Guest Post by Willis Eschenbach
On another thread, a poster got me thinking about the common practice of using the El Nino 3.4 Index to remove some of the variability from the historical global average surface temperature record. The theory, as I have heard it propounded, is that the temperature of the Earth is “signal”, whereas the El Nino cycles are natural swings and as such are just “noise”. So if you remove the El Nino swings from the temperature, the theory goes, then we can see more of the underlying temperature signal by removing the noise.
Figure 1. Various “Nino regions” used in the study of the El Nino / La Nina phenomenon. Each area has its own index, with one of the most commonly used being the Nino 3.4 Index. SOURCE. See also the NOAA page
The more I thought about the practice of subtracting the Nino 3.4 variations from the global average temperature anomalies, the more questions came up for me. I don’t have the answers, hence this post. The first question that came up is, how do we decide that the Nino 3.4 Index represents noise instead of signal?
The Nino 3.4 region covers about 2.4% of the planet’s surface, a bit bigger than the USA. So … why isn’t the temperature of the USA “noise”? Or perhaps, is the temperature of the US “noise” but no one ever checked? And how would you check? What mathematical procedure would allow us to discriminate? What test would we use to say well, Nino 3.4 is noise so we can safely subtract its effects from the global temperature signal, but, for example Nino 1+2 is not noise, it’s part of the signal?
My next question about the situation revolves around the fact that the Nino 3.4 Index is merely a linear transform of the sea surface temperature of the Nino 3.4 area. So what we are doing is taking a linear transformation of the surface temperature anomaly in one part of the world, and subtracting it from the global average surface temperature anomaly.
As a result the question is, is this a legitimate operation? Subtracting a linear transform of something from the whole of which it is a part? Like, say, taking the average temperature variations in the whole US including Texas, but then subtracting out some linear transform of the temperature variation in Texas? What is the meaning of that procedure, subtracting something from itself? And if we are going to subtract a transform of say the Nino 3.4 temperature from the global average, should we include the Nino 3.4 temperature to begin with when we calculate the global average, or not?
Next question is, is this a legitimate operation in a system with a thermostat? Like for example, taking the variations in my body temperature, but subtracting out some linear transform of the temperature variations in my foot? What does that procedure give us, what does the result mean?
Next question. If we’re going to remove the transform of the El Nino Index from the global average temperature record, then should we remove the other indices as well? Should we remove the AMO (Atlantic Multidecadal Oscillation) Index? The PDO (Pacific Decadal Oscillation) Index? The Madden-Julian Oscillation Index? Some combination of them? All of them?
Final question. From my perspective, the El Nino/La Nina oscillation actively regulates heat loss, and thus is part of the planetary temperature regulation system. It regulates the heat loss by way of both the ocean and the atmosphere. Let me give a functional explanation of how it works. The explanation is slightly but not significantly simplified.
During La Nina conditions, in the upper part of Figure 2 below, the warm blanket of water normally covering the Pacific has been blown to the west by the strong eastern trade winds. From there, that mass of warm Pacific surface water splits and moves north and south along the coasts of Asia and Australia towards the Poles. The mass of water is radiating and losing heat as it travels. Functionally, the El Nino/La Nina alteration serves as a huge, slow-cycling, thermally regulated Pacific-wide pump. The La Nina pump stroke moves warm Pacific surface water poleward to lose its heat through conduction, radiation, and evaporation.
Figure 2. La Nina and El Nino conditions. North and South America are the brown areas in the upper right. Australia is at the lower left. Black arrows in the atmosphere show the direction of atmospheric circulation. White arrows show surface ocean currents SOURCE: NOAA El Nino Theme Page
In addition to moving warm Pacific water poleward, the removal of the warm Pacific tropical surface waters exposes the atmosphere to huge amounts of cooler sub-surface Pacific water. This lowers the air temperature over that whole area of the tropical Pacific. Soon, however, the surface of the Pacific starts to warm again. One effect of this is that it slows down the eastern trade winds. As a result of reduced winds and reduced clouds, the warming of the surface of the Pacific continues. In addition, some of the warm surface water in the Western Pacific moves back out east. Soon, with the sun beating down on an ocean with reduced clouds, it warms up all across the Eastern Pacific. This leads to neutral conditions, which can last a while.
