This essay by Paul Vaughn is very interesting because it shows correlation between cosmic rays (via neutron count), terrestrial angular momentum, and length of day. – Anthony
Semi-Annual Solar-Terrestrial Power
Guest Post by Paul L. Vaughan, M.Sc.
Using different methods, I have confirmed the findings of the following paper:
Le Mouël, J.-L.; Blanter, E.; Shnirman, M.; & Courtillot, V. (2010). Solar forcing of the semi-annual variation of length-of-day. Geophysical Research Letters 37, L15307. doi:10.1029/2010GL043185.
I have also verified that the results extend directly to global atmospheric angular momentum (AAM):
CR = cosmic rays (neutron count rate)
LOD = length of day (inversely relates to earth rotation rate)
AAM = global atmospheric angular momentum (in layman’s terms, “global wind”)
‘ indicates rate of change
Le Mouël, Blanter, Shnirman, & Courtillot (2010) did not use complex wavelet methods, nor did they directly extend their analysis to AAM’, so the preceding results establish:
A) the robustness of the original result for LOD’ across differing methodology.
B) direct extensibility of inferred results to AAM’, even though AAM is known to have less power than LOD at the semi-annual timescale [for example, see Schmitz-Hubsch & Schuh (1999), listed below].
Cautionary Notes:
1) Sensible interpretation of the preceding data exploration requires awareness of the confounding of numerous solar variables.
2) Extrapolation of the pattern to other eras might require assumptions that cannot be physically substantiated using current mainstream knowledge.
Supplementary
1. The (max-min normalized) time series:
2. WUWT articles citing Le Mouël, Blanter, Shnirman, & Courtillot (2010):
a) Full article by Anthony Watts:
“Length of day correlated to cosmic rays and sunspots” (Oct. 3, 2010)
http://wattsupwiththat.com/2010/10/03/length-of-day-correlated-to-cosmic-rays-and-sunspots/
b) First mention (Aug. 28, 2010):
http://wattsupwiththat.com/2010/08/28/weekly-climate-news-roundup/
3. Concise primers for those lacking familiarity with AAM/LOD relations:
a) Schmitz-Hubsch, H.; & Schuh, H. (1999). Seasonal and short-period fluctuations of Earth rotation investigated by wavelet analysis. Technical Report 1999.6-2 Department of Geodesy & Geoinformatics, Stuttgart University, p.421-432.
http://www.uni-stuttgart.de/gi/research/schriftenreihe/quo_vadis/pdf/schmitzhuebsch.pdf
b) Zhou, Y.H.; Zheng, D.W.; & Liao, X.H. (2001). Wavelet analysis of interannual LOD, AAM, and ENSO: 1997-98 El Nino and 1998-99 La Nina signals. Journal of Geodesy 75, 164-168.
http://202.127.29.4/yhzhou/ZhouYH_2001JG_LOD_ENSO_wavelet.pdf
Such results have been addressed by many authors. Nonrandomness is evident using even the crudest high-frequency interannual filter [f(x) = 1 year moving average minus 3 year moving average]:
SOI = southern oscillation index (the “SO” part of ENSO)
QBO = quasi-biennial oscillation (of stratospheric winds)
4. Select passages from Le Mouël, Blanter, Shnirman, & Courtillot (2010):
a) “The zonal winds contributing to lod seasonal variations are dominantly low altitude winds.”
b) “[…] solar activity can affect the radiative equilibrium of the troposphere in an indirect way, which cannot be simply deduced from the magnitude of TSI variations.”
c) “The semi-annual oscillation extends to all latitudes and down to low altitudes, as does the annual term. But, unlike the annual term, the main part of the oscillation is symmetrical about the equator; the partial cancellation of the angular momentum of the two hemispheres, which occurs for the annual oscillation, does not happen there [Lambeck, 1980]. Thus, we have here a measure of the seasonal variation of the total angular momentum of the atmosphere of the two hemispheres at the semi-annual frequency.”
d) “When considering separately monthly averages rather than annual ones, differences in the net radiative flux distribution appear, due to the seasonal variation in insulation which is asymmetric with respect to the equator. Seasonal variations of insulation result in seasonal variations of poleward meridional transport, hence of averaged zonal wind.” [Typo: “insulation” should read “insolation”.]
e) “The argument above serves to show that the semiannual variation in lod is linked to a fundamental feature of climate: the latitudinal distribution and transport of energy and momentum.”
