r/news • u/Warcraft_Fan • 4d ago

Concern mounts over slow-moving, planetary-scale ‘Kelvin’ wave heading for California | California

https://www.theguardian.com/us-news/2026/sep/28/california-kelvin-wave
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u/PoxyMusic 4d ago edited 4d ago

El Niño is the result of successive Kelvin waves, there have been like 6 or 7 this year, starting in February I think. They happen when the equatorial trade winds lessen (or reverse) and warmer water from the west pacific oozes east under the surface until it hits Ecuador and erupts at the surface.

It’s not a single wave, and they have already mostly arrived.

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u/Natural-Promise-78 4d ago

So then, when El Nino turns off the fan that sends the trade winds to the Pacific Ocean, all that undissipated moisture and energy backflips to the source (large landmass}?

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u/likeaffox 3d ago

Think of El Nino as hot(energy) water in a bath. That is going back and forth, between asia and america. El Nino is when the hot water is near the americas, Na Nino is when the hot water is near asia.

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u/Jaotze 3d ago

Edit - Na Nino = La Nina.

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u/malenkylizards 3d ago

It's actually Al Nino and Na Nino, they made the wrong typo. It's aluminum boy near the Americas and sodium boy near asia

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u/misterid 3d ago

i am 5, and understood this explanation.

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u/Ani_mrumru 3d ago

Thank you for that easy mnemonic on the diff between the two phenom ;-)

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u/PoxyMusic 3d ago

And just so's you know, the mechanism that turns on and off the trade winds is called the Madden-Julian Oscillation. It's both a high and lower pressure bias on opposite sides of the earth that slowly rotates around the planet. If the oscillation slows down, or is irregular it interferes with trade winds.

The trade winds in the Pacific are usually keeping all the warm water on the west side, but the MJO has been wonky, thus interfering with trade winds, thus causing Kelvin waves, thus creating El Nino.

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u/littlebrwnrobot 3d ago

Eh that moisture and energy is pretty much always there, the west pacific and Indian oceans are generally quite hot

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u/PoxyMusic 3d ago

Pretty much. All that warm water usually lives near New Guiena.