A new paper in Geophysical Research Letters was brought to my attention by Dr. Leif Svalgaard.
Tropical origins of North and South Pacific decadal variability by Jeremy D. Shakun and Jeffrey Shaman makes some very interesting findings suggesting that both the northern and southern Pacific Ocean has evidence of the Pacific Decadal Variation PDV being driven by ENSO variations. They produced a model, which when run correlates reasonably well with observations.
Abstract:
The origin of the Pacific Decadal Oscillation (PDO), the leading mode of sea surface temperature variability for the North Pacific, is a matter of considerable debate. One paradigm views the PDO as an independent mode centered in the North Pacific, while another regards it as a largely reddened response to El Nin˜o-Southern Oscillation (ENSO) forcing from the tropics. We calculate the Southern Hemisphere equivalent of the PDO index based on the leading mode of sea surface temperature variability for the South Pacific and find that it adequately explains the spatial structure of the PDO in the North Pacific. A first-order autoregressive model forced by ENSO is used to reproduce the observed PDO indices in the North and South Pacific. These results highlight the strong similarity in Pacific decadal variability on either side of the equator and suggest it may best be viewed as a reddened response to ENSO.
They write about the graph above:
…we model PDV as a first-order autoregressive process driven by ENSO as done by Newman et al. [2003]. This AR-1 model is applied to the North and South Pacific separately.
The modeled PDO index at year n is a function of the modeled PDO index at n – 1 and the observed ENSO index (Nino 3.4) at n. These annually-averaged indices are centered on boreal winter (Jul–Jun) for the North Pacific and austral winter (Jan–Dec) for the South Pacific. Per Newman et al. [2003], the coefficients β and α are parameters derived, respectively, by regression of the PDO index on the ENSO index, then autoregression of the residual time series with a lag of one year. h is an uncorrelated noise term not used in our analysis but shown for completeness. a and b are 0.51 and 0.56 for North Pacific PC1 and 0.62 and 0.71 for South Pacific PC1. While Newman et al. [2003] found this simple model did a remarkable job reproducing the observed 20th century PDO index in the North Pacific (r = 0.63 in our study), it yields an even stronger fit to our Southern Hemisphere PDO index (r = 0.71) (Figure 4).
The greater success of the model in the South Pacific may be a function of its larger α and β terms, which indicate that the persistence of SST anomalies and ENSO forcing are more important. The stronger ENSO signal in the South Pacific may derive from the equatorial asymmetry of ENSO SST anomalies in the eastern tropical Pacific, which extend considerably farther to the south than to the north. One implication of this finding is that the South Pacific may be a better place to develop paleo-ENSO records as it appears to contain a ‘cleaner’ ENSO signal.
Conclusion
Deriving a Southern Hemisphere equivalent of the PDO index shows that the spatial signature of the PDO can be well explained by the leading mode of SST variability for the South Pacific. Thus, PDV appears to be a basin-wide phenomenon most likely driven from the tropics. Moreover, while it was already known PDV north of the equator could be adequately modeled as a reddened response to ENSO, our results indicate this is true to an even greater extent in the South Pacific.
Leif has a copy of the paper on his website that you can read here
Citation:
Shakun, J. D., and J. Shaman (2009), Tropical origins of North and South Pacific decadal variability, Geophys. Res. Lett., 36, L19711, doi:10.1029/2009GL040313.
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Thanks for the interesting paper … as a casual observer, it is indeed complex but it seems to reaffirm that “it is the sun stupid” and, of course, the oceans.
(May have mentioned this previously… it is my little way of feeling insignificant RE: GW.)
There are ~ 250,000,000 tonnes of ocean water for every person on earth. (The math is ~ correct.)
I just can’t see a family of four in their suburban bungalow; SUV and compact car; their jobs at the factory and school; all of their trappings having any affect whatsoever on ocean temps (on “their” one billion tonnes of water) compared to the sun beating down (or not) on the oceans somewhere on earth 24/7.
“Warmers” apparently think we are relatively important. We are nothing.
Clive
In the not-quite-so-frozen-North … not like last week anyway ☺
I am always bemused by these ocean discussions, particularly as they never mention/model the tides.
