×

El Nino - Oceanic and Climatic Phenomenon

Top
Download PDF
FAQ

El Nino Effect

Bookmark added to your notes.
View Notes
×

El Nino is a climate pattern in the Pacific Ocean that has the capability of significantly affecting the weather worldwide. During the period of El niño, trade winds weaken, and the warm water is pushed back in the direction of east, toward the west coast of the Americas. The warmer waters induce the Pacific jet stream to move towards the south of its neutral position. As with the shift, regions in Canada and the northern United States are warmer and drier than usual. But in the United States Gulf Coast and Southeast, these episodes are wetter than usual and experience increased flooding.


What are El Nino and La Nina?

Similar to El Nino, La Nina is a weather regime in the Pacific Ocean that can significantly affect the weather worldwide. During normal atmospheric conditions in the Pacific Ocean, trade winds blow towards the west along the equator, carrying warm water towards Asia from South America. To replace that warm water, cold water springs up from the depths — a process known as the upwelling. Having said that, El Nino and La Nina are two opposing weather patterns that suspend or stop these normal conditions. Scientists call such circumstances as the El Nino-Southern Oscillation (ENSO) cycle. La Nina and El Nino phenomenon can both have global impacts on weather, wildfires, environment, ecosystems, and economies. Episodes of El Nino and La Nina essentially last nine to 12 months but can also periodically last for years. El Nino and La Nina events take place every two to seven years, but they don’t transpire on a regular schedule. Usually, El Nino takes place more often than La Nina.


Causes of an El Niño

Scientists have still not been able to understand exactly what stimulates an El Niño cycle. Not all El Niños are alike, nor do the ocean and atmosphere always follow similar patterns from one El Niño to another.

"There isn't one major cause, which is one of the reasons as to why we can't foresee this thing perfectly. "There is some sort of anticipation in the common characteristics that occur with El Nino, which is why we can make predictions of it. But it won't be exactly alike every time."


How to Forecast El Niño?

For predicting an El Niño, scientists keep under observation the temperatures in the upper 656 feet of the ocean. They monitor for the telltale temperature movement from the western Pacific to the eastern Pacific Ocean. For instance, during the 2014 spring, a very powerful warm water swell termed as a "Kelvin wave" passed through the Pacific, guiding some forecasters to predict a strong El Niño for winter 2014. But, their forecast fizzled by fall since the storms and trade winds never followed suit, and the reviews between ocean and atmosphere failed to flourish.


Effects of El Nino

El Nino induces the Pacific jet stream to shift south and stretch out to east further. During winter, this steers to wetter circumstances than normal in the Southern U.S. and drier and warmer conditions in the North.

El Nino also imposes a powerful effect on marine life off the Pacific coast. During normal climatic conditions, upwelling raises water from the depths to the surface; this water is soothingly cold and nutrient rich. In the episodes of El Nino, upwelling weakens or halts altogether. Without the nutrients brought up from the deep, there are some phytoplanktons off the coast. This exerts influence on fish that eat phytoplankton and, conversely, affects everything that eats fish. The warmer waters can also bring tropical species, like albacore tuna and yellowtail, into regions that are usually too cold.


Fun Facts on El Nino

  • El Nino implies Little Boy or Christ Child in Spanish.

  • The full name used was El Nino de Navidad, since El Nino literally peaks around December against the disposition of the phenomenon to arise around Christmas

  • During the 1600s, South American fishermen first observed periods of peculiarly warm water in the Pacific Ocean.

  • Climate records of El Nino date back to millions of years, with evidence of the cycle found in coral, caves, ice cores, deep-sea muds, and tree rings.

FAQ (Frequently Asked Questions)

1. How often Does the El Nino Phenomenon Occur?

Answer: El Nino phenomenon occurs every 3 to 5 years but may come as often as every two years or as seldom as every seven years. Essentially, El Niños current takes place more frequently than La Niñas. Each episode generally lasts 9 to 12 months. They commonly start off to form in spring, reach peak intensity between December and January, and then perish by May of the following year.


Their El Nino current strength can vary substantially between cycles. One of the most powerful in recent decades was the El Niño that formed during the winter of 1997-98. "Everyone linked the word El Niño with that event, but that was a rare, once-in-a-century event".

2. What Happens in the Absence of El Niño?

Answer: Under normal conditions, non-El Niño circumstances, trade winds blow toward the west through the tropical Pacific, away from South America. These winds gather warm surface water in the west Pacific, in such a way that the sea surface is about 1 to 2 feet higher offshore Indonesia than to the other side of the Pacific, offshore Ecuador.


The sea-surface temperature is also about 8°Celsius (14 °Fahrenheit) warmer in the west. Cooler ocean weather exercise control over offshore northwest South America, because of an upwelling of cold water from deeper levels. This nutrient-rich cold water backs up major fisheries and diverse marine ecosystems.