The 2007-2008 Global Cooling Event: Evidence for Clouds as the Cause
September 26th, 2009 by Roy W. Spencer, Ph. D.
As I work on finishing our forcing/feedback paper for re-submission to Journal of Geophysical Research – a process that has been going on for months now – I keep finding new pieces of evidence in the data that keep changing the paper’s focus in small ways.
For instance, yesterday I realized that NASA Langley has recently updated their CERES global radiative budget measurement dataset through 2008 (it had previously ran from March 2000 through August 2007).
I’ve been anxiously awaiting this update because of the major global cooling event we saw during late 2007 and early 2008. A plot of daily running 91-day global averages in UAH lower tropospheric (LT) temperature anomalies is shown below, which reveals the dramatic 2007-08 cool event.
I was especially interested to see if this was caused by a natural increase in low clouds reducing the amount of sunlight absorbed by the climate system. As readers of my blog know, I believe that most climate change – including “global warming” – in the last 100 years or more has been caused by natural changes in low cloud cover, which in turn have been caused by natural, chaotic fluctuations in global circulation patterns in the atmosphere-ocean system. The leading candidate for this, in my opinion, is the Pacific Decadal Oscillation…possibly augmented by more frequent El Nino activity in the last 30 years.
Now that we have 9 years of CERES data from the Terra satellite, we can more closely examine a possible low cloud connection to climate change. The next figure shows the changes in the Earth’s net radiative balance as measured by the Terra CERES system. By “net” I mean the sum of reflected shortwave energy (sunlight), or “SW”, and emitted longwave energy (infrared) or “LW”.
The changes in the radiative balance of the Earth seen above can be thought of conceptually in terms of forcing and feedback, which are combined together in some unknown proportion that varies over time. Making the interpretation even more uncertain is that some proportion of the feedback is due not only to radiative forcing, but also to non-radiative forcing of temperature change.
So the variations we see in the above chart is the combined result of three processes: (1) radiative forcing (both internal and external), which can be expected to cause a temperature change; (2) radiative feedback upon any radiatively forced temperature changes; and (3) radiative feedback upon any NON-radiatively forced temperature changes (e.g., from tropical intraseasonal oscillations in rainfall). It turns out that feedback can only be uniquely measured in response to NON-radiatively forced temperature changes, but that’s a different discussion.
The SW component of the total flux measured by CERES looks like this…note the large spike upward in reflected sunlight coinciding with the late 2007 cooling:
And here’s the LW (infrared) component…note the very low emission late in 2007, a portion of which must be from the colder atmosphere emitting less infrared radiation.
As I discuss at length in the paper I am preparing, the physical interpretation of which of these 3 processes is dominant is helped by drawing a phase space diagram of the Net (LW+SW) radiative flux anomalies versus temperature anomalies (now shown as monthly running 3-month averages), which shows that the 2007-08 cooling event has a classic radiative forcing signature:
The spiral (or loop) pattern is the result of the fact that the temperature response of the ocean lags the forcing. This is in contrast to feedback, a process for which there is no time lag. The dashed line represents the feedback I believe to be operating in the climate system on these interannual (year-to-year) time scales, around 6 W m-2 K-1 as we published in 2007…and as Lindzen and Choi (2009) recently published from the older Earth Radiation Budget Satellite data.
The ability to separate forcing from feedback is crucial in the global warming debate. While this signature of internal radiative forcing of the 2007-08 event is clear, it is not possible to determine the feedback in response to that temperature change – it’s signature is overwhelmed by the radiative forcing.
Since the fluctuations in Net (LW+SW) radiative flux are a combination of forcing and feedback, we can use the tropospheric temperature variations to remove an estimate of the feedback component in order to isolate the forcing. [While experts will questions this step, it is entirely consistent with the procedures of Forster and Gregory (2006 J. Climate) and Forster and Taylor (2006 J. of Climate), who subtracted known radiative forcings from the total flux to isolate the feedback].
The method is simple: The forcing equals the Net flux minus the feedback parameter (6 W m-2 K-1) times the LT temperature variations shown in the first figure above. The result looks like this:
What we see are 3 major peaks in radiant energy loss forcing the system: in 2000, 2004, and late 2007. If you look at the features in the separate SW and LW plots above, it is obvious the main signature is in the SW…probably due to natural increases in cloud cover, mostly low clouds, causing internal radiative forcing of the system
If we instead assume a much smaller feedback parameter, say in the mid-range of what the IPCC models exhibit, 1.5 W m-2 K-1, then the estimate of the radiative forcing looks like this:
Note the trend lines in either case show a net increase of at least 1 W m-2 in the radiant energy entering the climate system. The anthropogenic greenhouse gas component of this would be (I believe) about 0.4 W m-2, or a little less that half. I’ll update this if someone gives me a better estimate.