Twice a day a big bulge of energy travels around the globe and moves waters from the bottom up . It moves the land too , but that is another story.
Is it possible that this motion plays no role in distributing the heat of the ocean? It cannot all be vertical, from conservation of angular momentum.Even the vertical disturbance will mix cold and hot waters to some extent.
Considering also that there are high tides and low tides and “some other name” tides due to the variable orbit of the moon about the earth, I could easily see time modulations due to that.
Does anybody know ( have a link) whether tideshave been modeled/calculated or whether they are ignored because the effect is much smaller that the other drivers of ocean currents?
@ur momisugly GP:
-From the report:
–
-“These annually-averaged indices are centered on boreal winter (Jul–Jun) for the North Pacific and austral winter (Jan–Dec) for the South Pacific.”
–
-Is that correct for ‘winter’? It seems counter intuitive.
No, the statement is correct. Notice, the indicies are *centered* on the repective winters which means the time spans need to start/end in the respective summers so the winter times would be in the center of the timespan.
Jeff
I really wish that all these climate modelers would come up with a model that works from first principles, not just by twiddling with recorded data. Take a look at the work Einstein did on the phote-electric effect. He figured out what had to be at the basis of the effect and worked out a simple equation that has withstood the test of time, and had significant implications that were proved true well after he developed the equation.
When the climate modelers can show me a set of equations of similar insight and economy that do not depend of “parameters” elicited from previous data I might believe them. Then, when they can take the climate data from any historic period, show that the model accurately predicts the data from the starting conditions, and works throughout the data set, then they will have a model that MAY usefully predict future climate trends.
The model used in this discussion is an empirical model, based on parameters derived from the historical data. One of the first things I learned in statistics is that an empirical model only works within in the data range used to develop the parameters. So, the fact that the model and data diverge at some point IS TO BE EXPECTED. It is simple curve fitting, which can tell us something about the trends and variation in the data, but says absolutely nothing about the underlying physics or mechanisms.
As the inimitable Yogi Berra said, “making predictions is very tough, especially about the future”. I like to add my own corollary, ” it’s even harder when you want the right answer”.
As a weather observer in Colorado Springs in the late 80’s, I witnessed an Aurora one early morning (first observation had to be done at 3:55 am). Was it possible that I witnessed the beginning of the 90’s global warming that has caused so much concern with our society?
The cold dark deep of the oceans is not aware of your tides, Anna. What are they? They are a constant redistribution of the ocean’s superficial layers, with minimal heat redistribution. A high tide only occurs on a full moon. ( to the sun the moon is always full except when the Earth gets in the way)
Tsunamis on the other hand involve deeper disturbances in the ocean’s energy. Tsunamis are caused by anthropogenic global warming.
Slightly O/T:
I wonder if we’ve reached some kind of tipping point where we get an avalanche of major media stories doubting AWG. This morning there is an opinion piece in the Globe and Mail by Rex Murphy. Rex’s opinion is that the leader of the Liberal party (Michael Ignatief) should not tie himself to the AWG bandwagon. We’ll see if Ignatief takes the advice or not but it is reasonably certain that he (scholar that he is) will give it due consideration.
The thing that I find heartening is that Rex (love him or hate him or both at the same time) is writing in ‘Canada’s National Newspaper’ and, in a sense, what we are hearing is the voice of the establishment.
http://www.theglobeandmail.com/news/opinions/michael-ignatieff-should-think-outside-the-green-box/article1327161/
Stream of Conscience: Not Evil Just Wrong to Stream Live, for Free, Over Internet This Sunday
http://www.reuters.com/article/pressRelease/idUS172412+16-Oct-2009+PRN20091016
Superfreakonomics: Global Cooling, Patriotic Prostitutes and Why Suicide Bombers Should Buy Life Insurance
http://www.ft.com/cms/s/2/1c1d0386-b9e4-11de-a747-00144feab49a.html
Clive:
The “tonnes of ocean water per person” ratio creates a mental picture that we should all pass along to those we know who are just now beginning to wonder about AGW. Many people didn’t learn much about chemistry or physics in high school, and don’t feel capable of making up their own mind on this issue because it seems so “academic” or “scientific” to them. But those same people still have common sense, and can picture themselves standing beside a giant pool of sea water, ten feet deep and 5.25 miles on each side, wondering what they could do to raise its temperature. (Somebody check my numbers, please.)
