From the University of Hawaii ‑ SOEST:
Climate researchers discover new rhythm for El Niño
El Niño wreaks havoc across the globe, shifting weather patterns that spawn droughts in some regions and floods in others. The impacts of this tropical Pacific climate phenomenon are well known and documented.
A mystery, however, has remained despite decades of research: Why does El Niño always peak around Christmas and end quickly by February to April?
Now there is an answer: An unusual wind pattern that straddles the equatorial Pacific during strong El Niño events and swings back and forth with a period of 15 months explains El Niño’s close ties to the annual cycle.
This finding is reported in the May 26, 2013, online issue of Nature Geoscience by scientists from the University of Hawai’i at Manoa Meteorology Department and International Pacific Research Center.
“This atmospheric pattern peaks in February and triggers some of the well-known El Niño impacts, such as droughts in the Philippines and across Micronesia and heavy rainfall over French Polynesia,” says lead author Malte Stuecker.
When anomalous trade winds shift south they can terminate an El Niño by generating eastward propagating equatorial Kelvin waves that eventually resume upwelling of cold water in the eastern equatorial Pacific. This wind shift is part of the larger, unusual atmospheric pattern accompanying El Niño events, in which a high-pressure system hovers over the Philippines and the major rain band of the South Pacific rapidly shifts equatorward.
With the help of numerical atmospheric models, the scientists discovered that this unusual pattern originates from an interaction between El Niño and the seasonal evolution of temperatures in the western tropical Pacific warm pool.
“Not all El Niño events are accompanied by this unusual wind pattern” notes Malte Stuecker, “but once El Niño conditions reach a certain threshold amplitude during the right time of the year, it is like a jack-in-the-box whose lid pops open.”
A study of the evolution of the anomalous wind pattern in the model reveals a rhythm of about 15 months accompanying strong El Niño events, which is considerably faster than the three- to five-year timetable for El Niño events, but slower than the annual cycle.
“This type of variability is known in physics as a combination tone,” says Fei-Fei Jin, professor of Meteorology and co-author of the study. Combination tones have been known for more than three centuries. They where discovered by violin builder Tartini, who realized that our ear can create a third tone, even though only two tones are played on a violin.
“The unusual wind pattern straddling the equator during an El Niño is such a combination tone between El Niño events and the seasonal march of the sun across the equator” says co-author Axel Timmermann, climate scientist at the International Pacific Research Center and professor at the Department of Oceanography, University of Hawai’i. He adds, “It turns out that many climate models have difficulties creating the correct combination tone, which is likely to impact their ability to simulate and predict El Niño events and their global impacts.”
The scientists are convinced that a better representation of the 15-month tropical Pacific wind pattern in climate models will improve El Niño forecasts. Moreover, they say the latest climate model projections suggest that El Niño events will be accompanied more often by this combination tone wind pattern, which will also change the characteristics of future El Niño rainfall patterns.
Citation: Stuecker, M. F., A. Timmermann, F.-F. Jin, S. McGregor, and H.-L. Ren (2013), A combination mode of the annual cycle and the El Niño/Southern Oscillation, Nature Geoscience, May 26 online publication at http://dx.doi.org/10.1038/ngeo1826.
h/t to Dr. Leif Svalgaard
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I would like to spout about the “quasi-biennial oscillation”.
(Oscillation of easterly/westerly wind around the tropopause,
in the tropics especially in or near the ITCZ, and maybe
more in the Western Hemisphere.)
This is a known atmospheric phenomenon, with half-period
being typically a little over a year. Full period is a little over
2 years, maybe usually 2.5 years.
I have seen some correlation between QBO and ENSO.
I have seen El Ninos to be disproportionately occuring
when QBO is westerly (from west to east).
And when the east-equatorial Pacific is “no baby”,
especially with also QBO being westerly, I see America
getting fewer but more-notable windy storms.
Ric “If your backyard floods in a seiche or a NYC subway tunnel floods in a storm surge, most people’s primary concern is not how the water lifted and moved in, but that it did. From the point of view of whoever is flooded, water piled up.”
.. and storm surges are causes by ?