However, if the tropical Pacific surface temperature warms enough, then El Nino conditions develop. After the El Nino conditions come into being, at some point as the surface of the Pacific continues to warm, and the El Nino thunderstorms drive the surface air upwards, the eastern trade winds start to strengthen. Soon the eastern trade winds start pushing the warm tropical surface waters and their associated thunderstorms and clouds to the west across the Pacific and eventually poleward again. This is the power stroke of the pump, when the trade winds strip the warm surface waters off and push them westwards. In this process, the full La Nina conditions come into existence. Finally, the La Nina conditions eventually peter out to a neutral condition once again.
Note that this system is triggered by temperature. If the temperature doesn’t build up across the surface of the eastern Pacific for some reason, then things stay neutral, neither El Nino or La Nina. In that case, the El Nino doesn’t form, and so the eastern trade winds don’t build up to pump the warm water across the Pacific and towards the poles.
But when the surface waters of the Pacific do heat up beyond a certain point, El Nino conditions arise, the eastern trade winds strengthen and pump the warm tropical surface water, first across the Pacific and then to the poles. It also exposes the atmosphere to a large area of cooler subsurface water.
Note the effect of this amazing temperature regulating heat pump. It functions to prevent any long-term buildup of heat in the waters of the surface Pacific. If the water in the surface of the Pacific stays cooler, the heat pump doesn’t kick in. But as soon as a certain amount of heat builds up in the surface Pacific waters, the El Nino/La Nina alteration occurs, pumping the surface water west to be flushed out toward the poles. The layer of warm surface water that was blown west is then replaced by cooler water from the subsurface, cooling the entire tropical Pacific.
This mechanism, this El Nino/La Nina pump skimming off the hot Pacific water and pumping it to the poles, prevents long-term Pacific heat buildup and thus actively keeps the planet from both overheating and excessive cooling. It is one of the many interacting thermoregulating mechanisms that keep the earth from either overheating or becoming too cool.
So … this brings up the final question regarding the theme of this post.
Since the variations in the Nino 3.4 index are indicative of the functioning of one of the Earth’s major thermoregulating mechanisms, namely the giant El Nino/La Nina pump that magically materializes to move warm tropical Pacific water to the poles whenever the planet gets too hot and sweaty … then under what possible construction could the Nino 3.4 Index variations be called “noise”?
Like I said … lots of questions, I don’t have the answers, all courteous contributions welcomed.
Regards to all,
w.
philr1992 says:
January 17, 2013 at 7:55 am
Thanks, Phil. First, as I specified, I was giving a functional explanation of the El Nino/La Nina swing. It functions as a way for the Pacific to lose huge quantities of energy fast when surface waters get over a certain temperature. It does that by pumping warm water from the surface Pacific to the poles and replacing it with cooler subsurface water.
As I also said, I was going to simplify the process, but that for the purpose of discussing how the El Nino/La Nina swing works to regulate the planetary temperature the simplifications would not be significant. I still hold that that statement is true.
Now, as you point out, there are a host of related phenomena. Annular modes, the stress fields, wind fields, standing gyres, the QBO, the list is long. Heck, there’s even bizarre waves involved that go from the Asian side of the Pacific to the South American side, where the wave is reflected and morphs into another kind of wave to make the return journey to Asia. How strange is that? And how many climate models capture that? But I digress …
So as you correctly state, there’s lots of other stuff involved. I wasn’t interested in any of that, because basically I was describing how the ENSO works to regulate planetary temperature. When the whole of the tropical Pacific gets hot, you get El Nino conditions. These then increase the eastern trades and resulting surface currents, driving the warm surface water west and polewards, and in the process creating La Nina conditions. However, as you point out there are many other phenomena and measurable variables involved in the whole process of pumping the heat to the poles.
Thanks for pointing that out,
w.