Could you supply a link to your source for the 250,000,000 tonnes per person statistic?
tokyoboy (00:19:01) :
Most of the heat on the earth’s surface comes from the sun, and its intensity has been almost constant in these 100 plus years (except for a 0.1%-level fluctuation during a solar cycle).
In view of this, I now suspect, as a chemist not familiar enough with this field, that PDO, PDV, AMO etc. are caused by periodic changes of heat partitioning between the surface and underneath of the ocean, and this in turn is caused by the periodic pattern change of ocean currents (and ultimately by the periodic pattern change in the wind?).
Correct me please if such a speculation is wrong.
Sure. Even a perfectly constant (big) sun can initiate and sustain many oscillations her on (small) earth. This is for example equivalent to the reaction–diffusion systems that display a wide range of oscillatory behaviors, including the formation of traveling waves and wave-like phenomena as well as other self-organized patterns like stripes, hexagons or more intricate structure like dissipative solitons.
http://en.wikipedia.org/wiki/Reaction–diffusion_system
Possibly the nonlinear oscillations here on earth may be present on many time scales, from days, to years and centuries.
The following link presents information on the formation of El Nino and La Nina, including several theories regarding the cause.
http://www.crystalinks.com/elnino.html
“Thanks for the interesting paper … as a casual observer, it is indeed complex but it seems to reaffirm that “it is the sun stupid” and, of course, the oceans.
(May have mentioned this previously… it is my little way of feeling insignificant RE: GW.)
There are ~ 250,000,000 tonnes of ocean water for every person on earth. (The math is ~ correct.) ”
Thanks Clive,
That puts everything in perspective.
“… These results highlight the strong similarity in Pacific decadal variability on either side of the equator and suggest it may best be viewed as a reddened response to ENSO.
…”
Pardon my red face but, in the context of the paper, what does reddened mean? [Possibly warmer?]
PIONEERING METEOROLOGIST
Robert Fitzroy, Darwin’s captain on the Beagle, was a pioneering meteorologist.
Voyages contained detailed observations of weather conditions, on the basis of which Fitzroy was appointed to the Board of Trade in 1854 to set up “uniform meteorological observations at sea”. Royal Navy and merchant ships were asked to submit data for a general weather survey.
Fitzroy’s survey was a huge success. Initially its purpose was purely to record the weather, but he came to see that by collecting and collating data systematically over a wide area it should be possible to predict — or forecast — future weather.
http://www.timesonline.co.uk/tol/news/science/eureka/article6866634.ece
The first attempt at a general weather forecast in The Times came on July 26, 1877.
http://archive.timesonline.co.uk/tol/viewArticle.arc?articleId=ARCHIVE-The_Times-1877-07-26-10-003&pageId=ARCHIVE-The_Times-1877-07-26-10
What is the need of one more model if real causes are not all included, except if “conveniently adapted” to current and fleeting reality. In any moment, some unexpected (for the gamers not for true observers) and not modelled phenomena will for sure appear. This is the case of all solar models and all solar cycle forecasts based on imaginative, but not necessarily based on reality, theories.
We humans have long had a rather inflated view of our importance in the grand scheme of things. The AGW movement is in my opinion just another manifestation of this phenomenon.
I suspect my views are biased from the science education I received before the advent of modern “critical thinking” in our academic system. And also perhaps from the experience I gained working in remote regions during my youth, where the scale of man is manifestly evident. My error also might have been to see computers as tools rather than instruments of revealed truth.
Perhaps I will eventually reform and adopt the “critical thinking” ways of my betters, but in the mean time I am content to be a skeptic and think my “uncritical” thoughts.
Kate (03:25:44) :
An item appeared about this today in The Telegraph
Where Geoffrey Lean asserts that:
“Almost all climatologists expect warming to continue in the long term, but – because of natural fluctuations – they disagree about the immediate future….