5. Technical Notes:
a) The Morlet wavenumber has been chosen such that average solar cycle length is ~2/3 of the Gaussian envelope. In layman’s terms, this is like adjusting a “microscope” set to semi-annual “magnification” to ~11 year “focal length”.
b) Towards the end of the wavelet power time series, there is an edge effect; the shape of gross features can be trusted, but amplitudes should be interpreted conservatively.
Data
CR:
ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/COSMIC_RAYS/STATION_DATA/
LOD:
http://www.iers.org/IERS/EN/DataProducts/EarthOrientationData/eop.html
AAM:
Hub:
http://www.aer.com/scienceResearch/diag/sb.html
Directory:
http://ftp.aer.com/pub/anon_collaborations/sba/
File:
http://ftp.aer.com/pub/anon_collaborations/sba/aam.ncep.reanalysis.1948.2009
Documentation (including references):
http://ftp.aer.com/pub/anon_collaborations/sba/readme.aam.ncep.reanalysis
Supplementary:
Monthly anomalies (which convey only interannual variation, not semi-annual):
http://www.cdc.noaa.gov/map/clim/glaam.monthly.data
QBO:
http://www.cdc.noaa.gov/data/correlation/qbo.data
SOI:
http://www.cru.uea.ac.uk/cru/data/soi/soi.dat
E.M.Smith says: December 23, 2010 at 1:32 am
“I explore the way the polar vortex might drive the ENSO and / or AO here:”
I think that the exploration of the origins and the influences of the polar vortexes definitely has merit. In particular, I have been looking into when the vortexes form and when they break up/down. If you look at page 10, Figure 8 of this paper on polar vortexes;
http://www.columbia.edu/~lmp/paps/waugh+polvani-PlumbFestVolume-2010.pdf
you’ll see an interesting chart showing the break-up dates for the Northern and Southern vortexes.
This page offers a bit of background on polar vortex breakdown and several good animations that, “depict the flow of the Polar Vortex by visualizing Potential Vorticity (a variable that acts as a tracer) over the 16-day simulation.”
http://www.vets.ucar.edu/vg/PV/index.shtml
Does anyone have/provide access to a data source that includes the historical dates when each vortex formed and broke-down? How about vortex size, shape and strength? Beyond the AO and AAO, are there are any other indexes that might serve as proxies for vortex formation and breakdown?
All ready? Now 1,2,3 and bow before the great professional scientific elite. No need to do your own thinking. Leave it to the professionals who understand everything about the sun/earth/moon/climate. Remember to keep sending your tax dollars.
Leif Svalgaard says:
Pseudo-science lives forever, no matter what the evidence.
Leif says: The shifting of air masses changes the moment of inertia and because of conservation of angular momentum we get a variation of LOD. All this is well-known and accepted.
OK, what shifts the air masses and why the semiannual variation.
utahpaw says:
December 23, 2010 at 5:57 am
One magnetic field (terrestrial) spinning in another (solar) results in drag. Change the solar field, get a change in the drag and the CR influx. Change the drag, get a change in the rotational velocity; change the rotational velocity, preserve the angular momentum via changing the (GL)AAM.
That all makes sense but why the semiannual variation?
And the really important question that is not addressed at all either in post or comment is what changes the cloud cover as the air masses shift giving rise to a change in temperature of the surface.
Without a plausible mechanism you might as well say that ENSO (the unexplainable interchange between atmosphere and ocean or some such mumbo jumbo) drives the lot.
So I am with Roger Longstaff who says: “a clear explanation of the physical process being proposed would be helpful”.
erlhapp says:
December 23, 2010 at 7:40 am
……….