Treating ENSO as noise is ludicrous. ENSO has profound effects on climate. It seems to me that the idea of treating ENSO as noise is just more of the garbage science that you get from the global warmers whose never ending wet dream is to “fix” the data.
rgbatduke- exactly I feel there is an element of racism involved also,in the lack of equality in Development. Greenies fear healthy, happy, prosperous , dark skinned people.
(Their son or daughter might marry one..) . I’m all three races,BTW…
Sounds like the Nino 3.4 area is a bit like a thermostat. If you remove the thermostat from the equation when the Summer months begin to warm, Your AC doesn’t turn on and you get warmer. If you remove the Nino 3.4 area from the equation, the signal also reads warmer than it really is
Leron says: My question is, when there is a strong El-Nino whay does the earths atmosphere heat up? is it because the El-Nino pumps more water vapor into the atmosphere enhancing the greenhouse effect, or does the heat get transfered to the atmosphere from the oceans surface through convection and conduction. Or perhaps both.”
During an El Nino, more warm water than normal covers the central and eastern tropical Pacific. That causes more water to be evaporated from the surface. The moist warm air rises, and as it rises, it cools. Eventually, it cools to the point that it can no longer hold the moisture, so that moisture condenses and forms rain. As it turns to rain, it releases the heat from the sun that warmed the water in the first place.
You’ll find a similar description at NOAA FAQ webpage here:
http://faculty.washington.edu/kessler/occasionally-asked-questions.html
dscott says: “The short answer is NO. The right answer is “All things are NOT equal” therefore subtracting anything without knowing the underlying linear or non linear response of the system is invalid….”
A great discussion. Thanks.
philr1992 says:
January 17, 2013 at 8:06 am
Willis, with all due respect, your claim that ENSO SSTs modulate the trade wind/AAM phase space regime is inaccurate. You’ll find that variations in the polar annular modes, hence the associated stress fields/standing gyres, precede variations in the SOI/ONI by a few months. This circulatory behavior appears to be driven by the rocking phase of the QBO and solar wind fluxes affecting stratospheric O^3 content.
ENSO is absolutely not an internal system oscillation. It is externally forced, the SST anomaly stripe along the axial equator should be considered a result, not a causative mechanism via ludicrous positive thermodynamic feedback loops.
=================
” It is externally forced ” ? Likely, but I don’t think it’s reasonable to just assert it is so. I’ll come back to that.
To Willis’ questions, no of course it’s not “noise” neither does the fact is oscillates ( in a very vague sense of the term) mean it is a mean zero effect.
If it’s just noise a suitable low pass filter will take it out and leave any residual. Of course this is just what those who try the “noise” argument have in mind. But if it’s not mean zero then any resulting change – warming just for example – will get falsely attributed to something else such as … hmmm, Ah! AGW !!
Any attempt to model climate has to model all of it , not make arbitrary assumptions like: all change is due to human CO2 and everything else must average to zero.
A gender mix-up in that paragraph maybe?
p.s. It all has to do with the shapes and locations of the continents and the rate at which the cold waters off Antarctica spin around and around. When the spin speed increases, much cold water can’t squeeze past the narrow gap between Antarctica and South America, so it travels North along the coast of SA.
The waters of the upwelling zone off of Peru and Chile are always up to 8DegC cooler than waters to the West, causing easterly winds. When these cooler waters spread far and wide due to more upwelling, easterlies increase, signalling the start of La Nina.
If we knew what causes the rate of spin of Antarctic waters to change, (possibly extra-terrestrial) we’d know a little more about the ENSO phenomena.
Tim Ball says:
January 17, 2013 at 8:38 am
Thanks, Tim. Your comments as always are interesting.
Mmmm … that’s not the case. I’m sorry that my explanation wasn’t clearer. Let me try again.
El Nino is characterized by warm water across the tropical Pacific. Over time this increases the easterly trades, which pump the warm tropical surface water first westward. The water then splits and moves polewards. In the process most of the warm surface water is removed from the Pacific, leading to La Nina conditions.
As these masses of warm tropical Pacific surface water move poleward they move under cooler and cooler atmospheric temperatures. Since the rate of energy transfer is proportional to ∆T, the air-sea temperature difference, this changes the total heat going into the atmosphere.
