Spencer’s posited 1-2% cloud cover variation found

In a nutshell, with a −1.6%per decade change in cloud cover during 1954–2005, it becomes a climate forcing. While China is not the world, it bears consideration.

The Hockey Schtick reports:
New paper finds significant, natural decrease in cloudiness over past 50 years

image

A paper published last week finds that cloud cover over China significantly decreased during the period 1954-2005. This finding is in direct contradiction to the theory of man-made global warming which presumes that warming allegedly from CO2 ‘should’ cause an increase in water vapor and cloudiness. The authors also find the decrease in cloud cover was not related to man-made aerosols, and thus was likely a natural phenomenon, potentially a result of increased solar activity via the Svensmark theory or other mechanisms. As climatologist Dr. Roy Spencer has pointed out his book

The most obvious way for warming to be caused naturally is for small, natural fluctuations in the circulation patterns of the atmosphere and ocean to result in a 1% or 2% decrease in global cloud cover. Clouds are the Earth’s sunshade, and if cloud cover changes for any reason, you have global warming — or global cooling.”

Ann. Geophys., 30, 573-582, 2012

www.ann-geophys.net/30/573/2012/

doi:10.5194/angeo-30-573-2012

Significant decreasing cloud cover during 1954–2005 due to more clear-sky days and less overcast days in China and its relation to aerosol

X. Xia

LAGEO, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China

================================================================

Abstract:

An updated analysis of cloud cover during 1954–2005 in China was performed using homogeneous cloud cover data from 314 stations. Long-term changes in frequencies of different cloud cover categories and their contributions to long-term changes in cloud cover were assessed. Furthermore, aerosol effects on cloud cover trends were discussed based on comparison of cloud cover trends in polluted and mildly polluted regions. Frequencies of clear sky (cloud cover <20%) and overcast days (cloud cover >80%) were observed to increase by ~2.2 days and decrease by ~3.3 days per decade, respectively, which accounts for ~80% of cloud cover reduction. Larger decreasing trends in cloud cover due to larger increase in clear sky frequency and larger decreases in overcast frequency were observed at stations with lower aerosol optical depth. There is no significant difference in trends regarding cloud cover, clear sky frequency, and overcast frequency between mountain and plain stations. These results are inconsistent with our expectation that larger decreasing trends in cloud cover should have been observed in regions with higher aerosol loading where more aerosols could lead to stronger obscuring effect on ground observation of cloud cover and stronger radiative effect as compared with the mildly polluted regions. Aerosol effect on decreasing cloud cover in China appear not to be supported by this analysis and therefore, further study on this issue is required.

Summary:

A homogeneous cloud cover dataset in China was used to study long-term changes in cloud cover and frequencies of cloud cover categories. A simple yet effective statistical method was applied to study quantitative contributions of graded cloud cover frequency to the overall trend in cloud cover. The relationship between AOD and cloud cover trend was analyzed to discuss aerosol effects on decadal trend of cloud cover. Major conclusions follow.

Significant decline in cloud cover with trend of −1.6%per decade during 1954–2005 was derived. Occurrences of clear sky (cloud cover <20 %) and overcast days (>80 %) were observed to increase and decline by 2.2 days per decade and 3.3 days per decade, respectively. Approximately 80% of overall trend of cloud cover is attributable to an increase in clear-sky days and a decline in overcast days.

Larger decreasing cloud-amount trends have been observed due to larger increasing clear sky frequency and larger decreasing overcast frequency at stations with lower AOD.

There is not significant difference among trends of cloud cover, clear sky frequency, and overcast sky frequency between mountain and plain stations. These analyses do not

support the speculation that the decreasing trend of cloud cover in regions with higher AOD should be larger than that in mildly polluted regions due to stronger aerosol obscuring effect on ground observation of cloud cover and stronger radiative effect in polluted regions. This suggests that causes for significant decreasing trend in cloud cover in China require further study.

Link to the full paper is here: http://www.ann-geophys.net/30/573/2012/angeo-30-573-2012.pdf

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Bill

Sounds very interesting. As with most climate studies, the error bars are probably huge. -1.6% +/- what?

Solar activity was largest in the middle of the 20th century and has since basically decreased to where it is now down to what it was at the beginning of the 20th century. In spite of this, the cosmic ray intensity has not shown any trend since reliable measurements began in the early 1950s, so it would seem hard to ascribe the decrease in cloud cover to any solar variable.