Not a surface wind making the water pile up and at one end but due to the atmospheric depression of the storm. Which is [precisely what I said :
“If mean sea level is higher it must is more to do with the depression on one side and the high on the other that is driving the wind in the first place. Otherwise it would just flow north and south from the west Pacific and circulate.”
Please try to read and understand before commenting.
Ian Wilson says:
Greg Goodman – regarding the split peaks – very good observation!
http://climategrog.wordpress.com/?attachment_id=279
I think that what you are trying to point out is that there are frequency peaks at 1.59 years and 4.43 years that are amplitude modulated by a higher frequency phenomenon present in the data.
===
Thank you. I’m glad there’s someone who can follow what I’m doing.
I’ve just had a look at the trade wind index:
ftp://ftp.cpc.ncep.noaa.gov/wd52dg/data/indices/wpac850
It is showing very similar values but without some of the doublets. There are still major peaks around 3 an5 that produce 4.434 year central value.
Be careful not to be too liberal “seems close to” attributions. A 18 month peak from a 32 year dataset has to be pretty close. Bending it to fit 19 months getting very shaky.
The 8.85 year lunar cycle looks like a definite hit
I’ll give more details on how I derived the spectra later once I’ve checked results.
Greg Goodman (May 27, 2013 at 7:02 am) wrote:
“[…] My gut feeling is that it’s ocean currents driving winds rather than the opposite. […]”
I hope you’re not serious.
http://dx.doi.org/10.1038/ngeo1826
Seems the link has been scuppered by Nature. I still have the page open from yesterday but it no longer works.
They must have realised they’ve published something that can lead to juniper.
Greg, you should also take a look at some SSH (sea surface height) data.
Greg Goodman says:
May 27, 2013 at 2:06 pm
Nino3.4 data has clearly been “smoothed”,
—————————-
Nino 3.4 has been smoothed in a 3 month moving average in some datasets but this value is almost exactly the same as the straight single month number. I mean you could not see the difference. It is just the way the ENSO builds up/declines and draws down/warms back up over time.
So the newer datasets have just discarded the smoothing since it makes no difference.
————
On the Trade Wind index, the whole Pacific going from 135E to 95W provides the best correlation, although sometimes the Western Pacific Trades leads Nino 3.4 by a month or two but it is not consistent enough to be reliable.
http://s16.postimg.org/uffs9j351/West_Pac_Trades_ENSO_Apr_2013.png
Bill, thanks for your comment. I was forgetting that averaging inherent in the index. I just ignore “indices” created like that and go for the SST directly. Sadly running means are ubiquitous in climate science, there is even one at the heart of the Hadley climatology creation algo against which their ‘anomalies’ are derived. Worse , they put it in an iterative loop until it “converges”. I suspect that is one of the main causes for the differences I find in the spectra of ICOADS and hadSST3.
They also manage to crate some strange teleconnections that aren’t in the original data. Very odd.
Paul Vaughan says: Greg, you should also take a look at some SSH (sea surface height) data.
Could you be more specific?
Based on NUSJMaEV:
(22.2)*(6.4) / (22.2 – 6.4) = 9
(11.1)*(3.2) / (11.1 – 3.2) = 4.5
(22.2)*(9) / (22.2 + 9) = 6.4
(11.1)*(4.5) / (11.1 + 4.5) = 3.2
(6.4)*(1) / (6.4 – 1) = 1.185
(12.8)*(2) / (12.8 – 2) = 2.37
The framework is found in heliospheric, lunisolar, & climate series.
Well-constrained climate series (laws of large numbers & conservation of angular momentum) that reverse phase with heliospheric series suggest resonance on the lunisolar framework (rather than a lunisolar driver).
Dickey, J.O.; & Keppenne, C.L. (1997). Interannual length-of-day variations and the ENSO phenomenon: insights via singular spectral analysis.
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/22759/1/97-1286.pdf
Greg Goodman (May 28, 2013 at 6:11 am) asked
“Could you be more specific?”
censorship 1/2/3…
Jean Dickey (NASA JPL) emphasizes that mass, temperature, & velocity are coupled. There’s an excellent ENSO video that will help you see the SSH (mass) coherence with temperature & velocity (wind). It overlays wind vectors on color-coded-SST & SSH (radial axis elevations). Bob Tisdale might have the link. The video makes the coupling & spatiotemporal coherence crystal clear. Bill Illis might be able to link to related graphs.