So, what might all of this mean in the climate debate? First, nature can cause some pretty substantial forcings…what if these occur on the time scales associated with global warming (decades to centuries)?
But what is really curious is that the 9-year change in radiative forcing (warming influence) of the system seen in the last two figures is at least TWICE that expected from the carbon dioxide component alone, and yet essentially no warming has occurred over that period (see first illustration above). How could this be, if the climate system is as sensitive as the IPCC claims it to be?
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Robert Mackey,
What is the period of the interaction between this 18.6 year LNC and the 22 year solar magnetic cycle? Might we find another climactic cyle there? Perhaps also a minor one in the interaction of the 18.6 and the (roughly!) 11 year activity cycle? The variation in pitch between the Saros cycle and the LNC suggest the possibility of another long-scale cycle. I suspect that there are even more cycles invovled. If we overlay them and add and subtract the vectors correctly I wonder how good a fit we will find?
Now, due to lack of sufficient 1, 3,7 trimethylxanthine, my head is going to explode.
“”” Joel Shore (17:36:42) :
George,
What you describe is essentially what happens in any field of science. If you start to dig into it, then there will be a lot of things that are just sort of taken for granted by the scientists in the field because they were settled decades ago. (And, indeed, most of these issues that you seem stuck on involving radiative physics and such were serious objections 40 or 50 years ago, but have since been settled. The very end result of the climate sensitivity is not settled, but that is because getting from the radiative forcing to the temperature response involves all the possible feedback effects in the atmosphere.)
And, so you have two choices: You can either accept that the scientists figured them out correctly. Or, you can dig up all the original work again and go through it and either decide that it is correct or come up with a good argument as to why it is not. However, I think just saying that it doesn’t seem right to you without investing the time to understand how the conclusion was reached is, in my opinion, not a very good option. It is extremely immodest to basically say that you know better than these scientists even though they have invested many years of study in the problem and you are just talking off the top of your head or on the basis of what you know by analogy from other fields.
As for the part about the developed world being led back to the dark ages: I think, in fact, this is the crux of the matter. — You don’t like the policies that are being proposed to deal with this problem and that pre-disposes you to believe that the science is wrong because that way you can argue that the policies are unnecessary.
And, just as a thought experiment, if I told you that we were running out of fossil fuels and would have to wean ourselves off of them over the next half century or so, would you still say that we were going to end up having to go back to the Dark Ages? And, if not, what exactly is the difference…except that, in the current situation, we have the additional flexibility of continuing to burn fossil fuels if we find an economical way to sequester the CO2? “””
Well Joel I agree with your comment that scientists accept things that were settled decades ago.
For example in a climate related instance; for over 60 years; six decades, and double the typical climatology base line periods that people select; and a very long time in the history of any modern science; it was beleived as gospel that when liquid water droplets freeze (presumably in clouds) that they freeze from the INSIDE OUT. No; we are not talking about the multilayer deposition process which typically forms hailstones; simply the freezing of a pre-existing water drop.
But it was proven by Azadeh Tabazadeh (NASA Ames) that that is completely eroneous, and they in fact freeze from the outside in. So in rapidly developng sciences, it is not unusual for long held dogma to get overturned.
And the trouble with climate research before the space age, is that the data to feed some of these computer simulations simply was not available; not that the computers were either.
Christy et al in 2001 presented a paper on oceanic buoy data of about 20 years duration whose underlying message, was that temperature sampling data over 73% of the earth’s surface (the oceans) prior to about 1980 when those buoys were first deployed was essentially unusable and uncorrectable because it was found that oceanic water and air temperatures aren’t correlated; whereas it was previously assumed that they were in fact the same. since they are not correlated, then air temperature data cannot be reconstructed for the useless water temperature data that was gathered over 150 years or so. Well it might be of use in tracking water surface temperatures; but can’t be melded into lower troposphere data obtained from land based sensors; Anthony’s infamous Owl box collection.