DirkH

Bill says:
April 4, 2012 at 2:24 pm
“Sounds very interesting. As with most climate studies, the error bars are probably huge. -1.6% +/- what?”
They use the word “significant” several times; meaning, what they observe is unlikely to happen by chance given the expected error distribution.

mfo
TomRude

Hardly surprising: pressures have been steadily rising over the Gobi Desert in China since 1960 and temperatures have been decreasing there during the same period figure 14.47 page 382 Leroux, Dynamic Analysis of Weather and Climate 2010 Springer/Praxis. This confirms once again the insightful analysis by the late French climatologist and of course shows the increase in Mobile Polar Highs reaching deeper southward, hardly a signature of global warming…

Dale

Nature can be pretty inconvenient when it wants to.

The Other Tex

Just curious, but which measure of “solar activity” are you using to make that statement Leif? And when you state the lack of any cosmic ray trend, which measurement are you referring to? Those aren’t loaded questions, I honestly don’t know the answers and would like to be able to look at the data you are referring to. My reason for asking is because I always thought that cosmic rays were more affected by variations in the strength of the solar wind than by sunspot activity, and I wasn’t sure if there was a good dataset or set of proxies for solar wind going back that far. I also don’t know if the solar wind directly tracks sunspot activity or whether it deviates from direct correlation. With regard to cosmic ray trends, is there a long enough data set from multiple latitudes to determine if there is a difference in trend between higher and lower latitudes?

The Other Tex

With regard to the study, I would also want to see if they ruled out large scale vegetation changes due to agricultural use changes. I remember one of the Pielke’s posting a story about the “bunny fence” in Australia and what a difference the vegetation changes made in the cloud cover on each side of the fence.

These analyses do not
support the speculation that the decreasing trend of cloud cover in regions with higher AOD should be larger than that in mildly polluted regions due to stronger aerosol obscuring effect on ground observation of cloud cover and stronger radiative effect in polluted regions.

A peculiar hypothesis. Its well established that aerosols seed clouds (and its a large effect) so one would expect higher cloud cover levels where AOD is high. I’d be surprised if the obscuring ground observation effect of aerosols was larger.
Otherwise its unfortunate that they do not relate cloud cover changes to aerosol changes. I would not make the assumption that high aerosol areas are areas where aerosol levels have increased over the period of the study. Aerosol level changes in China is a complex picture with likely decreasing particulates and black carbon, while SO2/NO2 has increased.
The aerosol picture in most of the rest of the world is very different to China. So I wouldn’t draw any global conclusions from this.

jeanparisot

How will China support their indigenous work within the IPCC political circus?

Leif Svalgaard says: April 4, 2012 at 2:40 pm
“Solar activity was largest in the middle of the 20th century and has since basically decreased”
As usually, Leif trys to mislead the readers of this blog.
The truth is that there is a debate about what the sun did during the last 50 years. There is an agreement that the sun dereased its activity from 1940-1950 to 1970. From 1970 to 2000 solar acticity is claimed by PMODto have been remained constant or slighly decreased.
However the ACRIM group claims otherwise and the solar irradiance increased from 1970 to 2000, and now is decreasing.
Everything is clearly explained here
http://acrim.com/TSI%20Monitoring.htm
Leif knows very well that there exists a controversy about this issue, but he is not interested in fairly present the issues. Leif also forget to mention that PMOD composite is based on a manipulation of some satellite records. See here
http://climatechange.thinkaboutit.eu/scripts/tinymce/jscripts/tiny_mce/plugins/imagemanager/files/Kremlik/Hoyt.jpg
The above finding about a cloud cover decreasing from 1970 to 2000 due to a 60-year astronomical/solar during its warming phase is perfectly consistent with the findings of my papers where also the cloud connection is discussed. For example
N. Scafetta, “A shared frequency set between the historical mid-latitude aurora records and the global surface temperature” Journal of Atmospheric and Solar-Terrestrial Physics 74, 145-163 (2011). DOI: 10.1016/j.jastp.2011.10.013.
N. Scafetta, “Multi-scale harmonic model for solar and climate cyclical variation throughout the Holocene based on Jupiter-Saturn tidal frequencies plus the 11-year solar dynamo cycle.” Journal of Atmospheric and Solar-Terrestrial Physics in press (2012).
So, we have more data contraddicting AGW advocates and Leif.

AndyG55

http://members.optusnet.com.au/~gradds55/solar.jpg
Where does this fit in? .. seems to back Nicola’s description of heightened solar activity in the latter part of the 20th century.

