What is El Niño (ENSO)?

Summary

El Nino, part of the ENSO (El Nino Southern Oscillation), is a weather pattern affecting the equatorial Pacific, causing fluctuations between high and low pressure areas. Normally, trade winds push warm water west, creating a wet Indonesia and dry South American coast. El Nino disrupts this, weakening winds and causing warm water to accumulate off South America, leading to increased rainfall and potential mudslides. It also impacts global climate, causing droughts and floods in various regions, affecting agriculture, fisheries, and even politics. The opposite effect, La Nina, brings drier conditions to the eastern Pacific and wetter to the west.

Takeaways

• 🌊 El Nino is a fluctuating weather pattern in the Pacific Ocean around the equator, part of the ENSO (El Nino Southern Oscillation) system.
• 🔄 Southern Oscillation refers to weather changes in the Southern Hemisphere, which is interconnected with El Nino.
• 🌀 Normal weather patterns involve high pressure in the southeast Pacific, with trade winds moving warm water westward and cold water upwelling off South America.
• 🏜 The west coast of South America is typically dry due to cold upwelling waters, while Indonesia's east is wet due to warm waters.
• 🌡 Wind, air pressure, and sea temperature are interdependent, reinforcing the normal weather pattern.
• 🌀 A decrease in wind strength can initiate El Nino, reducing the temperature difference between the eastern and western Pacific.
• 🔥 El Nino occurs every 2 to 7 years, with weakened trade winds causing warmer waters to linger off South America, leading to increased rainfall in typically dry areas.
• 🐟 Warmer waters during El Nino have less fish, affecting local fisheries, and are first noticed around Christmas, hence the name 'El Nino'.
• 🌧 Conversely, Indonesia experiences colder waters, higher air pressure, and drier conditions during El Nino.
• 🌍 El Nino has global impacts, influencing rainfall and temperature patterns in various regions, causing floods in some areas and droughts in others.
• 🌀 La Nina is the opposite effect of El Nino, with cooler than average waters in the eastern Pacific, leading to drier conditions there and wetter conditions in the west.

Q & A

What is El Nino and what does its full name represent?

El Nino is a fluctuating weather pattern around the equator in the Pacific, and its full name is ENSO, which stands for El Nino Southern Oscillation, referring to weather fluctuations in the Southern Hemisphere.

What is the normal weather pattern in the Pacific Ocean?

In a normal situation, there is a high-pressure area in the southeastern part of the Pacific Ocean. Trade winds blow east to west, taking cold seawater to the west where it heats up and creates a low-pressure area, causing air to rise and rain, especially over Indonesia.

How does the normal weather pattern affect the climate on the west coast of South America and eastern Indonesia?

The normal weather pattern results in the west coast of South America being dry due to cold seawater and promoting upwelling, while eastern Indonesia is very wet due to warm seawater.

What causes El Nino to occur?

El Nino occurs when the strength of the trade winds decreases, leading to less warm seawater being blown westward, which in turn causes less cold water to rise in the eastern Pacific, reducing the temperature difference and weakening the winds further.

How often does El Nino typically occur?

El Nino occurs approximately every 2 to 7 years.

What are the effects of El Nino on the temperature of the ocean water near South America?

During El Nino, the ocean water just west of South America warms up, sometimes by as much as 6 degrees Celsius more than the normal temperature, creating a low-pressure area and increased precipitation.

Why is El Nino associated with the name 'Christ child'?

El Nino is named after the Christ child, or 'El Nino' in Spanish, because South American fishermen noticed that the phenomenon often occurred around Christmas.

What is the opposite effect of El Nino called, and what does it represent?

The opposite effect of El Nino is called La Nina, which is Spanish for 'girl' and represents a situation where the seawater cools above average in the eastern Pacific, causing stronger winds to the west and a higher than normal temperature difference between the eastern and western Pacific.

How does El Nino impact global weather patterns?

El Nino affects global weather patterns by increasing rainfall and flooding in some areas like Peru, Ecuador, and parts of the United States, while causing droughts in others such as Indonesia, India, Southern Africa, and Australia.

What are the potential consequences of El Nino on agriculture and fisheries?

El Nino can greatly affect agriculture and fisheries by causing droughts or floods, leading to crop failures, reduced fish populations, increased food prices, and potentially famine and political consequences.

How does El Nino influence hurricane activity in the Atlantic and Pacific Oceans?

During an El Nino, there are fewer hurricanes in the Atlantic area but an increase in the number of hurricanes in the Pacific Ocean due to the increased heat and moisture in the atmosphere.