Sun-Earth tilt angle?
erlhapp, No one suggested these are the only influences, just the major multi-year ones. The major semi-annual effect is probably due to changes in mass distribution (ice).
Silly me. Distance from the sun, thanks to our elliptical orbit: closer, field is stronger.
The earth’s angular momentun and LOD must drive the atmosphere, and not vice verse. So what alters the earth LOD, in roughly 10 year cycles?
.
utahpaw says:
December 23, 2010 at 5:57 am
One magnetic field (terrestrial) spinning in another (solar) results in drag.
No, not at all. There is no magnetic drag as the two fields are separated by a non-conducting atmosphere.
@Charles nelson says:
December 23, 2010 at 4:16 am
74 yr sub – harmonic lunar nodal cycle.
http://www.springerlink.com/content/t6831r104371u3j4/
North Atlantic, Effect of solar activity
http://www.climatelogic.com/book/export/html/182
Ralph says:
December 23, 2010 at 9:51 am
The earth’s angular momentun and LOD must drive the atmosphere, and not vice verse.
The Earth’s angular momentum is constant so does not drive anything. The atmosphere moves around and that changes the Earth’s moment of inertia [like an spinning ice skater moving her arms], since the angular momentum is fixed, the LOD must change [like the ice skater speeding up when drawing her arms closer http://www.hasdeu.bz.edu.ro/softuri/fizica/mariana/Mecanica/Newton_3/graphic/augumo-skater.gif ]
Thanks to Anthony for hosting this post. Thanks also to the moderation team & those who are contributing to the discussion.
–
A number of commenters may be confusing LOD & LOD’. Clear distinction is crucial to sensible conceptualization. It is the semi-annual (not multi-decadal) variations in LOD that relate to AAM variations.
–
Some have made reference to the moon. Lunisolar tides, including the LNC (lunar nodal cycle), 14 day tides, 28 day tides, & others are crystal clear in daily-resolution LOD’. There’s no ambiguity whatsoever.
The graphs of LOD’ which I have presented above have been filtered to crystallize variations on the timescale of 3 months. I encourage readers to also plot unfiltered daily LOD’ while pursuing independent data exploration. One will see the LNC clearly modulating the high-frequency variations. One will also see modulations related to polar motion. I will be investigating the preceding with increasing scrutiny when time & funding permits, particularly as these variations match patterns which I found during my very first month of climate investigations in late fall 2007. I suspect a link with seasonal (not to be confused with interannual) variations of ENSO (something which is obscured by the mainstream convention of using anomalies) and also with Arctic ice dynamics of 1988 & 2007.
–
Leif Svalgaard:
1) Daily LOD records begin in 1962.
2) As I have noted, there is a wavelet edge effect for the last few years of the record. Keep in mind that the window width [7pi] is determined by the average solar cycle length (see supplementary technical note 5a), so I’ve already pushed the boundaries a few years past conservative (hence my supplementary technical note 5b to caution other investigators — direction from an expert on wavelet edge effect management would most certainly be very welcome – alternately I will have to wait until I have more time & funding to develop methods independently).
I have been pursuing separate investigations using the annual-resolution LOD record going back to 1832. I also have on file the 1830+ LOD series with 4 month resolution (very unfortunate that the resolution isn’t 3 months). Gleaning usefully-structured information about semi-annual variation from these 2 series will be an interesting challenge, if & when time & funding permits. Perhaps an expert on aliasing will take up the challenge in the meantime.
–
I will comment further shortly.
This is an interesting short read (with references for more detail, of course):
Understanding tidal friction: A history of science in a nutshell
http://www.tribunes.com/tribune/art98/bros.htm
aul Vaughan says:
December 23, 2010 at 11:29 am
Clear distinction is crucial to sensible conceptualization. It is the semi-annual (not multi-decadal) variations in LOD that relate to AAM variations.
For multi-decadal variations you hardly need daily data.