Time to revisit this:
http://wattsupwiththat.com/2007/10/17/earths-albedo-tells-a-interesting-story/
This was 2007. It has further increased or remained about the same (from what I’ve found) in the meantime. The figure is key — note the relative forcing compared to the combined GHG forcing (whatever “forcing” ultimately means in a detailed balance equation). Personally, I prefer the variation in the greybody temperature, which takes into account albedo.
To Leif:
IIRC, both the solar magnetic field and the Earth’s magnetic field fluctuate, and both affect cosmic ray counts. Polar stations e.g. Oulu do show significant increases in neutron counts since e.g. the early 80’s (~25%), do they not (which is more likely to be associated with solar fields). But as the Earth’s magnetic pole wanders and the Earth’s field fluctuates, might that not modulate cosmic ray counts as well, quite possibly in tropical regions with a differential impact on climate?
Either way, whatever the cause the Earth’s albedo appears to have significantly increased over the last 15 years. Given a baseline albedo in the ballpark of 0.3, 7% is around 0.02 variation from 1997 to the present. That corresponds to roughly 2 degrees K variation in the baseline greybody temperature before the GHE goes into effect to raise it. Note also that the decrease in albedo from 1985-1986 to 1997 almost precisely corresponds to the timeframe (and, lagged, the magnitude) of the “unexplained” temperature increase of that period, the part that was attributed to climate sensitivity on top of the GHE increase (which by itself is much smaller).
This explains — or “can” explain — why even serious climate scientists might have been mistaken about climate sensitivity. The very period where the IPCC was “stimulated” by Mann’s hockey stick in 1998 on began right at the end of a period where the albedo had dropped by 10 percent! over fifteen or twenty years, a drop that was interpreted (correctly or not) as being due to climate sensitivity — an increase in atmospheric humidity and decrease in cloud cover due to increase greenhouse forcing. According to this, however, this process should continue unabated as long as GHGs increase, leading to egregious estimates of the feedback. Note that 10% corresponds to almost 3K increased forcing all by itself (but we didn’t see all of it because it is lagged by years to decades).
However, the subsequent increase in albedo by 7% (which we can also expect to be lagged by years to decades in its effect on mean temperature) is completely unexplainable in terms of this forcing model. It directly confounds the actual physical basis of the presumed high climate sensitivity, and worse — suggests that by far the majority of the late 20th century warming was due to modulation of albedo, not modulation of CO_2.
Svensmark provides an appealing hypothesis to explain why there appears to be some connection between solar state and global temperature. However, one does not need to engage in this debate to look at the albedo data and connect it to expected global temperature. Whatever the mechanism responsible for the modulation, the modulation exists, behold it. It is not only significant, it is many times larger than the expected effect resulting from anthropogenic modulation of CO_2. It is, in fact, one of the relatively few mechanisms proposed (aside from chaos and self-organization of major heat transport mechanisms) that can explain the observed variability of global temperatures over the Holocene.
In a sane Universe, physicists and climatologists would be busting their butts to understand the 10% variability in albedo, given its primary role in thermoregulation. Instead it happens, and then everybody forgets it. It is the omitted variable — one cannot even argue that it should or shouldn’t be present, and using a constant value over decadal timescales is manifestly a mistake. Garbage in, garbage out.
rgb

Finding an explanation for this 1-2% cloud cover change will only result from application of numerous hypotheses, being tested in parallel, over some goodly periods of time. My best guess, all the likely effects in some non linear and chaotic combination.

John A. Fleming

Leif says “… In spite of this, the cosmic ray intensity has not shown any trend since reliable measurements began in the early 1950s …”
Any trend is a large and unknown list. Is is just that no one has been able to find a trend so far? Has someone looked for a trend of CRI integrated over solar cycles?

John Blake

Good for Robert Brown: Whether or not researchers adduce the cause of Earth’s “significantly increased” albedo since about 1997, the fact remains that heightened reflectivity must result in a consistent cooling trend. Cloud cover, sea-ice extent, whatever… odd indeed that legions of data-junkies simply ignore a major influence on near-term global temperature conditions.

Dr. Spencer, if you haven’t seen this, you should check it out. Damped summer warming accompanied with cloud cover increase over Eurasia from 1982 to 2009 It’s a new paper out in Environmental Research Letters……
I just finished reading it and posting on my blog, when I popped my head up and see your conversation. It’s really a pretty lame paper……. they do make a huge finding though…… the areas where clouds are in the summertime correlates well with “dampened warming”. And, it seems things get hotter without them as well!!! This study was only conducted in Eurasia…… no word about how clouds would effect the rest of the world’s summertime temps. …….

