes warm surface water to accumulate in the central and eastern Pacific, which disrupts the normal ocean and atmospheric processes, leading to changes in weather patterns such as droughts, floods, and disruptions in fishing.

Why is the El Niño phenomenon associated with Christmas in South America?

The phenomenon is associated with Christmas because fishermen in countries like Peru and Chile noticed a significant drop in fish populations around the holiday season. This led to the belief that El Niño was a punishment from Baby Jesus, symbolizing a time when fish would 'disappear' from the sea, particularly around Christmas.

How does El Niño impact fishing industries in South America?

El Niño disrupts the upwelling of cold, oxygen-rich water, leading to a decrease in fish populations along the western coasts of South America, particularly in countries like Peru and Chile. This results in a significant reduction in fishing catches, negatively affecting the local fishing industries.

What are the key consequences of El Niño for Australia?

El Niño causes a reduction in rainfall on the eastern coast of Australia due to the absence of the trade winds pushing warm water westward. This leads to drought conditions and a higher likelihood of fires in the region, particularly in areas like Queensland.

How does El Niño affect Brazil's weather, especially in the northeastern regions?

In Brazil, El Niño exacerbates droughts in the northeastern backlands due to the weakening of the trade winds, which affects the wind circulation and reduces rainfall. This creates more intense periods of dry weather, aggravating the already dry conditions in the region.

What happens to the weather in Brazil's south and southeast during an El Niño event?

In the south and southeast of Brazil, El Niño typically leads to increased rainfall due to the stronger penetration of the Amazon's humid air mass (MAC) into these regions. This can result in wetter conditions and may cause flooding in some areas, like São Paulo during the early 2010s.

What is the opposite of El Niño, and how does it affect global weather?

The opposite of El Niño is La Niña, which occurs when the trade winds strengthen, leading to cooler Pacific waters. This causes opposite weather effects, such as more rainfall in eastern Australia, more oxygen-rich waters benefiting fishing, and increased rainfall in Brazil's northeastern backlands. La Niña also leads to drier conditions in the southern and southeastern regions of Brazil.