PASADENA, Calif. -- The weather-altering La Nina phenomenon has all but vanished from the Pacific Ocean, satellite observations show. The pool of unusually cool tropical water marked by low sea levels has shriveled and the equatorial Pacific is warming to normal temperatures, NASA's Jet Propulsion Laboratory said.
Scientists cautioned that like its warm counterpart, El Nino, a La Nina condition will influence global climate and weather until it has completely subsided. La Nina has also shrunk several times and then had a resurgence over the past 12 months, they said.
The latest findings from the U.S.-French Topex-Poseidon satellite come from a 10-day cycle of data collection that ended June 18. The satellite's altimeter measures sea surface height as an indicator of temperature.
JPL scientists reported in May that Topex-Poseidon found an area of lower-than-normal sea levels and cool water stretching from the Gulf of Alaska down the west coast of North America.
That phenomenon -- unnamed and distinct from La Nina -- is persisting as summer begins in the northern hemisphere even though the trend is the opposite across most of the rest of the Pacific, where above-normal sea surface heights and warmer ocean temperatures appear to be increasing, JPL said.
This La Nina followed the historic 1997-98 El Nino.
For the United States, an El Nino brings unusually warm temperatures to the northern states and cooler, wetter conditions to the southern tier of states.
La Nina is linked to cooler conditions in central North America, and dry, warm conditions in the southern states.
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