Why does the water in the eastern Pacific get warmer causing the El Niño phenomenon?

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Over the Pacific Ocean, westward moving trade winds push the warm water on the surface of the ocean to the west from the east. This causes warm water to accumulate on the west side of the Pacific Ocean. As the warm water from the surface of the eastern Pacific is...

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Over the Pacific Ocean, westward moving trade winds push the warm water on the surface of the ocean to the west from the east. This causes warm water to accumulate on the west side of the Pacific Ocean. As the warm water from the surface of the eastern Pacific is pushed to the west, cold waters are pushed up towards the surface. Because of this, there is a difference in temperature across the Pacific Ocean, in which the water in the western Pacific is warmer than the water in the east Pacific.

In El Niño, the warm water in the west Pacific heats the air around it, making the warm air rise, causing a circulation of air in which humid, warm air rises in the west Pacific, and cold air descends in the east, effectively bringing rise to east-bound winds, which weaken the westward trade winds. With the weakening of these westward trade winds, less warm water is pushed westward, and less cold water rises to the surface in the east, making the water temperature in the eastern Pacific comparatively warmer compared to its usual temperature. As the westward trade winds get weaker and weaker due to air circulation caused by heating of air in the west, the Pacific Ocean gets warmer and warmer in the east. This effect is El Niño, the (relative) heating of the eastern Pacific.

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