The same change in reverse is going on in the tropics. After the warm surface waters have been stripped and pumped poleward by the wind, the subsurface waters are cooler than before. This alters the total heat going into/out of the atmosphere.
Your contributions are always welcome,
w.
Are you saying that a value of a subset that’s 2.4% is being subtracted from the total 100% set?
This is my latest model of Hadcrut4 monthly back to 1871 based on Nino 3.4, the AMO, Solar TSI, Volcanoes AOD, and a Ln(CO2) warming trend.
This is no fluke.
http://s2.postimage.org/xbe6i3cfd/Hadcrut4_Model_Nov12.png
The Ln(Co2) warming residual is this (including the AMO as a natural cycle).
http://s8.postimage.org/hb6q21t5x/Hadcrut4_Warming_with_AMO.png
And when you leave out the AMO, you get a 60 year up and down cycle as shown here. (Chart also notes the starting point of Tamino and Rahmstorf’s 2011 paper which left out the AMO on purpose (and used the old PMOD composite data for TSI which is known to be suffering from degradation in the instruments in recent years).
http://s13.postimage.org/u9ciffzqf/Hadcrut4_without_AMO.png
rgbatduke says:
January 17, 2013 at 9:29 am
….They, not the threat of a supposed apocalypse that might or might not happen in a century, are the moral imperative of the twenty-first century. There is no need for 1/3 of the world’s population to live in squalid misery — not any more. We have the technology, we have the wealth, to utterly eliminate global poverty within a few decades. What we lack is the will and the vision to do so.
And we will never succeed in doing so at the same time we make energy more expensive and discourage its use. The poverty in question is energy poverty. Fundamentally. With enough, cheap enough, energy, we can make the deserts bloom, create jobs in the heart of Africa or India or South America, bring medicine and electric lights and running water to the world. Cheap, clean energy solves all problems; it is the fundamental scarcity.
>>>>>>>>>>>>>>>>>>>>>>>
That we have a large number of people in the industrialized nations who WANT to return to those conditions and are being organized to push for legislation forcing their entire country in to becoming like those African countries is to me truly mind boggling.
We have had the technology to improve those conditions for decades but instead the bankers and corporations with the help of our governments do all they can to make conditions even worse. see link for a typical scenario
Great questions, Willis. Great discussion, everyone. Thanks. I heartily endorse the comment by rgbatduke, especially the following:
“In a century, we probably will be able to make quantitative climate predictions with some skill. In the current decade, we cannot. AGW is by no means disproven by the last 15 to 18 years of arguably flat temperatures, just as it was by no means proven by the temperature rise that occurred during the ENSO event or since the end of the LIA or the Dalton minimum. Temperature change cannot either prove or disprove the (C)AGW hypothesis, not without a full understanding of the climate system sufficient to predict what the temperature would be in the absence of extra CO_2, which we utterly lack.”
That is an accurate description of where climate science is today.
Bob Tisdale:
In your superb and informative post at January 17, 2013 at 10:07 am you say to Willis,
As I said in my post January 17, 2013 at 7:25 am, at I strongly agree that “Under no circumstances should they [i.e. ENSO effects] be treated as noise”. But I write to make a pedantic point which I think to be important.
Climate system oscillations such as ENSO, AMO, etc. are emergent properties of the system. They are not simulated in the climate models because emergent properties cannot be simulated without adequate understanding of the emergent behaviour. This provides a problem; viz.
When a model of a complex system is constructed, the emergent properties of the system
(a) arise naturally in a model’s output
or
(b) have to be simulated as an input simulation of the behaviour which will alter the model’s output.
There is reason to accept that the model provides a realistic emulation of a complex system if an important emergent property of the system arises in the model’s output.
Failure of the model to generate an important emergent property indicates that the model is a poor emulation of the modeled system. And if the model is forced to simulate an important emergent property of the system then it cannot be known in what other ways the model output differs from the behaviour of the modeled system.
But ENSO, AMO, etc. do not arise in the output of climate models and there is lack of knowledge to enable these behaviours to be simulated in the models. This indicates that the models are poor emulations of real climate behaviours and their causes.