Here is analysis of the mass balance of the atmosphere and the LOD:
ftp://ftp.csr.utexas.edu/pub/ggfc/papers/2004JB003474.pdf
Leif Svalgaard says:
December 23, 2010 at 10:26 am
Ralph says:
December 23, 2010 at 9:51 am
The earth’s angular momentun and LOD must drive the atmosphere, and not vice verse.
Leif Svalgaard says:
December 23, 2010 at 10:26 am
The Earth’s angular momentum is constant so does not drive anything.
How does the Earth’s axial wobble affect its angular momentum?
Darn, I want to read this, but “Wavelet Analysis” reminds me that I am supposed to be working and not browsing WUWT. My task for the day is to create a little stand alone class for doing some basic “Wavelet Analysis”.
Where do all you guys find the time to write up such lengthy comments?
Paul Vaughan says:
December 23, 2010 at 11:29 am
Clear distinction is crucial to sensible conceptualization. It is the semi-annual (not multi-decadal) variations in LOD that relate to AAM variations.
As you said ‘clear distinction is crucial’. Perhaps I slipped there. For the semi-annual variations you do need higher than 1-yr data, maybe 6 points per year. To make the concepts harder, I may note that the Length of the Day is about 24 hours, what is called LOD is itself a difference between the observed length and that of atomic [or ephemeris] time, so is really LOD’. You are calculating the derivative of that, i.e. LOD”, I think. In this forum details like this have to be made clear [several times: tell’em, then tell’em what you told’em].
Anyway, Figure 6 of
http://edoc.gfz-potsdam.de/gfz/get/399/0/d58d027b9a061d90d0c3919e7177485b/9603.pdf
shows the amplitude of the semiannual variation for 1985-1993.
A good analysis is here: http://www.springerlink.com/content/q02te3yjt3gy4jwu/
Paul Vaughan says:
December 23, 2010 at 11:29 am
It is the semi-annual (not multi-decadal) variations in LOD that relate to AAM variations.
Some background material:
http://www.iers.org/nn_10398/IERS/EN/Science/EarthRotation/UT1LOD.html
“The variations in LOD can be split into several components, according to their causes. The total variation is shown in the upper part of the figure, without oscillations induced by the tides of the solid Earth and oceans, are shown separately for the long and short periods. The dynamical influence of the liquid core of the earth and climatic variations in the atmosphere account for slow variations (trend in the upper part of the figure). The rest of the atmospheric excitation can be split into a seasonal oscillation and residual oscillation, which includes 50-day oscillations as well as large anomalies like the one associated with the 1983 El Niño event. ”
Click on the links in: “The variations over the recent years of UT1-TAI and in LOD are shown.”
noaaprogrammer says:
December 23, 2010 at 11:48 am
How does the Earth’s axial wobble affect its angular momentum?
Not quite sure what you mean. Try this link:
http://www.scichina.com:8081/sciAe/fileup/PDF/02ya1620.pdf
Leif Svalgaard says:
December 23, 2010 at 10:21 am
utahpaw says:
December 23, 2010 at 5:57 am
One magnetic field (terrestrial) spinning in another (solar) results in drag.
No, not at all. There is no magnetic drag as the two fields are separated by a non-conducting atmosphere.
The Earth’s magnetic field extends ten’s of thousands of kilometers in the direction of the Sun, and considerably further in the opposite direction. The atmosphere is only about 1000KM thick and is most certainly conductive, especially the ionosphere which is primarily made up of gas ionized by solar radiation. I don’t see how the atmosphere could act as a barrier between the two fields.
The terrestrial and the interplanetary magnetic fields most certainly interact, though I have no idea how much “drag” would be induced.
RSG says:
December 23, 2010 at 1:32 pm
The atmosphere is only about 1000KM thick and is most certainly conductive, especially the ionosphere which is primarily made up of gas ionized by solar radiation. I don’t see how the atmosphere could act as a barrier between the two fields.
