El Nino & La Nina



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El Nino pattern.

Normally, the winds flow from East to West, and push the warm sun heated surface water from California over to the other side of the Pacific. So much so that the ocean level in the Western Pacific is usually 24 inches higher and 14o warmer than that of the Eastern Pacific!

As the warm surface water leaves, it is replaced with cold, nutrient rich water from the deep. This is called an upwelling. Upwellings support a large variety of organisms. The nutrients bring in a lot of small fish, which leads to a lot of food for the big fish…you get the idea.



Impact of El Nino

During an El Nino pattern, the winds weaken or reverse, so warm water is pushed towards the South & North American western coasts (instead of away) and causes the surface water to heat up there.



Since wind isn’t pushing the warm way away, El Nino suppresses upwellings, resulting in less food for predators AND fisherman too.

El Nino can also lead to extreme weather changes. On continents, El Nino can make some location more wet and cool, and other locations more dry and warm. Because ocean surface temps are warmer in the Pacific, this can lead to more hurricanes or more damaging hurricanes (hurricanes require warm water…the more warm water, the higher the # and or strength of hurricanes). Check out the map below to see how you might be impacted by El Nino.

We still don’t understand WHY this happens and can’t even really predict WHEN they will occur. Typically happen every 5-7 years, but not always. They usually last for about a year. They can also change in their severity. Oh El Nino, if only we knew why!



So far we have only talked about El Nino’s effect on the PACIFIC Ocean. What about the Atlantic? Well funny thing…during El Nino events, the surface temps of the Atlantic ocean typically COOL down. As the Atlantic cools, this suppresses hurricanes there. All this goes to show us that the Earth is very complicated and we still have a lot of studying to do to unlock secrets here on Earth.

LA NINA

Let’s make this easy. It is the EXACT opposite of El Nino. So the Pacific experiences unusually COOL surface water temperatures along the California coast as the trade winds speed up, which makes for larger than usual upwellings along the coasts of California and South America. Hurricane activity in the Pacific declines these years. The surface temps of the Atlantic Ocean however begin to WARM up, which means more (and potentially stronger!) hurricanes there. And no, we don’t understand how or why this happens either.

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