Hence, there is no a priori reason to accept outputs of climate models as being indicative of the behaviour of the real climate. And, therefore, studies such as yours have extreme importance for understanding real climate behaviour.
Richard
Paul Homewood says: “If La Nina results from the trade winds, which themselves result from El Nino conditions, then what causes a double or triple La Nina?”
A clarification: Trade winds (and westerlies) exist at some degree during all phases of ENSO. During ENSO-neutral phase, the trade wind strength is “normal”. During a La Niña, trade winds strengthen across tropical Pacific. And during an El Niño, the trade winds in the east weaken, and those in the west reverse and become westerlies.
Keep in mind that ENSO is a coupled ocean-atmosphere process and that the trade winds and the temperature gradient (not anomalies) of the tropical Pacific interact. Stronger trade wind equal steeper temperature gradient—and a steeper temperature gradient also strengthens the trade winds—positive feedback.
Regarding the rest of your question, there are a number of other factors that dictate when and whether an El Niño and La Niña will form. They include alternating “pulses” of warm and cool waters that travel across the equatorial Pacific (from west to east) called Kelvin waves. If there isn’t a lot of warm water associated with a downwelling (warm) Kevin wave, (or enough warm water in the west Pacific Warm Pool to serve as fuel once an El Niño gets underway), an El Niño may not form or it will be short lived. Recently, there appears to have been more cool water than normal associated with the upwelling (cool) Kelvin waves, so we’ve had the double-dip (2010/11 La Niña and 2011/12 La Niña) and now La Niña conditions—though I don’t know that we could classify this as a triple-dip, since we did reach strong El Niño conditions for a short period of time during 2012.
La Niña events can also simply last for three years, as we saw with the 1998-2001 La Niña. ENSO involves positive feedbacks, as noted above, so an ENSO event requires something to break the positive feedback in order to come out of a La Niña (or El Niño). I suspect that 3-year La Niña lasted so long because there was so much warm water in the western tropical Pacific (that was left over from the 1997/98 El Niño) that the tropical Pacific simply got stuck in La Niña mode until the warm water was distributed and dissipated. Makes sense, but I haven’t seen any papers describing it. (The unfortunate thing: most ENSO papers deal with El Niños, not La Ninas.)
I think Bob Tisdale’s basic argument that cold la Nina surface conditions allow increased solar energy capture and El Nino dumps OHC into the atmosphere (and hence starts its way out of the global system) is fundamental. As he says, it’s asymmetric , it is not two sides of the same coin and there is absolutely no reason why is should be mean zero.
Anyone suggesting this is “noise” or internal variation has likely not thought it through or is trying to pull a fast one.
However, this just provides a mechanism. The question is what drives it.
Now one factor I have not had time to properly investigate is but has been nagging me for a while is the idea that the way the colder waters surface of Peru suggests to me an upwelling of water striking the massive underwater mountain that is South America. Diagrams like upper part of Willis’ figure 2 look like a basin wide oscillation to me , not winds pushing some surface water to one side.
What I’d like to see is how these up-wells correlate with length of day variations.
It is fairly well accepted in attempts to model tides that basin wide or regional tides have an effect on LOD. It follows by Newtons third law of motion, that if tides can affect LOD, LOD can affects tides. Now tides are generally accepted to be driven by celestial bodies though actually trying to model it gets rather …. tricky.
Now if some such celestial body or bodies exerted a pull on the highly asymmetrical solid Earth “potato” that would cause a small change in angular momentum and hence a change in LOD.
In the sense that is shortens the LOD the liquid part of the earth would invoke Newton’s first law and carry on moving. It would run up the slope of S. Am and colder (ie denser) deeper waters would rise towards the surface. If this change was repeated for months (or years) , as LOD changes do, this could well cause something like what we call La Nina conditions.
Once this change of angular momentum fades , the denser waters would fall back being replaced by warmer surface waters being draw back by gravity.
Since the mass of water involved is huge and the relative difference in density relatively small the time constant of this movement would be very long . Indeed deeper waters, larger effects would be longer again. The driving force would necessarily be a very slow one.