I’m not the one who is saying that the computer GCMs don’t model clouds correctly; the modellers themselves say that. I’m not surprised, since we have no way to monitor cloud cover the way Mother Nature monitors it; even with satellites there is no continuous total global cloud cover measurement; and clouds come and go in minutes, so orbiting satellites can only sample at quite inadequate intervals. Gaia monitors the cloud cover down to picosecond time intervals, and at spatial scales of nanometres; continuously; so she gets the right answer. We can’t do that, so we get only wrong answers.
and the whole point about the climate sensitivity issue, is that it is not a fixed property of CO2. The climate sensitivity at Vostok Station is not even vaguely close to the climate sensitivity in the middle of death valley or in the Hawaiian islands. So it is not a useful quantity at all, so they try to come up with some average value. There’s no computational way to do that, since there is no adequate sampling network to sample climate sensitivity globally to properly compute an average for the whole earth.
And the whole concept only yields some sort of radiation imbalance that cannot be simply converted into a temperature change; because there are other much more powerful effects going on that swamp whatever the CO2 might be doing.
And nowhere have I ever said that I know better than “these scientists”, whoever they may be. My comments are nearly always restricted to subject matters that I have only been working with for about 50 years. I agree that is not long compared to the billions of years of climate proxy data that the experts have been working with.
I’ve already told you that I’m not really interested in studying climate. The ins and outs of ENSO and other apparent climate patterns, I am sure are of great interest to all those statisticians who love to fit straight line trend graphs to, and filter the available data to throw most of it away, in the search for information that really isn’t there to begin with. I don’t have time to study all of that; I actually have a full time job to do; and lucklily my computer is busy doing a lot of it for me, so I can catch a few moments to comment here; while it thinks for me.
But when I do spend some time listening to the climate experts and what they have to say; I immediately run into some problems. There’s an awful lot of brilliantly eminent climate scientisst; who HAVE worked in the field for decades; who simply disagree with what you are suggesting is an overwhelming settled conclusion as to man’s influence on the climate.
The rebellion against the party line is impossible to ignore Joel; and I do listen to both sides.
And yes I do get riled up when I see politicians proposing Draconian measures that are borderlng on criminal insanity to supposedly fix so-called problems whose very existence has not been proven.
As to the running out of fossil fuels; as far as the USA is concerned; the limits on our fossil fuel future useage are those that are self imposed by edict that removes known US supplies from availability. Government dictators are locking up US sources of fossil fuels as fast as they can be discovered, and simply decreeing that they can’t be used, and that decision is based on the belief that CO2 is bad for the environment.
One thing that will be bad for the environment is the permanent sequestration of atmospheric oxygen in man made deposits of the ultimate “pollutant”.
Well the problem is Joel, that there are simply too many people who realize that this whole donnybrook was deliberately created as a mechanism for an elite cliche to control the behavior of the rest of us. It has nothing to do with the environment or energy or anything else; it is all about political power and control.
I object to that; but mostly I object to the misuse of “science” to delude those who for their own reasons, are not able to follow these issues themselves; that to me is the ultimate crime.
George
Re: Richard Mackey (01:08:47)
Hi Richard,
The LNC alone only ‘explains’ (in the statistical sense) a small fraction of the variance, but consider the following, which takes into consideration both high-frequency solar system dynamics and terrestrial polar motion (in addition to the LNC):
http://www.sfu.ca/~plv/CumuSumAMO.png
http://www.sfu.ca/~plv/TPM_SSD_LNC_3_1850.png
http://www.sfu.ca/~plv/CumuSumPDO.png
http://www.sfu.ca/~plv/CumuSumPDO_AltDataSource.png
Regards,
Paul.
George E. Smith says:
Well, it may not be that unusual, but I don’t think it is common enough that the going assumption should be that it is wrong. And, the way to overturn it is to carefully study the past work in the field and come up with a good demonstration showing how or why this work is wrong. It is not just to make vague arguments of disbelief.
Yes, clouds are a legitimate source of uncertainty. But, that doesn’t mean that nothing is known or can be modeled about them. It just means that there remain significant areas of difficulty. I don’t think whether thin high clouds cause net warming or cooling is one of them.