Richyroo

Honest question about GCR measurements….
If GCR do catalyse cloud seed formation a la Svensmark, wouldnt they subsequently fail to reach ground based measurement locations?
Put another way, if GCR’s are ‘used up’ making clouds, would that diminnish the signal recieved at ground measurement stations?

Robert Brown says:
April 4, 2012 at 4:36 pm
Time to revisit this:
http://wattsupwiththat.com/2007/10/17/earths-albedo-tells-a-interesting-story/

The Earthshine project continues. This link has a graph up to 2008 which shows the albedo increase from around 1997 continues.
http://www.bbso.njit.edu/Research/EarthShine/
The pre-1997 decline in albedo can be explained by decreasing global anthropogenic aerosol levels (clouds seeded by them), but the post 1997 rise is something of a puzzle. A possible explanation is that while global aerosol levels were steady during this period. They increased over tropical and subtropical Asia, while decreasing at higher latitudes. Resulting in more tropical and subtropical clouds and more reflected sunlight from lower latitudes.

u.k.(us)

Don’t forget the early spring in the U.S. midwest; the trees, shrubs and plants are nearly in full bloom, one month early.
With all that shade, the ground warms slower.

Bill Illis

I think the theory expects a decrease in cloud cover.
The sunlight reflecting nature of cloud cover Albedo (about -53.0 W/m2) outweighs the back-radiation greenhouse effect of clouds (about +32.0 W/m2).
The theory is based on a feedback effect of +1.0 W/m2 per 1.0C increase in temperatures (signalling that cloud cover will decline by up to 5% given its net impact of -21.0 W/m2 even though humidity is expected to increase by 7.0% per 1.0C increase in temperatures and the climate modelers sometimes say they expect a 2.0% increase in cloud cover.
In reality, cloud cover is the make or break feedback effect. Humidity is based on the reasonably solid Classius Clayperon relation while cloud cover is just a guess at best.
If the cloud cover feedback is -1.0 W/m2/1.0C rather than +1.0 W/m2/C, then the CO2 sensitivity falls to 1.5C or so per doubling. The multiplier effect. Technically, I’ve always assumed this feedback effect has been tuned to deliver 3.0C per doubling since the climate models cannot actually determine what feedback clouds will deliver. +/- 1.0 W/m2/1.0C is a make or break factor. They picked 3.0C long ago and they are sticking with it.
(And humidity is not actually increasing according to the Classius Clayperon equations either. It is as flat as a board over the long term with the ENSO running its +/- level apparently).
http://img577.imageshack.us/img577/4600/watervapouripccvsreanal.png
http://img52.imageshack.us/img52/5716/ensotempsvstcwvnov11.png

Dr. Deanster

Lief Svalguard says: …. “Solar activity was largest in the middle of the 20th century and has since basically decreased to where it is now down to what it was at the beginning of the 20th century. In spite of this, the cosmic ray intensity has not shown any trend since reliable measurements began in the early 1950s, so it would seem hard to ascribe the decrease in cloud cover to any solar variable.”
Unless you are dealing with a “threshold” system, wherein solar activity reaches a threshold at which no more significant cosmic ray can penetrate. If such, then you’d probably have to go back further than 1950, as I recall, what was it, .. cylce 19, was the peak. Looking at the Butterfly graph of sunspot area, there appears to be a near constant intensity since cycle 18 up until cycle 24. In fact, it looks pretty flat since 1940, as cycle 18 was looks to be approximately equal in magnitude to cylces 21 and 22, and to some degree, even cycle 23. The only dwarf is cycle 20. .. and of course, cycle 24.

Paul Vaughan

Robert Brown wrote (April 4, 2012 at 4:36 pm): “In a sane Universe, physicists and climatologists would be busting their butts to understand the 10% variability in albedo, given its primary role in thermoregulation. Instead it happens, and then everybody forgets it. It is the omitted variable — one cannot even argue that it should or shouldn’t be present, and using a constant value over decadal timescales is manifestly a mistake. Garbage in, garbage out.”
Piers Corbyn (late 2011 in Germany):

Septic Matthew/Matthew R Marler

rgb: In a sane Universe, physicists and climatologists would be busting their butts to understand the 10% variability in albedo, given its primary role in thermoregulation. Instead it happens, and then everybody forgets it. It is the omitted variable — one cannot even argue that it should or shouldn’t be present, and using a constant value over decadal timescales is manifestly a mistake.
A good comment.