That ionization stops below the ionosphere. The air in your living room is not ionized to any significant degree [one might hope!]. A barrier a foot thick would be enough to prevent dragging.
The terrestrial and the interplanetary magnetic fields most certainly interact
Absolute, I am one of the scientists that actually proved that [back in 1968 – the Svalgaard-Mansurov effect], but that interaction is way up in the magnetosphere.
See e.g. http://www.phys.soton.ac.uk/teach/year4/notes/phys6004/PHYS6004f9.doc
Excellent topic and information from contributors!!! I love this and give thanks to all who have researched, design equipment, collected the data, analysed the results and provided the wonderful graphs.
In one of the Vukcevic graphs , the GMF Main Field Vertical Intesity(Z), there is an convergence of the Hudson Bay, Siberia and Average that looks to be around sometime in 2004(?).
Christmas tsunami was in Dec. 2004. It was reported that this caused the LOD to increase by 2.68 microseconds. Changes in the Chandler wobble also were reported in 2005.
http://www.physorg.com/news171094752
Are these events related and caused by/to changes in angular momentum?
Seems to me that diagram 3 and 4 has peaks that relate to the cycle of shifts in atmospheric mass to the high latitudes of the winter hemisphere (dominated by the southern hemisphere peak in late year but with a sub peak for the Arctic in February-April) while the variation in the peaks is likely due to the degree of excitation of the electric currents in the atmosphere by the solar wind. This should be explicable via an examination of the relationship between the Dst index and the Arctic Oscillation and Antarctic Oscillation Indexes as I suggest here: http://climatechange1.wordpress.com/2010/12/19/the-solar-wind-shifts-in-the-atmosphere-climate-change/.
I suggest that the variation in these biennial peaks in figure 3 and 4 in this post should relate directly to the differential pressure between 30-40° and 50-60° of latitude (60-70° in the Southern Hemisphere) that drives the westerly winds in the mid latitudes and the temperature of the surface of the sea in the mid and low latitudes due to changing cloud cover associated with the flux of ozone from the winter pole.
Similarly, the variation in these peaks should relate to the northern and southern annular modes of fluctuation in geopotential heights (due to ozone flux from the winter pole and absorption of long wave radiation from the earth by ozone) that fluctuation having its greatest amplitude in the lower mesosphere upper stratosphere as described in many papers here:
http://www.nwra.com/resumes/baldwin/publications.php
but in particular this one: http://math.nyu.edu/~gerber/pages/documents/gerber_etal-JGR-2010.pdf
and in particular figure 4 in the latter paper.
Particularly interesting is the modulation of the January-February peak in the AAM from 2006 onwards corresponding with the dramatic increase in Arctic sea level pressure in winter, collapse of the westerly winds in the northern hemisphere, enhancement of the polar easterlies, the dominance of La Nina conditions in the tropics since 1997 and the return of very cold winters to the northern hemisphere.
The relationship between AAM, the SOI and the QBO (related to ozone flux and stratospheric temperature) on longer time scales is adequately demonstrated in figures 5 and 6 in Paul’s post.
This paper should excite those that insist on a whole of solar cycle response in the atmosphere: http://www.nwra.com/resumes/baldwin/pubs/LuGrayJarvisBaldwin_SH_SC_QJ_submitted.pdf
The conclusion makes interesting reading.
“In late winter to spring, the positive solar signals in mid-latitude stratospheric
zonal-mean zonal wind are shown to connect into the troposphere under wQBO but not under eQBO. Likewise, stronger vertical connection of solar signals was also reported in the NH during late winter and spring under wQBO (Lu et al. 2009). This enhanced stratosphere-troposphere coupling in late winter and spring under HS/wQBO requires an explanation and may help to understand the tropospheric SC/QBO signals. One possibility involves vertically propagating planetary waves from
the troposphere to the stratosphere and subsequent descent of zonal wind anomalies into the troposphere (Chen and Robinson 1992; Song and Robinson 2004) but the mechanisms are not well understood and it is not clear why this coupling should be most effective in wQBO years. Another possibility involves a tropospheric response to stratospheric heating anomalies (Simpson et al. 2009) which may depend on the background climatology of the stratospheric wind field and on the strength of the equatorial lower stratospheric heating anomaly, which is likely to be positive under HS/wQBO conditions. Model simulations are needed to provide a clearer explanation as it is hard to tell from the observational data how and where these tropospheric solar signals originate or whether the dominant mechanism resides primarily in the troposphere or the stratosphere.”