Dickey, J.O.; Marcus, S.L.; & Chin, T.M. (2007). Thermal wind forcing & atmospheric angular momentum: Origin of the Earth’s delayed response to ENSO. Geophysical Research Letters 34, 7.
http://adsabs.harvard.edu/abs/2007GeoRL..3417803D
“[…] thermal winds arising from the poleward gradient of tropical temperature (TT). We show that the TT gradient (TTG), which peaks 1-2 months after the Nino 3.4 SST anomaly, is the source of the thermal winds that drive […]”
Dickey, J.O.; Marcus, S.L.; & de Viron, O. (2003). Coherent interannual & decadal variations in the atmosphere-ocean system. Geophysical Research Letters 30(11), 1573.
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/11255/1/02-3203.pdf
http://technology.jpl.nasa.gov/people/j_dickey/
Here is something new.
The Pacific Trade Wind Variability. Normally, the winds at the equator are blowing east to west. This is dragging the surface waters along with it and generally the ocean currents in the equatorial Pacific are flowing east to west driven by the wind and manner in which a rotating planet organizes its atmosphere and ocean.
In an El Nino, these winds slacken and can even blow the other direction, west to east, in which the warm waters from the western warm pool will move back into the eastern side (dragged backwards in essence and also by gravity since the western side is metres higher than the eastern side of the Pacific). These western waters can be 2.5C to 3.0C warmer than the central and eastern Pacific, and, hence, there is an El Nino when this occurs.
But it is really the Western Pacific Trade Winds which have the variability. The central and eastern parts do not really. In December, in particular, the Western Trades are 6.0 metres per second to the West or 6.0 metres per second to the East. The central and eastern sides are still generally to the west. Ie. The Western Pacific Trade Winds are really the driver.
A busy chart that might be hard to understand fully, but the above is what it shows. Something like what this paper might be about.
http://s18.postimg.org/9grc3c8zd/Pacific_Trade_Wind_Variability_Apr_2013.png
This chart might be more clear.
http://s12.postimg.org/r23to2v6l/West_East_Pacific_Trade_Wind_Variability_Apr_201.png
Affects aviation:
http://img829.imageshack.us/img829/2836/volcano911.png
http://img268.imageshack.us/img268/8272/sjev911.png
There are defense implications.
Greg, here’s the video …
Visualizing El Nino From NASA Scientific Visualization Studio
h/t Bob Tisdale:
http://wattsupwiththat.com/2013/04/14/a-different-perspective-of-the-equatorial-pacific-and-enso-events/#comment-1275613
Greg Goodman: Seems the link has been scuppered by Nature.
It worked for me.
thanks, I like the 3D presentation of the data, a very effective way to capture several variables at once. Shame the dataset isn’t a bit longer. It does not really last longer enough to get an idea of how it evolves.
I’ve also seen a similar simulation of the thermocline which only re-enforced my impression of a long term tidal phenomenon.
I think I once calculated that the density difference was about 3000 time smaller than air/water barrier. That means the equivalent of a 12h surface tide would be about 4 year tide in the thermocline. In view of the present discussion that is bang on. The surface resonates with the daily passage under the moon, the thermocline response time dictates it will react to something like the 8.85 year lunar cycle.
Having already noted that 4.43 is exactly half of a lunar periodicity and knowing the prime mover of surface tides is the moon …… join the dots.
Thanks for all the other papers.
So all this has been known, studied in painstaking detail and published for at least two decades and were a still told ENSO is some unfathomable, un-modelable mystery. That paper even says it can provoke decadal scale warming, something Bob has been trying to draw attention to.
[Bob, maybe you can now see what I meant last year about your having found the mechanism , not the cause and that the need to look for the cause of what was driving El Nino. You took it the wrong way , but this is what I was trying to point to.]
FWIW , if ENSO is lunar in origin then much of the other variation in other regions may be common causation, not a direct influence of El Nino. That may help to explain the surprisingly wide supposed impact of this relatively obscure part of the Earth’s surface.
Matthew , all I get is some big print:
nature.com homepage
Publications A-Z index
Browse by subject
maybe they’ve blocked my IP ???