Paul Vaughan

Bill Illis’ (April 4, 2012 at 6:21 pm) water vapor / ENSO graph:
http://img52.imageshack.us/img52/5716/ensotempsvstcwvnov11.png
Thanks for relentlessly reminding everyone Bill.
“Apart from all other reasons, the parameters of the geoid depend on the distribution of water over the planetary surface.” — N.S. Sidorenkov

Septic Matthew/Matthew R Marler

James Sexton, from that paper: Abstract
The relationship between summer temperature, total cloud cover and precipitation over
Eurasia was investigated using observation-based products of temperature and precipitation,
and satellite-derived cloud cover and radiation products. We used a partial least squares
regression approach to separate the local influences of cloud cover and precipitation on
temperature variations. Our results suggest that the variance of summer temperature is partly
explained by changes in summer cloudiness. The summer temperature dependence on cloud
cover is strong at the high latitudes and in the middle latitude semi-humid area, while the
dependence on precipitation is strong in the Central Asia arid area and the southern Asia
humid area. During the period 1982–2009, the damped warming in extended West Siberia
accompanied with increases in cloud cover, and the pronounced warming in Europe and
Mongolia was associated with a decrease in cloud cover and precipitation. Our results suggest
that cloud cover may be the important local factor influencing the summer temperature
variation in Eurasia while precipitation plays an important role at the middle latitudes.

Much more of this sort of analysis is needed.

To many:
http://www.leif.org/research/The%20long-term%20variation%20of%20solar%20activity.pdf slide 18 [the oval] shows solar activity. Slide 29 shows that PMOD was too low lately and that there is no difference between minima in TSI. The solar microwave flux shows the same: http://www.leif.org/research/Solar-Microwaves-at-23-24-Minimum.pdf . http://www.leif.org/research/Neutron-Monitors-Real-Time.htm [last slide] look at Hermanus [the red curve] shows that there has been no trend in cosmic rays.

angelpbj

@TomRude “… pressures have been steadily rising over the Gobi Desert in China since 1960 and temperatures have been decreasing there during the same period … shows the increase in Mobile Polar Highs reaching deeper southward, hardly a signature of global warming…”
Didn’t know this, thanks for sharing.

noaaprogrammer

Richyroo asks: “If GCR do catalyse cloud seed formation a la Svensmark, wouldnt they subsequently fail to reach ground based measurement locations?
Put another way, if GCR’s are ‘used up’ making clouds, would that diminnish the signal recieved at ground measurement stations?”
No, they are not “used up.” The claim is that they leave an ionized trail of condensate.

Leif, IIRC, it was only one class of cosmic radiation that was supposed to promote cloud formation. Does the neutron monitor discriminate between different types of cosmic rays?

TomRude

@angelpbj: Thanks.
A good reading that helps understand the various observations:
http://ddata.over-blog.com/xxxyyy/2/32/25/79/Leroux-Global-and-Planetary-Change-1993.pdf

Septic Matthew/Matthew R Marler says:
April 4, 2012 at 7:33 pm
James Sexton, from that paper: Abstract
……….. Our results suggest that cloud cover may be the important local factor influencing the summer temperature variation in Eurasia while precipitation plays an important role at the middle latitudes.
Much more of this sort of analysis is needed.
=============================================================
While there is some good information in the paper, I’m not sure we needed someone to tell us summer temps are effected by cloud cover. From their conclusions…… “new evidence of strong damping
effects of daytime cloud cover on summer temperature.”

And then there’s this revelation from the press release…..“What’s more, there is a strong correlation between precipitation and cloud cover …..” http://environmentalresearchweb.org/cws/article/news/49174
I suppose I should welcome their epiphanies, but it makes me want to cry at the same time. Further, when I look at this paper on clouds/temps, and look at the referred material, there is absent names I would expect on a paper about clouds. …….. “the damped warming….”…… it’s as if they wouldn’t or couldn’t say “cooling”. Again, there is some useful information in the paper, which is why I would try to direct Dr. Spencer’s attention to it………. in many ways it complements Anthony’s gem that he came across.