I don’t even think the “skeptics” do themselves any service by contesting everything and anything…at least for really advancing their cause in the scientific community. (This may be a good strategy for convincing the public, but that is a different story.) It would be better if you guys conceded the stuff where the evidence is really overwhelming and stuck to arguing about the value of the climate sensitivity due to cloud feedbacks. Instead, there are people arguing about the most basic issues of the effect of clouds on climate, people claiming that the greenhouse effect violates the 2nd Law of Thermodynamics, people claiming that humans are not responsible for the rise in CO2 levels above the pre-industrial baseline, people claiming that CO2 levels were really much higher than ice core data show over the recent past, and all sorts of truly nutty things.
This paragraph is one example of where you can really benefit from reading a basic textbook on atmospheric or climate science. As it turns out, I have just been doing this myself (because I also can really benefit from this and only regret that I didn’t start doing so sooner). One book I have been reading is “Global Warming: The Hard Science” by L.D. Danny Harvey. And, Chapter 3 discusses the concepts of radiative forcing and climate sensitivity. And, what you are saying doesn’t really make sense for a few reasons. First of all, climate sensitivity is DEFINED as the change in average global temperature per given change in global radiative forcing, so to say it can be different in different places doesn’t really make sense. Now, there are questions you could ask and which in fact the author addresses. For example, one question is whether the distribution of radiative forcing (either latitudinally or in altitude) results in very different climate sensitivity. And, the answer seems to be that it doesn’t significantly in most cases (partial exceptions include ozone and absorbing tropospheric aerosols). Another question is whether the regional response depends on the distribution of the forcing…and again the answer seems to be for the most part NO…and this is simply because the troposphere has lots of flows both vertically and horizontally that mean that the distribution of warming that occurs is more a function of these flows than it is of the distribution of any change in radiative forcing. (Another interesting fact I learned is that the main surface warming effect of greenhouse gases is not actually the increase in infrared radiation from the atmosphere that makes it back to the surface but is rather the decrease in the emission of radiation back out into space because the effective emission layer moves higher in the atmosphere and hence the emission decreases via the Stefan-Boltzmann Law.)
Well, I don’t think you have been working on the radiative properties of clouds in the atmosphere for 50 years. You may have done some work on radiative issues but that doesn’t necessarily make you an expert on the radiative properties of clouds.
Well, “an awful lot” seems like an exaggeration to me. The few in the U.S. off the top of my head who I think would qualify if you relax “brilliantly eminent” to be “reasonably well-published and regarded” would be Richard Lindzen, Roy Spencer, John Christy, and Roger Pielke Sr. And, while these scientists may argue the extent of man’s influence on the climate through greenhouse gas emissions, I don’t think any of them would agree with you on the points that you have argued (regarding the effect of high clouds or what the radiative forcing due to increased greenhouse gases is). They mostly seem to argue about feedback effects.
Do you expect complete unanimity, especially given the complex policy implications of the science? What is impossible to ignore, I think, is the broad consensus of scientific organizations…and the increasing acceptance of the science by those (such as fossil fuel companies) who have considerable financial interest in questioning it (and, who indeed were part of the Global Climate Coalition back in the 90s that was doing just that until it became increasingly scientifically untenable).
You are dodging my question which was a hypothetical one. I.e., are you saying that the only thing preventing us from going back to the Dark Ages is that we have the good fortune of having a large store of fossil fuels and if this store was any significant amount less than it is, we would be doomed?
It is my experience that people who are great believers in markets and think that they can deal with problems such as resource depletion suddenly start alarmist talk about economic disaster and going back to the Dark Ages if, heaven forbid, we impose what is essentially the equivalent of resource depletion artificially in order to preserve our environment. It doesn’t seem like a consistent point-of-view to me.
This seems like a bizarre statement to me. Why do you expect that doubling or quadrupling the level of CO2 in the atmosphere would have no significant effect and yet you are worried about a fractional change in oxygen levels of less than 1 part in 100? And, why are you not concerned about this change in O2 itself…as long as the CO2 is left in the atmosphere but it becomes a big concern to you if we sequester it away. Can you explain the logical consistency of such a position?
Sounds like a grand conspiracy theory to me.
I guess we inhabit different worlds. In the world which I inhabit, it seems much more reasonable to believe that it is the Heartland Institute that is misuing science and it is the NAS, the AAAS, the APS, AMS, and AGU who are fighting this misuse than the other way around. And, of course, as I look at the science itself I become more and more convinced that this is indeed the case.