Sustained north winds routinely pile up water a foot high at the south end of the GSL:
terdata.usgs.gov/ut/nwis/uv/?site_no=10010000&PARAmeter_cd=00065,00060,00010,72020
http://www.weatherhq.com/weather-station/salt-lake-city-international–airport
…and otherwise move water around big puddles.
None of the astrologers has invoked the 433 day Chandler Wobble period. Good.
The ear doesn’t create beat frequencies; it detects them. Proof: take two tuning forks, one at A440 and another at A419. Hold both near one ear: beat detected. Hold them near opposite ears: none. –AGF
http://waterdata.usgs.gov/ut/nwis/uv/?site_no=10010000&PARAmeter_cd=00065,00060,00010,72020
That link got chopped. –AGF
Paul, the question I wanted to ask you about your comment and wavelet plots in your comment at TS was the following and is relevant here: if there is a pervasive circa 9y cycle in physical record but there is also one or more related frequencies that are at times in anti-phase with it and neutralise it, it will still be detected in a sample long enough to identify them both. However a short period wavelet analysis is specifically designed to take a narraw view and will not detect a signal which is temporarily absent due to anti-correlation with another signal.
why did you conclude that 9y period was not permanently present on the grounds of a short term wavelet waterfall that would not show its presence in such circumstances?
For example the Arctic plot has a very strong , multiple circa 2y components yet if you do a narrow wavelet analysis , between 1986 and 1990 it will tell you there is noting in that range: That does not mean it is not there , it is just destructive interference.
http://climategrog.wordpress.com/?attachment_id=216
440 – 1 = 439. A439.
PDS of trade winds: from chirp analysis of autocorrelation fn:
http://climategrog.wordpress.com/?attachment_id=281
1.827a = 22m
2.455a = 29.5m
4.431a = 53m
Greg: Goodman said:
Having already noted that 4.43 is exactly half of a lunar periodicity and knowing the prime mover of surface tides is the moon …… join the dots.
[Bob, maybe you can now see what I meant last year about your having found the mechanism , not the cause and that the need to look for the cause of what was driving El Nino. You took it the wrong way , but this is what I was trying to point to.]
AND
FWIW , if ENSO is lunar in origin then much of the other variation in other regions may be common causation, not a direct influence of El Nino. That may help to explain the surprisingly wide supposed impact of this relatively obscure part of the Earth’s surface.
MY COMMENT:
This is what I have trying to tell Bob and others for years, however, most [not you Greg] have politely either ignored my comments or dismissed my research papers and work. I have tried to pointing people to the work of others [e.g. Claire Perigaud] that support a Lunar tidal explanation for the ENSO phenomenon but this has failed to produce any interest.
Thank you Greg for your support of the Lunar Tidal explanation!
If you are still interested, please read:
Long-Term Lunar Atmospheric Tides in the Southern Hemisphere
Ian R. G. Wilson and Nikolay S. Sidorenkov
The Open Atmospheric Science Journal, 2013, 7, 29-54
http://www.benthamscience.com/open/toascj/articles/V007/TOASCJ130415001.pdf
Greg: Goodman said:
Having already noted that 4.43 is exactly half of a lunar periodicity and knowing the prime mover of surface tides is the moon …… join the dots.
[Bob, maybe you can now see what I meant last year about your having found the mechanism , not the cause and that the need to look for the cause of what was driving El Nino. You took it the wrong way , but this is what I was trying to point to.]
AND
FWIW , if ENSO is lunar in origin then much of the other variation in other regions may be common causation, not a direct influence of El Nino. That may help to explain the surprisingly wide supposed impact of this relatively obscure part of the Earth’s surface.
MY COMMENT:
This is what I have trying to tell Bob and others for years, however, most [not you Greg] have politely either ignored my comments or dismissed my research papers and work. I have tried to pointing people to the work of others [e.g. Claire Perigaud] that support a Lunar tidal explanation for the ENSO phenomenon but this has failed to produce any interest.
Thank you Greg for your support of the Lunar Tidal explanation!
If you are still interested, please read:
Long-Term Lunar Atmospheric Tides in the Southern Hemisphere
Ian R. G. Wilson and Nikolay S. Sidorenkov
The Open Atmospheric Science Journal, 2013, 7, 29-54