“This finding is in direct contradiction to the theory of man-made global warming which presumes that warming allegedly from CO2 ‘should’ cause an increase in water vapor and cloudiness. ”
Based on this ridiculous assertion alone one can only assume you didn’t bother reading the paper or perhaps you just decided to be a little bit deceitful and ignore the section that mentioned that while cloud cover decreased over China, cloud cover increased over, hang on, I’ll just cut and paste directly so there’s no mistake…”These studies have suggested total cloud cover has increased over Europe (Henderson-Sellers, 1986), Australia (Jones and Henderson-Sellers, 1992), Canada (Milewska, 2004), the United States (Sun and Groisman, 2004; Dai et al., 2006), the Former Soviet Union (Sun and Groisman, 2000), and the northern Indian Ocean (Norris, 2001).”
Hmmm, thats a fair chunk of the rest of the world.

Analysing the sensitivity of a simple two layers model (yea with two it’s enough to get a fair approximation) for three major parameters:
– For each % increase of albedo α, surface temperature will decrease by 1.0 °C.
– For each % increase of cloudiness c, surface temperature will increase by 0.5 °C.
– For each % increase of surface emissivity ε, surface temperature will decrease by 0.8 °C.
http://bit.ly/GGZ1r2
But the major challenge is to measure an average evolution of an average cloudiness over a long time line. Temperature is already difficult enough.
Interesting is also to observe how precipitations (cloud destruction) evolve in different parts of the World: http://bit.ly/HhPyOj

Last month’s flurry of the solar CMEs resulting in a 14% Forbush decrease, appears to confirm the Svensmark’s hypothesis, with a short term fall in the cloudiness approaching 7%.
http://www.vukcevic.talktalk.net/Ap-Cl.htm

Crispin in Johannesburg

@Leif
“Solar activity was largest in the middle of the 20th century and has since basically decreased to where it is now down to what it was at the beginning of the 20th century. In spite of this, the cosmic ray intensity has not shown any trend since reliable measurements began in the early 1950s, so it would seem hard to ascribe the decrease in cloud cover to any solar variable.”
++++++++
The demonstration of the CR effect is I think undisputed, right? No one is claiming anymore that the physics are not real.
So there remain some interesting possiblities. The cloud cover change is real and we and we have two postulates on offer: the GCM’s say the cloud cover should be increasing, it is decreasing, so they are in that single respect falsified.
The heliosphere is the diverter of GCR. You mentioned CR, not GCR. Solar CR and GCR are not the same thing. Can they be differentiated? My understanding is yes, definitely. So a simple question is whether or not there has been a fluctuation in the GCR with solar activity, and similarly has there been a fluctuation in Solar CR on the same basis.
Does the heliosphere size match the ‘solar activity’ and on what basis is this connect/disconnect made? In other words what constitutes ‘solar activity’. Basic queston I know, but just covering the bases.
It is going to be pretty tough for someone to prove that CR and GCR are not causing cloud formation as the evidence is pretty clear they do and the microphysics of cloud formation is pretty well understood. If CR and GCR hitting the Earth do not affect cloud cover and are not cyclic with solar activity, we must seek another explanation for long term changes in cloud cover.

peter azlac

Robert Brown says: “
To Leif:
IIRC, both the solar magnetic field and the Earth’s magnetic field fluctuate, and both affect cosmic ray counts. Polar stations e.g. Oulu do show significant increases in neutron counts since e.g. the early 80′s (~25%), do they not (which is more likely to be associated with solar fields). But as the Earth’s magnetic pole wanders and the Earth’s field fluctuates, might that not modulate cosmic ray counts as well, quite possibly in tropical regions with a differential impact on climate?
Robert – an interesting suggestion that fits with the comments and graphics of Vukcivic on this subject. These cover the fluctuating bands of plasma that follow the magnetic field lines where the magnetic and geographic equators cross – resulting from an interaction of the sub-tropical jets with the equatorial magnetic field. http://www.vukcevic.talktalk.net/LFC20.htm At places brighter spots of plasma are concentrated, most of which are associated with thunderstorms but their positions vary with GMF flux. As vukcevic states:
“As intensity of the GMF changes with time, so it will position of the magnetic Equator (and importantly) with it location of the plasma bands. One measure of this movement is the location of equatorial crossing. The equatorial crossing has moved east-wards during the last four centuries. “
My question is whether these differences in plasma concentration along the magnetic/geographic equator offer an explanation for the differences between the studies of Lindzen and Lin concerning the “iris effect” and could this be by variable modulation of cosmic rays by this plasma belt?
http://www-eaps.mit.edu/faculty/lindzen/236-Lindzen-Choi-2011.pdf
http://trmm.chpc.utah.edu/paper/liuietiali2008ijgr.pdf

Mike says:
Based on this ridiculous assertion alone one can only assume you didn’t bother reading the paper or perhaps you just decided to be a little bit deceitful and ignore the section that mentioned that while cloud cover decreased over China, cloud cover increased over, hang on, I’ll just cut and paste directly so there’s no mistake…”These studies have suggested total cloud cover has increased…
=============================
You just quoted what OTHER papers have previously asserted, not what this paper asserts. It’s remarkable that some posters can complain about misunderstandings when they have in fact managed to confuse themselves.