I am confident that the ‘tropospheric response to stratospheric heating anomalies (Simpson et al. 2009) ‘ is the link that will be fruitful because those heating anomalies in the stratosphere project downwards into the troposphere to at least 500hPa (5Km) in a mirror image of the heating anomalies in the stratosphere, impact cloud cover and sea surface temperature. And of course, the stratosphere leads.
It all starts at the winter pole. Its pathetic to consider that mainstream climate science has it all backwards, suggesting that ENSO somehow projects onto the northern and southern annular modes and that ‘planetary waves’ can be causal when we know that AAM is directly related to shifts in atmospheric mass.
In my view this is a post that defines the relationships between critical variables relating to climate. But, the explanation of how climate varies over time will involve an explanation of why and how shifts in atmospheric mass occur and acquire a bias over time. Interestingly Baldwin and associates are preoccupied with the notion that in order to explore the dynamics of the NAM and the SAM they must adjust data for the evolving bias in where the bulk of the atmosphere is located instead of asking why it shifts. That is the key.
RSG: The terrestrial and the interplanetary magnetic fields most certainly interact,
When the charged particles are accelerated in the electromagnetic medium they carry the neutrals along with them and an atmosphere that is collapsed at solar minimum and during low solar cycles is much more reactive that is highly inflated at the top of the solar cycle. It follows that the most vigorous variations in the Earths atmosphere that are due to the sun occur in shorter time scales than the 11 year cycle. These are commonly attributed to the mysterious ENSO, and the Madden Julian Oscillation that are products not causes just like the ripples on the water. The ripples don’t cause the wind. Its the wind that causes the ripples.
If we continue to be preoccupied with whole of solar cycle variations we deserve to be ‘done’ by the warmers.
Re: Leif Svalgaard
Thanks for the links — for example, the LOD decomposition graphs here might clarify a lot for readers new to LOD components:
http://www.iers.org/nn_10398/IERS/EN/Science/EarthRotation/LODplot.html?__nnn=true
The conclusion of Chen, J. (2005) is quite interesting:
“The discrepancies between observed length-of-day variations and atmospheric contributions appear more likely caused by the errors of the atmospheric models, in particular of the wind fields.”
Leif Svalgaard wrote, “For multi-decadal variations you hardly need daily data.”
Leif’s later comments suggest that he has reflected carefully and independently understood what follows, for the benefit of others:
Clarification: Le Mouël, Blanter, Shnirman, & Courtillot (2010) have studied decadal (extent) variations in semi-annual (grain) power. The research is about neither decadal nor multidecadal (grain) variations.
I realize the preceding point will strain many readers, particularly those lacking a solid conceptual foundation in advanced physical geography or a related field like landscape ecology, but it is absolutely crucial to differentiate between grain & extent in spatiotemporal analysis.
The magnification & the focal length are 2 different parameters. In wavelet lingo, the wavelength (the sampling unit) & the wavenumber (number of waves in a window) are not the same thing. It’s a sieve where not only the pore size is adjustable, but also the area of the field of pores.
This matters tremendously in pattern recognition if there is a clumping or clustering of features of some particular small size over a wider area. There are 2 scales to consider, for example the size of a human & the size of cities if one is studying the distribution of humans. The grain needs to be adjusted to focus on humans while the extent is adjusted to be capable of seeing cities.
Le Mouël, Blanter, Shnirman, & Courtillot (2010) found a clustering of 0.5 year features at 11 year intervals. Such detection requires focus not only at the right grain (0.5 years), but also at the right extent (11 years). Most other researchers were leaving the extent parameter completely out of the picture, literally ignoring it (whether due to conscious negligence or innocent naivety).