Several correspondents have asked about relationships between the 18.6 yr Lunar Nodal Cycle (LNC) and the 18.03 yr Saros cycle. Others have asked about interaction effects between solar periodicities of whatever type and the LNC. This note is a response to these queries.
It is essential to understand that the LNC and Saros cycles are fundamentally different categories.
The LNC is the period of a full rotation of the Moon’s orbital plane around the geometric plane of the Earth’s orbit around the Sun (the ecliptic). The Sun’s gravitational field makes the Moon’s Earthly orbit swivel around in a clockwise manner, over a cycle of 18.6 years, with respect the ecliptic, which is the plane of the Earth’s orbit. The Moon moves with respect to the ecliptic up and down a northerly latitude throughout the LNC. This arises because the Earth is titled on it axis and inclined away from the Sun and because the Moon’s orbit is tilted a little relative to the ecliptic. It is as if the Sun strives to pull the plane of the Moon’s orbit into its own plane, the ecliptic. But there is an alternate motion at right angles to the applied force, resulting in a revolution of the pole of the Moon’s orbit around the pole of the ecliptic.
The LNC defines how the angle of the Moon’s orbit to the Earth’s equatorial plane combines with, or partially cancels out, the tilt in the Earth’s axis. From the perspective of an observer on the Earth, during the LNC the Moon moves along a northern latitude about ten degrees from a position about 18.5 degrees north of the equator to one that is 28.5 degrees, which it reaches after 18.6 years.
The Saros cycle is a means for predicting lunar and solar eclipses. The word “Saros” means “repetition” was given to the cycle by Edmund Halley in 1691.
There is a very good entry about the Saros cycle in Wikipedia here, http://en.wikipedia.org/wiki/Saros_cycle
The Saros cycle is 6,585.277 days long, but depends on the number of leap years in the cycle. After one Saros cycle, the Earth-Sun-Moon geometry will be nearly identical: the Moon will have the same phase, be at the same node, and have the same distance from the Earth. If one knew the date of an eclipse, then one Saros Cycle later, a nearly identical eclipse should occur.
The Saros Cycle is connected to the LNC in that Saros is a simple arithmetic function of three lunar months one of which is an element of the LNC: (i) the time between lunar phases e.g. two full moons; this month is known as the synodic month. (ii) The time between two passages of the Moon at the point at which it is closest to the earth (perigee): this month is known as the anomalistic month. (iii) The time required for the Moon to return to the ascending node (i.e. crossing the ecliptic from south to north): this month is known as the nodal month (and also known as the draconic month). It is this month that links the Saros Cycle to the LNC.
The Saros Cycle was devised around the fifth or sixth century BC by Chaldean astronomers (who in those days were called astrologers) because of the absolute importance of being able to predict eclipses. They had thousands of cuniform clay tablets made by the ancient Babylonians as their data base. The Chaldean equivalent of Rajendra Pachauri knew that fame, fortune and great power would be his if he could persuade the powers-that-be that he could predict things and make the powers-that-be seem godlike to the masses. The way to do that in those days was to be able to predict eclipses more accurately than anyone else. The Saros Cycle gave the top astrologers of the day that power.
The Saros Cycle is now no more than a curiosity, an indicator of the observational skill, record keeping skills and (arithmetic) calculating skills of the ancients. We have far more sophisticated lunar ephemerides on the www than the Saros Cycle.
Nevertheless, there are two important lessons for us moderns from Saros. One is that the existence of Saros means that there must be a periodic repetition of some special geometries and that this would mean there is resonance acting within the Moon-Earth-Sun system. Resonance is ubiquitous in the solar system. Resonance is the subtle gravitational effect of Newton’s laws at work that determines the dynamical structure of the solar system; and so with the solar system’s Moon-Earth-Sun sub-system. The second lesson, taking the resonance into account, is that if there can be demonstrated relationships between lunar periodicities and our planet’s climate dynamics, we can use the mathematics of the lunar periodicities to predict climate dynamics, just as the ancient astrologers used them to predict eclipses with such great success.
Mazzarella and Palumba (1994) point out that bistable modes of oscillation with respect to time are well known in physical and engineering systems and have been extensively studied. This research from Physics and Engineering demonstrates that a sinusoidal force applied to any dynamic system induces sinusoidal periodicities in the system.
Accordingly, the LNC induces bistable sinusoidal periodicities in the atmosphere (pressure, temperature and rainfall) and the ocean (temperature and sea level). The sinusoidal, highly stable 18.6 year LNC has a distinctive and significant effect on the Earth’s climate dynamics.