Richards in Vancouver

u.k.(us) says:
April 4, 2012 at 5:36 pm
” Don’t forget the early spring in the U.S. midwest; the trees, shrubs and plants are nearly in full bloom, one month early.
With all that shade, the ground warms slower.”
Sure, but where do you start? With all that shade the preceding winter, the ground cools slower too. The nights especially are much warmer under a cloud cover.

Dario from Turin

According to the book “Canicules et glacierese – Histoire humaine ed comparèe du climat” by the French historian Emmanuel LeRoy Ladurie, during the Maunder Minimum the astronomical observations where difficult because of a persistent cloud cover, with observatories forced to work only 1 night over 3…

Kelvin Vaughan

James Sexton says:
April 4, 2012 at 11:13 pm
There is also a strong correlation between cloud cover and sun bathing!

Stephen Wilde

Poleward shifting jets and climate zones give decreased cloudiness and more energy into the oceans to skew ENSO in favour of warming El Ninos.
The opposite for equatorward shifting jets and climate zones.
Previously discussed here:
http://climaterealists.com/index.php?id=6645
“How The Sun Could Control Earth’s Temperature”
meaning variations in such temperature for someone who was pernickety about the title.

peter azlac says:
April 5, 2012 at 1:28 am
………….
Thanks for highlighting my effots.
Geomagnetic equator’s position is determined by magnetic strength of two poles and their geographic location. The ‘south’ pole is relatively strait forward, its strength is falling off at a steady rate and its movement is simple.
Variability in the North hemisphere is more complex; there is a bifurcation of the field with the ‘apparent pole’ wandering around, as the balance between two extremities changes. There is strong possibility that this balance is altered by impact of the geomagnetic storms due to the solar coronal mass ejections – the CMEs and not related to GCRs. http://www.vukcevic.talktalk.net/Tromso.htm result: the ‘north’ magnetic field intensity correlates well with the long term changes in the solar activity.
‘Speculative’ info at: http://www.vukcevic.talktalk.net/MF.htm

Leif Svalgaard says: April 4, 2012 at 2:40 pm
“Solar activity was largest in the middle of the 20th century and has since basically decreased”

Being economical with the actualite again Leif? Tut tut.
After we knock off your 20% From the period in the mid C20th you say was overcounted, and allow for the short, steep ramped cycles following, it’s easy to see that solar activity was cumulatively increasing above the long term average since 1749 all the way from ~1934 to ~2003.
Why you would wish to mislead by omission of important facts I can’t imagine.

de-lewis

The standardized method of temperature measurement (Stevenson screen) is quite sensitive to ground radiation (as readers of this site would know). One therefore needs to ask the question; would the same temperature rise be evident if the measurements were taken higher above the ground? (ie 10 or 20m). I am not implying that there’s no connection between CC and LT temperature, merely pointing out the limitations of ground based measurements.

Jimbo

Could deforestation be one of the cloud cover variation mechanisms?

As early as the 1950s deforestation in China attracted attention, but it was not until the 1960s that it assumed alarming proportions.
http://tinyurl.com/cpkx6de

Could desiccation be another?

North and northwest China, where the average annual precipitation has decreased by one third between the 1950s and the 1980s,2 has been experiencing just such a desiccation process. Evidence is clear and abundant. For example, lake Lobnor vanished in 1972, and lake Kukunor, since the beginning of Holocene period, has dwindled in area by one third and in depth by 100 m.3 Finally, the depth of lake Ohlin, at the head of the Yellow River, has been dropping by over 2 cm annually.4
http://www.library.utoronto.ca/pcs/state/chinaeco/forest.htm

Here is a model based on IPCC assumptions that states that China should expect more floods.