You may wish to comment on that statement in the box provided on his page.
Not only comments in The Telegraph from our learned WUWT crew — but is it time for another post on the physics of CO2 that makes this long-term fright of frying fridiculous? Is there new information on the behavior of CO2 in the atmosphere that should be included?
reddened
I understand it to mean made more red or resulting from inflammation. I assume the usage is basically jargon for a response driven by something, or inflamed by it.
Yes?
OK, here is a link for currents and tides:
http://www.aviso.oceanobs.com/en/applications/ocean/tides/tides-and-climate/index.html
“Ocean waters are stratified according to their density. The different layers mix with difficulty. However the tidal currents coming into contact with the relief of the ocean bottom (even if this is very deep) creates waves which are propagated at the interface between two layers of different densities. It is currently thought that this mechanism contributes more than half of the vertical mixing of water masses. Now this mixing is fundamental for large-scale ocean circulation (thermohaline circulation) which enables the redistribution of heat from the equator to the poles.”
Thank you for that, it is a great piece.
As for secular humanism, it is odd to think that it would grow into a new religion, but there’s a couple more ingredients, I gather.
Postmodernism ended up combining an egalitarian cognition with a narcissistic ego. People became aware of the world, and needed that they individually be the ones who saved it. This is the source of “we’ve got to do something!” (See, we really need to, our egos depend on it.)
I’m not trying to be scathing, I feel I went through this view about 20 years ago, but passed through it because I later became exposed to other ideas.
Cognitively there are several tricks used to get round the usual practical and rational objections to such a project.
The Precautionary Principle sidesteps the scientific method of falsifiability, whilst claiming to remain scientific.
Multiculturalism is used to affirm that no one culture is better than any other, whilst kicking in the teeth Western culture of consumerism and big business, and promoting multiculturalism as the best culture.
Having said that, there are thinkers who are looking at environmental issues in a more sophisticated way, but they’re the minority for now.
And another connecting the dots:
http://ocean.mit.edu/~cwunsch/papersonline/wunsch_2000_moon_climate_nature.pdf
“for such a source: winds and tides.
For over 75 years13,14 it was thought that
the tides dissipated almost entirely by friction
in the shallow seas above the continental
shelves. But Munk and I concluded3 that
about half of the power required to return
the deep waters to the surface was coming
from mixing driven primarily by dissipation
of tidal energy — principally lunar, but with
a minor solar component — in the deep
ocean (Fig. 1). Now, by fitting a dynamical
model to satellite altimetric measurements
of the tides, Egbert and Ray2 have produced
an observational estimate of 1 terawatt of
open-ocean tidal dissipation. Their numbers
are not definitive, but they are in agreement
with the energy values required by the deep
upwelling, and with the total — shallow
(about 2 terawatts) plus deep — energy
losses implied by the lunar recession.”
Kate:
Nope, not really. Written by a environmentalist journalist, and just one or 2 quotes. Not heavy on the proof. GISS temperature records are poor…station siting is poor…4000 stations, mostly rural, stopped reporting in the 90’s. There wasn’t 50% coverage of the southern hemisphere until 1940. “Homogenization” of the data is questionable. Marysville station (urban setting) has no UHI adjustment in 2009, but in 1880 there is a -2c adjustment. Nice case of cool the past to make the present warmer. Satellite records are better, but essentially start at the end of a cool phase of the PDO, so I don’t think a good trend will be seen until the end of the next cool phase..in maybe 20-30 years. The only “hockey” stick type warming seen is proxy studies….see Steve McIntyre’s analysis of that. I think most skeptics will agree that since the mid 1800’s it’s gotten warmer (which of course was the end of the little ice age).
Stefan (12:04:29) :
Thank you for that, it is a great piece.
Apparently the moderator didn’t think so as my post here and on a couple of other threads have been deleted (not even “snipped”).
I thought it was an important essay in the AGW debate.
reddened
I understand it to mean made more red or resulting from inflammation. I assume the usage is basically jargon for a response driven by something, or inflamed by it.
What happens to some when you bring up Piers Corbyn.