There is a substantial published literature that shows the significant role of the LNC in regulating our planet’s climate dynamics. Amongst other things, it is largely responsible for the Pacific Decadal Oscillation.
The Arctic Oscillation (AO) is regulated by the solar cycle in a non-linear manner. Heightened and weakened solar activity activates the large Rossby and Kelvin waves.11 The effects of these waves on atmospheric circulation are intensified by the creation of Ozone during times of increased solar activity. The AO is stronger with more zonal circulation over mid-latitudes, especially in the European-North Atlantic sector, and more variable during the peak of the solar cycle.
The AO is also regulated by the peak 9.3 year and 18.6 year LNC tidal oscillations. The processes by which the effect occurs are different from those of variable solar activity. The tidal oscillation impacts on atmospheric circulation and on the large Rossby and Kelvin waves. It also impacts on the churning of the oceans.
Nevertheless, the two solar processes interact amplifying each other’s contribution.
The AO has a key role in Northern Hemisphere climate variability and its behaviour is largely the result of the interaction of the solar cycle and the 9.3 and 18.6 year LNC tidal oscillations.
Berger (2007) found that solar modulation of the NAO is amplified by tidal cycles. He found that there is non-linear resonance between solar cycles and tidal cycles, especially the LNC and the perigean tidal cycle the effect of which is to amplify solar modulation of the NAO.
Treloar (2002), of the Queensland Centre for Climate Applications, Queensland Department of Primary Industries, reported that the variability in ENSO and seasurface temperature anomalies is partly a result of lunisolar tidal factors.
The Moon and the Sun periodically amplify each other’s gravitational effect on the Earth in a non-linear manner that closely correlates with major earthquakes. These periodic non-linear amplifications produce elastic energy that resides in the Earth’s core and crust. Barkin and Ferrandiz (2004), Barkin et al (2005) and Barkin et al (2007) demonstrated that the variable gravitational field of the Sun, interacting with the Moon’s, generates a range of significant periodic changes amongst the Earth’s shell-like structures: atmosphere, oceans, liquid core, mantle, another layers and plates.
Barkin and Ferrandiz (2004) derived an analytic expression for the elastic energy of planet tidal deformations induced by other bodies, including the central star, in a planetary system.
The elastic energy is not simply a sum of the elastic energies of the separate pairs of bodies but contains additional terms which are non-linear functions of the superposition of the variable gravitational fields of the Sun, Moon and other planets. As a result, there are large and significant variations in conditionally periodic variations in the elastic energy of the gravitational fields of the Sun and the Moon, especially, but with additional coefficients for the planets.
Some of the elastic energy is dissipated as heat and contributes, as the periodicities of the tides determine, to the warming of the Earth and the oceans. Most of the remainder is retained in the solid material of the Earth, resulting in deformations, ultimately in the form of earthquakes and volcanoes. Some of the elastic energy is retained by the Moon, resulting in moonquakes which correlate closely with earthquakes.
The Moon and the Sun periodically amplify each other’s gravitational effect on the Earth in a non-linear manner that closely correlates with major earthquakes. Major earthquakes and moonquakes coincide with extreme variations in tidal elastic energy. The large additional mechanical forces and moments of interaction of the neighbouring shell-like structures of the Earth have significant impacts on climate dynamics, including the sea level. They produce cyclic perturbations of the tensional state of the shell-like structures, including deformations, small relative translational displacements and rotational oscillations, and the redistribution of the plastic and fluid masses of which the planet is composed. These additional forces and moments of a cyclic solar system nature produce deformations throughout the all layers of the Earth, regulating variations of almost all natural processes.
Apart from the immediate catastrophes that earthquakes and volcanoes induce, there are also longer term climate change consequences. These non-linear gravitational effects of the Sun and the Moon on climate change can be calculated with reasonable precision.
Here are some other well-established relationships:
• LNC maximum jointly with a Hale cycle minimum results in severe drought in the western US.
• LNC, in conjunction with resonance from the Rossby wave locked topographically into position by the Tibetan Plateau and the Rocky Mountains, most likely induced Northern Hemisphere droughts.
• LNC, in the Arctic, accelerates the warming effect of other solar processes, contributing to the melting of the Arctic ice and higher sea surface temperatures at northern latitudes. As a result, there is a larger volume of liquid water to respond to the tidal forces. In addition, the changes in ocean stratification that follow improve the mixing efficiency.