The significant increases of heavy rainfall ratios indicate that as the climate warms, heavy rainfall events are expected to increase at rates that are much faster than increases in total precipitation amounts, indicating that China will experience increased amounts of flooding. These results are substantially consistent among the three IPCC (Intergovernmental Panel on Climate Change) scenarios.
The increased probability of heavy rainfall events in China is closely connected with increased transportation of water vapour from the Arabian Sea and the South China Sea. Additionally, atmosphere stratification has become increasingly unstable, which has provided a favorable background for the initiation of heavy rainfall at the end of the 21st century.
http://onlinelibrary.wiley.com/doi/10.1002/joc.2278/abstract

And from the IPCC

The projected decline in rainfall over most of China is substantial in numerical experiments that include the effects of sulfate aerosols.
http://www.ipcc.ch/ipccreports/sres/regional/266.htm

Make of it what you will.

Snowlover123

I think that this paper could possibly prove the ACRIM composite to be right, and the PMOD composite to be wrong.
This paper published in 2001 shows a significant link between direct solar variations and cloud cover changes.
http://www.agu.org/pubs/crossref/2001/2000GL012659.shtml
So if Cloud Cover is decreasing, and the trend is statistically significant, couldn’t this verify the ACRIM composite which shows a statistically significant trend upward between Solar Cycle minimas over the last 30 years?

This finding is in direct contradiction to the theory of man-made global warming which presumes that warming allegedly from CO2 ‘should’ cause an increase in water vapor and cloudiness.
Why? On the other hand, higher temperatures mean that you also need much more water vapour to form clouds.

Tom_R says:
April 4, 2012 at 9:47 pm
Leif, IIRC, it was only one class of cosmic radiation that was supposed to promote cloud formation. Does the neutron monitor discriminate between different types of cosmic rays?
No, but the Earth’s magnetic field does: The low energy GCRs that are not supposed to be active do not reach lower latitudes. The high-energy GCRs are much less modulated by solar activity.
Crispin in Johannesburg says:
April 5, 2012 at 12:58 am
The demonstration of the CR effect is I think undisputed, right? No one is claiming anymore that the physics are not real.
The efficiency of the process seems much too low to have any effect. More importantly, the claimed correlations do not hold up.
The heliosphere is the diverter of GCR. You mentioned CR, not GCR. Solar CR and GCR are not the same thing.
When speaking about cosmic rays one always mean the galactic ones. The solar ones are called Solar Energetic Particles and are of much lower energy and abundance [thus should have no climate effect].
Does the heliosphere size match the ‘solar activity’ and on what basis is this connect/disconnect made? In other words what constitutes ‘solar activity’.
Short answer is ‘yes’. Solar activity is the occurrence of magnetic fields and their various side effects.
It is going to be pretty tough for someone to prove that CR and GCR are not causing cloud formation as the evidence is pretty clear they do
That is wishful thinking. The evidence is too weak to be taken seriously.
peter azlac says:
April 5, 2012 at 1:28 am
But as the Earth’s magnetic pole wanders and the Earth’s field fluctuates, might that not modulate cosmic ray counts as well, quite possibly in tropical regions with a differential impact on climate?
Yes, and that modulation is much larger than the solar modulation.
As vukcevic states:
Most of what he says is pure nonsense. [and he is proud of it…]
tallbloke says:
April 5, 2012 at 2:41 am
it’s easy to see that solar activity was cumulatively increasing above the long term average since 1749 all the way from ~1934 to ~2003.
Slide 2 of http://www.leif.org/research/SHINE-2011-The-Forgotten-Sun.pdf shows solar activity since 1840 [sunspot number, geomagnetic activity, and the magnetic field in the Heliosphere]. As you can see, activity was low broadly around 1900 and 2010 and high in between. If the Sun modulates climate in any significant way, the climate now should resemble that of the early 1900s. Does it?

I’ve had a look at hours of sun records from two data sets, in Hungary (a continental climate) and the UK (a maritime climate) and solar exposure from Australia. In all cases the units they measure, hours of sun or solar exposure, are inversely related to cloudiness.
The Hugarian data show that average daily hours of sun increased 0.02 hours a day, relative an average of 5.3 hours, over the period 1970 to 2000. The Australian data show that solar exposure increased by 0.45 MJm-2year-1 relative to an average of 17.9 MJm-2. The UK data are most interesting. They show that in the period up 1966, when temperatures were falling, hours of sun fell 0.04 hours/year. In the period up to 2000, when temperatures were rising, they increased at the same rate.
The data are not strictly equivalent but all appear to confirm that there is a positive link between temperature and cloudiness. You can see the full analysis at:
http://www.climatedata.info/Discussions/Discussions/opinions.php
…under the heading ‘Trends in cloudiness and temperature’.