Ecologists run into absolutely endless sampling issues due to this kind of stuff. Some of them have responded by learning and fortunately those enlightened few have shared with their students.
It’s all about avoiding Simpson’s Paradox, which arises when summaries are not conditioned sensibly on key factors, such as grain & extent in spatiotemporal analysis. In exploratory spatiotemporal series analysis, one needs to roll through a range of grain & extent settings and take note of the effect on parameter estimates (unless one has sufficient intuition/understanding of the phenomenon under study to jump straight to the right settings). In the conventional mainstream, most researchers are aware of the need to roll through grain-space, but not many show awareness of the need do the same for extent – or if they do it, they do it separately instead of in concert.
If someone wants to supply funding, I can make time to illustrate the preceding points graphically at a level accessible to a mainstream audience, but readers might appreciate that this stuff is the subject of whole graduate level university courses – & life-long learning beyond that for many – so it might not always be possible to get all of the vital points across succinctly on limited volunteer hours.
Leif, it is important to note that Hopfner, J. (1996) only varied one of the parameters: grain. He did not vary extent. In layman’s terms, he didn’t adjust his microscope up & down at his chosen magnifications to vary the width of the viewing field. This would not pass in an advanced physical geography or landscape ecology course, but this is certainly not to say that Hopfner has not contributed to the multidisciplinary puzzle from his own area of expertise (quite the contrary).
tallbloke, vukcevic & others have raised some fascinating points about multidecadal variations in LOD. It is very important, however, to realize that Le Mouël, Blanter, Shnirman, & Courtillot (2010) are drawing our attention to something that is “not the same thing”. The “something else” to which they are drawing attention is occurring in the atmosphere at semi-annual timescales (and clustering at ~11 year intervals). These aren’t “competing” concepts, just different parts of a broader whole.
I include the preceding note to caution readers to not, via erroneous conflation, be accidentally/unintentionally persuaded to glaze over the results of Le Mouël, Blanter, Shnirman, & Courtillot (2010) as something “already seen, been there, done that”. Their contribution needs to be understood by as many capable people as possible, as it can play a major role in promoting wider-spread awareness of how the mainstream climate science convention of leaning too heavily on anomalies has mired both the field & the public in the relentless grip of Simpson’s Paradox. Here is another passage from Le Mouël, Blanter, Shnirman, & Courtillot (2010) that might help:
“The solid Earth behaves as a natural spatial integrator and time filter […]”
Pause to consider that carefully.
“The solid Earth behaves as a natural spatial integrator and time filter, which makes it possible to study the evolution of the amplitude of the semi-annual variation in zonal winds over a fifty-year time span. We evidence strong modulation of the amplitude of this lod spectral line by the Schwabe cycle (Figure 1a). This shows that the Sun can (directly or undirectly) influence tropospheric zonal mean-winds over decadal to multi-decadal time scales. Zonal mean-winds constitute an important element of global atmospheric circulation. If the solar cycle can influence zonal mean-winds, then it may affect other features of global climate as well […]” [Typo: “undirectly” should read “indirectly”.]
They’re saying aliasing is integrating asymmetrically (due to north-south terrestrial asymmetry). Bottom Line: Seasonal cycles vary spatiotemporally (e.g. hemispherically & on decadal timescales).
All that is needed is jet deflection. This can be achieved by something so little as pressure changes in strategic locations. A sensible avenue is to focus on changes in insolation patterns (rather than on, for example, global irradiance).