• LNC effects interact with the seasons because of the relationship between the tilt of the plane of the Earth’s equator in relation to the ecliptic (which causes the seasonal changes and the regular seasonal movements of the Sun north and south of the equator) and the rotation of the Moon’s orbital plane. Once every 18.6 years the plane of the Earth’s equator will tilt above the ecliptic in the same direction as the plane of the Moon’s orbit will tilt below it.
References
Barkin, Yu, Ferrandiz, J., Ferrandez, M. G., Navarro, J., 2007. Prediction of catastrophic earthquakes in 21 century. Geophysical Research Abstracts, Vol. 9, 08643, 2007, SRef-ID: 1607-7962/gra/EGU2007-A-08643.
Barkin, Yu. V. and Ferrandiz, J. M., 2004. Tidal Elastic Energy in Planetary Systems and its Dynamic Role. Astronomical and Astrophysical Transactions, 23, (4), 369 – 384.
Barkin, Yu. V. and Ferrandiz, J. M., and Ferrandez, M. G., 2005. Earth, Moon, Mercury and Titan, seismicity: Observed and expected phenomena. 36th Lunar and Planetary Science Conference (2005), Abstract #1076. The paper is available here:
http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1076.pdf
Berger, W. H., 2007. Solar modulation of the North Atlantic Oscillation: Assisted by the tides?
Quaternary International, 188, 24-30; doi:10.1016/j.quaint.2007.06.028.
Mazzarela, A. and Palumbo, A., 1994. The Lunar Nodal Induced-Signal in Climatic and Ocean Data over the Western Mediterranean Area and on its Bistable Phasing, Theoretical and Applied Climatology 50, 93-102.
Treloar, N. C., 2002 Luni-solar tidal influences on climate variability. International Journal of Climatology 22 No: 12 pps: 1527-154 2002 DOI: 10.1002/joc.783.
Here are some others:
Camuffo, D., 2001. “Lunar influences on climate”Earth, Moon and PlanetsVols. 85-86: pps 99-113.
Cerveny, R. S. and Shaffer, J. A., 2001. “The Moon and El Nino”Geophysical Research Lettersvol 28, No. 1. pps 25-28. Chain, A. C-L., Kamide, Y., Rempel, E.L., and Santana, W. M., 2006. “On the chaotic nature of solar-terrestrial environment: Interplanetary Alfven intermittency”. Journal of Geophysical Researchvol111, A07S03, doi:10.1029/2005JA011396.
Cook, E. R., Meko, D. M. and Stockton, C. W. 1997. “A new assessment of possible solar and lunar forcing of the bidecadal drought rhythm in the western United States”. Journal of Climate vol 10 pps 1343 -1356.
Currie, R. G., 1987. “Climatically induced cyclic variations in United States crop production: Implications in economic and social science”, in Erickson, G. and Smith, C. R. (eds) Maximum Entropy and Bayesian Methods in Science and Engineering Cambridge: Cambridge University Press 1987.
Currie, R. G. 1987. “Examples and Implications of 18.6 and 11 year Terms in World Weather records” Chapter 22 in Rampino, Michael R., Sanders, John E., Newman, Walter S., and Konigsson, L. K., Climate: History, Periodicity, and Predictability. Essays in honour of the 70th Birthday of Rhodes W Fairbridge. Van Nostrand Reinhold USA. Currie, R. G. 1995. “Variance contribution of Mn and Sc signals to Nile River Data over a 30-8 Year bandwidth” Chapter 3 in Finkl, Charles W., (Editor) Journal of Coastal Research, Special Issue No. 17, Holocene Cycles: Climate, Sea Levels, and Sedimentation. A Jubilee Volume in Celebration of the 80thBirthday of Rhodes W. Fairbridge. Coastal Education and Research Foundation.
DaSilva, R. R., and Avissar, R., 2006. “The impacts of the Luni-Solar Oscillation on the Arctic Oscillation”. Geophysical Research Letters 32, L22703, doi:10.1029/2005GL023418,2005.
McKinnel, S. M. and Crawford, W. R., 2007. “The 18.6-year lunar nodal cycle and surface temperature variability in the north-east Pacific”. Journal of Geophysical Research vol 112, C02002,doi:10.1029/2006JC003671; 15 pps.
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