2015 and 1997 El Niños: Déjà vu, or Something New?
If you live anywhere El Niño has important impacts, you’ve heard forecasters say this year’s event looks just like the monster El Niño of 1997-98. NASA satellite images of the Pacific Ocean in November 1997 and November 2015 show almost identical, large pools of warm water in the eastern equatorial Pacific. The National Weather Service has forecast that impacts this winter will resemble those in 1997, when California and the South suffered floods, mudslides and tornadoes, while residents of the Upper Midwest saved $2 billion to $7 billion in heating costs throughout their unusually warm winter.
When it comes to El Niños, however, there are no identical twins. This year’s event hasn’t always resembled the ‘97 one. Satellite observations from early ‘97 and early ‘15 show conditions in the Pacific Ocean that were, well, oceans apart.
In its “normal” state, the Pacific is warm on the western side and cooler in the east. That’s what the ocean looked like in 1996 and early 1997. Conversely, over the past 18 months or so, satellite images have shown a large pool of warm water hovering around the equator in the central Pacific — neither west, as in a normal year, nor east, as in a typical El Niño.
“That warm patch started last year and it never disappeared. It’s very peculiar behavior,” said Tong Lee, an oceanographer at NASA’s Jet Propulsion Laboratory, Pasadena, California.
In the first decade of the 2000s, scientists began noticing that warm pools were appearing more frequently in the central equatorial Pacific. Since they look like El Niños but are in the wrong place, some began calling them “central Pacific El Niños.” Others use the name “El Niño Modoki,” Japanese for (roughly) “almost but not quite an El Niño.”
More: News