Please consider the following:
1) Figure 1c:
Meehl, G.A.; Arblaster, J.M.; Branstator, G.; & van Loon, H. (2008). A coupled air-sea response mechanism to solar forcing in the Pacific Region. Journal of Climate 21, 2883-2897.
http://www.cawcr.gov.au/staff/jma/meehl_solar_coldeventlike_2008.pdf
2) Figure 1:
Roy, I; & Haigh, J.D. (2010). Solar cycle signals in sea level pressure and sea surface temperature. Atmospheric Chemistry and Physics 10, 3147-3153.
http://www.atmos-chem-phys.org/10/3147/2010/acp-10-3147-2010.pdf
Highlight:
“A large response is found in the Pacific in boreal winter: a positive anomaly […] of up to 5 hPa […] in the Bay of Alaska […] We identify solar cycle signals in the North Pacific in 155 years of sea level pressure […] data. In SLP we find in the North Pacific a weakening of the Aleutian Low and a northward shift of the Hawaiian High in response to higher solar activity, confirming the results of previous authors using different techniques. […] This pattern is robust to the inclusion or not of the ENSO index as an independent index in the regression analysis.”
While the Northeast Pacific mode is nonstationary, it might be one of the most stationary spatial modes (look at the geography, particularly the curved mountainous coast in relation to the dominant westerly flow) and such focus might explain why statistical methods designed to detect linear relations can succeed in this area while being challenged (Simpson’s Paradox) by nonstationarity elsewhere (which requires use of complex correlation, which detects coupling switching no problem at all, while linear methods fail catastrophically).
Note that the authors appear to have arrived at a sufficient state of confidence to volunteer the following generalized conclusion:
“The SLP signal in mid-latitudes varies in phase with solar activity […]”
Their speculation about the driver:
“[…] changes in the stratosphere resulting in expansion of the Hadley cell and poleward shift of the subtropical jets […] consistent with observational studies […] which have indicated an expansion of the zonal mean Hadley cell, and poleward shift of the Ferrel cell, at solar maxima.”
Loosely speaking in layman’s terms:
It’s like waving a fire hose.
In 2 words:
Jet Deflector.
Crucial exercise: Blink between the upper & lower panels of figure 6 here:
Trenberth, K.E. (2010). Changes in precipitation with climate change.
http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/ClimateChangeWaterCycle-rev.pdf
Idealized notions of stationary climatologies & temperature anomalies are throwing mainstream efforts (or lack thereof?) to understand the hydrologic cycle off the trail of insolation (not to be confused with irradiance), pressure, & circulation. Hydrology is a function of absolutes, not anomalies. In reality, seasonal cycles are spatiotemporally nonstationary (e.g. semi-annual hemispheric circulation variation, lunisolar tides, other) and temperature/cloud/precipitation relations reverse sign seasonally over substantial portions of the globe, most notably in the northern hemisphere. Regrettably, some mainstream climate science leaders fell victim to Simpson’s Paradox decades ago; the point is not to issue blame, but rather to suggest that we help pick up the pieces now to enable more efficient data exploration moving forward.
I draw attention to this fundamentally important article:
Schwing, F.B.; Jiang, J.; & Mendelssohn, R. (2003). Coherency of multi-scale abrupt changes between the NAO, NPI, and PDO. Geophysical Research Letters 30(7), 1406. doi:10.1029/2002GL016535.
http://www.spaceweather.ac.cn/publication/jgrs/2003/Geophysical_Research_Letters/2002GL016535.pdf
Via complex correlation, a competent data explorer will easily see that Schwing, Jiang, & Mendelssohn (2003) are casting light on the tip of a massive iceberg, possibly best conceptualized as an evolving multiscale spatiotemporal coupling matrix (that can be estimated for the past from records). I’m not convinced that the audience here is ready for such nonlinear thinking, but I sincerely hope this will change. Both our society & civilization are at risk if the current mainstream culture of overly-linear “reasoning” is left unchallenged & uncorrected. I will suggest that it is the duty of responsible & capable citizens to seriously consider involving themselves in the educational effort.
The solar-forced semi-annual atmospheric component seems fairly dominant, but there are other seasonal non-atmospheric components, including some of unknown origin. These are all assessed in this paper:
Seasonal oscillations in length-of-day
http://edoc.gfz-potsdam.de/gfz/get/399/0/d58d027b9a061d90d0c3919e7177485b/9603.pdf