El Ni¤o: Is 2014 the new 1997?
 
May 19, 2014:  Every ten days, the NASA/French Space Agency Jason-2 satellite
maps all the world's oceans, monitoring changes in sea surface height, a
measure of heat in the upper layers of the water.   Because our planet is more
than 70% ocean, this information is crucial to global forecasts of weather and
climate.
 
Lately, Jason-2 has seen something brewing in the Pacific-and it looks a lot
like 1997.
 
"A pattern of sea surface heights and temperatures has formed that reminds me
of the way the Pacific looked in the spring of 1997," says Bill Patzert, a
climatologist at NASA's Jet Propulsion Laboratory. "That turned out to be the
precursor of a big El Ni¤o."
 
http://www.youtube.com/watch?v=zaxPwASV2kY
 
A new ScienceCast video examines the evidence that an El Ni¤o is developing in
the Pacific.  Play it
 
"We can't yet say for sure that an El Ni¤o will develop in 2014, or how big it
might be," cautions Mike McPhaden of NOAA's Pacific Environmental Research
Laboratories in Seattle, "but the Jason-2 data support the El Ni¤o Watch
issued last month by NOAA."
 
What Jason-2 has been seeing is a series of "Kelvin waves"-massive ripples in
sea level that travel across the Pacific from Australia to South America. 
Forecasters are paying close attention because these waves could be a herald
of El Ni¤o.
 
The two phenomena, Kelvin waves and El Ni¤o, are linked by wind. Pacific trade
winds blow from east to west, pushing sun-warmed surface waters toward
Indonesia.  As a result, the sea level near Indonesia is normally 45 cm higher
than it is near Ecuador.  Researchers call that area the "warm pool"-it is the
largest reservoir of warm water on our planet.
 
Sometimes, however, trade winds falter for a few days or weeks, and some of
that excess sea level   ripples back toward the Americas. "That's a Kelvin
wave," says McPhaden. "It's not unusual to see a couple every winter."
 
El Ni¤o happens when trade winds falter not just for days, but for many
months. Then Kelvin waves    cross the Pacific like a caravan, raising sea
level and leaving warmer equatorial waters in their wake.
 
http://tinyurl.com/2x23hp [NOTE: More of an article than an image]
 
On May 8th, the National Centers for Environmental Prediction forecasted a 65%
chance of El Ni¤o developing during the summer of 2014. More"The El Ni¤o of
1997/98 was a textbook example," recalls Patzert. "At that time we were
getting data from TOPEX/Poseidon, a predecessor of Jason-2.  Sea surface maps
showed a whitish bump, indicating a sea level some 10 centimeters higher than
usual, moving along the equator from Australia to South America."
 
"The same pattern is repeating in 2014," says McPhaden. "A series of Kelvin
waves generated by localized west wind bursts in the western Pacific that
began in mid-January 2014 are headed east. Excitement is building as a third
weakening of the Pacific trade winds happened in mid-April."
 
Ocean and atmospheric scientists at NOAA and NASA are carefully monitoring the
Pacific trade winds. The tipping point for declaring a significant El Ni¤o
will be an even longer lasting, larger collapse in Pacific trade winds,
possibly signaling a shift in weather all around our planet.
 
"It will become much clearer over the next two to three months whether these
recent developments are the forerunner of a major El Ni¤o-or any El Ni¤o at
all," says McPhaden.
 
"Jason-2 is a marvelous Kelvin wave counter," adds Patzert, "and it will tell
the tale."
 
Credits:
Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:
Science@NASA
 
Web Links:  The El Nino Winter of 1997-1998 -- a technical report from tthe
National Climatic Data Center Jason 2-- home page
 
 
Regards,
 
Roger

--- D'Bridge 3.99
 * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)