There has been a lot of speculation about various complex periodic changes in climate and possible linkage to planetary orbital periods. This could provide a possible mechanism.
Similar effects may also affect other major basins, where periods would be different and probably resonate with different drivers.
Autocorrelation lags plots of both N. Pacific and N. Atlantic shows strong periodic repetitions.
I may get to post more detail on that later.
This is a helpful post, the ENSO should indeed be seen as a heat pump.
The heart is also a pump. The analogy is not completely misplaced since both the metazoan heart-beat and the ENSO are nonlinear oscillators.
This debate is settling into the familiar internal versus external oscillation debate.
What Willis has described in terms of the interaction of the trades blowing equatorial Pacific water westward, cloud cover and upwelling in the east Pacific is a concise description of the Bjerknes feedback, described here.
The crucial understanding that Bjerknes brought to the ENSO is that both La Nina and el Nino phases are driven by positive feedbacks. They are time-limited positive feedbacks since their operation leads to remove the conditions driving the positive feedback.
Since the wind and current setup of the Pacific can lead periodically to either of these feedbacks, the Pacific thermodynamically can be described as an “excitable medium” or a reactive medium. This is the condition that leads to nonlinear oscillation (see Bertram). The classic Belousov-Zhabotinsky chemical oscillator is a good example of this.
The heartbeat, as mentioned initially, is also a nonlinear oscillator – it is driven by very strong positive feedbacks, with the result that the emergent oscillation is regular and monotonic, and with strong amplitude. By contrast the Bjerknes positive feedbacks which make the Pacific an excitable medium are of limited strength, thus the oscillation is intermittent since the system is subject to various other influences.
Alan Millar says:
January 17, 2013 at 7:33 am
Succinct post Willis.
However, what causes the 30 year positive and negative PDO cycles which have more El Ninos or La Ninas respectively? We don’t see 30 year cycles in the source of the energy for this heat pump, the Sun.
Alan
Following on from the ENSO being a nonlinear oscillator, such nonliear systems typically evolve in a manner dictated by attractors. One common such attractor is the Lorenz attractor, whose waveform is illustrated here. The gtract plots show alternating periods of low and high oscillation swings, analogous to alternating periods of La Nina and el Nino dominance in the East Pacific.
The 60 year oscillation could represent the two alternating “wings” of the Lorenz attractor governing the ENSO nonlinear oscillation.
“David L. Hagen says For quantitative results, I recommend using the polynomial cointegration methodology”
No. Why should you have any faith in the results yielded by such mathematical prestidigitation? Where is the empirical evidence showing the techniques work?
According to this author, cointegration techniques are confusing, unreliable, and dangerous. IIRC he explains how the techniques can be used to show anything, depending on the biases of the user. See http://www.capco.com/capco-institute/capco-journal/journal-32-applied-finance/the-failure-of-financial-econometrics-asses
Cointegration has been used primarily in econometrics. But this is damning: “Certain hypotheses about econometric methods have been accepted for years despite the lack of evidence. Ninety-five percent of the experts agreed that econometric methods are superior for short-range forecasting. An examination of the empirical literature did not support this belief: Econometric forecasts were not shown to be significantly better in any of the 14 ex post and 16 ex ante tests. Furthermore, there was no tendency toward greater accuracy over these 30 tests. Similarly, 72% of the experts felt that complexity contributed to accuracy, but the examination of the literature did not support such a belief: Complex models were not significantly better in any of the five indirect and 11 direct tests.” – from http://works.bepress.com/j_scott_armstrong/46/ and http://repository.upenn.edu/cgi/viewcontent.cgi?article=1008&context=marketing_papers
Bill Illis,
Are you saying, that you have isolated the CO2 warming trend?
Bill Illis,
Nevermind, I got it…
There are a lot of good mathematical/statistical observations in the post and comments. But I feel that the primary failure in trying to define these large effects as “noise” is a simple misuse of language, in the Orwellian sense. If the data is inconvenient, slander it as :”noise”.
A proper definition of noise would not include the data which is coupled to the signal of interest in any way by feedback or control as noise. For example the cosmic microwave background can be safely removed from the microwave observations of a single star of interest, since they are not coupled or correlated. The AGW crowd’s attempt to turn these oscillations into “noise” is logically as ridiculous as trying to understand a pulsar by first filtering out the pulses.
On our trpospheric scatter radio system we had four receivers with phase correctors which when combined would pull the signal up out of the noise. The theory was that the noise being random would remain at the same level whilst the in phase signals would add together giving a 6db gain.
Perhaps you could adapt the theory Willis.
Number of contributors have mentioned the equatorial heat transport pole-wards.
In the North Atlantic and the North Pacific heat transport is regulated by conflict of warm and cold currents: North Atlantic Drift and East Greenland Currents (NA) as drivers of the AMO, Kuroshio and Oyashio Currents (NP) driving the PDO, while in Central Pacific the South Equatorial Current is the key oscillator, the source of the ENSO.
http://www.vukcevic.talktalk.net/A&P.htm
In the far South Pacific the Antarctic Circumpolar Current (ACC) is the main oscillator driving the Antarctic Circumpolar Temperature Wave (ACTW).
The AMO, PDO and ENSO can be directly linked to the Earth’s tectonics by examining geological records
while the ACTW appears to be related to an oscillation in the differential rotation of the Earth’s core.
To understand the Earth’s climate change through changes of the oceans behaviour, some appreciation of the changes that the Earth exerts on the above mention currents appears to be an essential prerequisite, sadly ignored by many.
rgbatduke well said,I have not read a better synopsis.
gail combs
That we have a large number of people in the industrialized nations who WANT to return to those conditions and are being organized to push for legislation forcing their entire country in to becoming like those African countries is to me truly mind boggling.
This is a great point and highlights a consequence of the Progressive agenda playing out before our eyes. If Progressives have their way, tax rates will increase on everyone in the U.S., not just the “rich”. The payroll tax holiday that ended January 1, 2013 is a small example. It was a mere 2% of wages, but hit rich and poor alike, with the poorest workers paying the highest effective rate in terms of income since nearly all their income is wage income and subject to the tax.
The Progressive push for a reduction in take-home pay and increase in the global price of energy will, as you implied, force rich and poor alike to accept a lower standard of living.
To return to the original question, why treat this effect as noise?
In a very simple model, the output is presumed to be some linear multiplier times each factor, plus a constant. O = M1 * F1 + M2 * F2 + C
There is one multiplier, M1 and M2 for each factor F1 and F2, and so on.
Your goal is find M1, M2, and C. The way you do that is cancel out factor F1, so whatever is left is driven solely by F2, then vice versa. The proper way to do that operation is to find data where F1 is a high value, then a low value, while F2 is absolutely unchanging, then vice versa.
A more sophisticated approach might look for more than 2 values of F1, all while F2 is held rock steady. That would see whether the response to F1 is something besides a simple multiplier.
As always, this operation is only as good as its assumptions and its execution. If there is some other big factor F3 which you are not accounting for, the whole approach is going to drive into a concrete post and crash. Let alone F10 and F25. And if history and the order of events is important, you drive into that post and crash. And if F1 and F2 react with each other, so the effect of F1 depends on whether F2 is high or low, you have another big problem. If there are more than about 2 driving factors, such as N=8, the work to cancel out each set of N-1 factors (here 7 factors at the same time) while wiggling the remaining factor becomes prohibitive, unless you have a nice laboratory and can apply the very orderly techniques of Design of Experiments (DOE).
If you don’t have clean experiments like that (and weather experiments won’t), you can try to analyze naturally occuring data (NOD). This often involves introducing the concept of noise, which means you are trying to find the effects of factor F1 by subtracting out the effects of factor F2, rather than holding it steady (presuming there are no other important factors out there wiggling away by themselves at the same time, and so on.). Crucial assumptions include independence, and that you have successfully kept an eye on every single one of the actual drivers. Otherwise, you have a lovely history, but it is totally useless as far as its predictive value. Good try, but no kewpie doll.
And subtracting out just one of the driving factors is useless, too. You have to account for all of them, or you have no clue what remains. The trifecta is the only game in town, and you missed it.