Geomagnetic Forcing of Earth’s Cloud Cover During 2000-2008?
Guest post by Roy W. Spencer, Ph. D.
I’ll admit to being a skeptic when it comes to other skeptics’ opinions on the potential effects of sunspot activity on climate. Oh, it’s all very possible I suppose, but I’ve always said I’ll start believing it when someone shows a quantitative connection between variations in global cloud cover (not temperature) and geomagnetic activity.
Maybe my skepticism is because I never took astronomy in college. Or, maybe it’s because I can’t see or feel cosmic rays. They sound kind of New Age to me. After all, I can see sunlight, and I can feel infrared radiation…but cosmic rays? Some might say, “Well, Roy, you work with satellite microwave data, and you can see or feel those either!” True, but I DO have a microwave oven in my kitchen…where’s your cosmic ray oven?
Now…where was I? Oh, yeah. So, since I’ve been working with 9 years of global reflected sunlight data from the CERES instrument flying on NASA’s Terra satellite, last night I decided to take a look at some data for myself.
The results, I will admit, are at least a little intriguing.
The following plots show detrended time series of monthly running 5-month averages of (top) CERES reflected shortwave deviations from the average seasonal cycle, and (bottom) monthly running geomagnetic Ap index values from the NOAA Space Weather Prediction Center. As I understand it, the Ap index is believed to be related to the level of cosmic ray activity reaching the Earth. (I will address the reason for detrending below).
Note that there is some similarity between the two plots. If we do a scatterplot of the data (below), we get an average linear relationship of about 0.05 W per sq. meter increase in reflected sunlight per 1 unit decrease in Ap index. This is at least qualitatively consistent with a decrease in solar activity corresponding to an increase in cloud cover.
(I’ve also shown a 2nd order polynomial fit (curved line) in the above plot for those who think they see a nonlinear relationship there.)
But just how big is this linear relationship seen in the above scatterplot? From looking at a 70-year plot of Ap data (originally from David Archibald), we see that the 11-year sunspot cycle modulates the Ap index by at least 10 units. Also, there are fairly routine variations on monthly and seasonal time scales of about 10 Ap units, too (click on image to see full-size):
When the 10 Ap unit variations are multiplied by the 0.05 scale factor, it suggests about a 0.5 W per sq. meter modulation of global reflected sunlight during the 11 year solar cycle (as well as in monthly and yearly variations of geomagnetic activity). I calculate that this is a factor of 10 greater than the change in reflected sunlight that results from the 0.1% modulation of the total solar irradiance during the solar cycle.
At face value, that would mean the geomagnetic modulation of cloudiness has about 10 times the effect on the amount of sunlight absorbed by the Earth as does the solar cycle’s direct modulation of the sun’s output. It also rivals the level of forcing due to anthropogenic greenhouse gas emissions, but with way more variability from year to year and decade to decade. (Can anyone say, “natural climate variability”?)
Now, returning to the detrending of the data. The trend relationship between CERES reflected sunlight and the Ap index is of the opposite sign to that seen above. This suggests that the trend in geomagnetic activity during 2000-2008 can not explain the trend in global reflected sunlight over the same period of time. However, the ratio of the trends is very small: +0.004 Watts per sq. meter per unit Ap index, rather than -0.045. So, one can always claim that some other natural change in cloud cover is overpowering the geomagnetic modulation of cloudiness. With all kinds of climate forcings all mingled in together, it would be reasonable to expect a certain signal to emerge more clearly during some periods, and less clearly during other periods.
I also did lag correlation plots of the data (not shown), and there is no obvious lag in the correlation relationship.
All of this, of course, assumes that the observed relationship during 2000-2008 is not just by chance. There is considerable autocorrelation in the reflected sunlight and geomagnetic data, which I have made even worse by computing monthly running 5-month averages (the correlation strengths increased with averaging time). So, there are relatively few degrees of freedom in the data collected during 2000-2008, which increases the probability of getting a spurious relationship just by chance.
All of the above was done in a few hours, so it is far from definitive. But it IS enough for me to keep an open mind on the subject of solar activity affecting climate variations. As usual, I’m just poking around in the data and trying to learn something…while also stirring up some discussion (to be enjoyed on other blogs) along the way.
UPDATE (12:30 p.m. 10 December 2009)
There is a question on how other solar indices compare to the CERES reflected sunlight measurements. The following lag correlation chart shows a few of them. I’m open to suggestions on what any of it might mean.
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[quote]Interesting but doesn’t Svensmark propose low and thicker (therefore more reflective) clouds as agents of global cooling?[/quote]
Mid level clouds I believe. The big fluffy white ones. They can reflect sunlight back into space. Enough that they can _easily_ counter the warming from standard AGW models.
Higher level clouds actually absorb heat, lower clouds I think are a mixed bag, some absorb some reflect.
Anyway, check out CERN’s CLOUD experiment for ongoing developments in this area.
http://public.web.cern.ch/public/en/Research/CLOUD-en.html
I’ve updated the post with sunspot indices, at the bottom.
REPLY: Hmmm…don’t see it yet at your site, will keep checking – Anthony
Atomic Hairdryer (10:26:38) :
But paging Dr Svalgaard, or anyone that can recommend me a good textbook on solar science.
Kenneth R. Lang, The sun from Space, 2nd Ed. ISBN 978-3-540-76952
Peter V. Foukal, Solar Astrophysics, 2nd Ed. ISBN 3-527-40374-4
Dermott J. Mullan, Physics of the Sun, ISBN 978-1-4200-8307-1
are among the best.
More accessible is
Kenneth R. Lang, Sun, Earth and Sky, ISBN 3-540-58778-0
D. Ch.
The TSI instruments used for monitoring for the last 30 years have a field of view several times that of the solar disk. So, they integrate over the whole solar disk.
Dr. Spencer,
I agree with your skepticism about the links behind the sun, cloud formation, and temperature. Just because something offers a possible explanation about CO2 not being the main driver of increased temperature does not mean that alternative science is PROVEN. It is at best theoretical and while it MAY be occurring, CO2 MAY be the cause of climactic warming.
Lets not paint ourselves into a corner where we act like those that came before us, quick to find causation when only correlation is occurring. I am not sure Svenmark even has that to a large extent.
Thank you for this honest article.
I guess we will find out in a couple of years. The experiment is being done in real time on us no matter what we have to say. If we cool more than the AMO would indicate we should, or we observe more clouds than normal, then this is accordance with the GCR hypothesis. If we do not, then we have to re-examine the GCR hypothesis to see what, if anything, we may have missed. Science is about showing things that go wrong with a theory. If the theory predicts XYZ, then we do an experiment to see if XYZ happens. If it doesn’t, its back to the drawing board.
crosspatch (10:26:15)
The difference between ideology and science is that if the discovery of new evidence casts doubt on the prevailing hypothesis, then there is reasonable grounds for dismissing that hypothesis. In ideology, if such evidence is presented then it is to be censored.
The triumph of science in the modern world came about largely through Galileo, who was quite brilliant. It seems that official climatology today is at the same stage of the papacy in Galileo’s day. The notion that the earth revolved around the sun was heresy to the Church, since it took man away from the centre of the universe. Similarly, to show that co2 – actually, the small part that is anthropogenic – does not follow what the official position says it does similarly dethrones man as the centre of the climate system, and should therefore have no need to atone for his sins.
Leif Svalgaard (10:17:04) :
Have you looked at AMS (American Meteorological Society) as a source?
http://ams.allenpress.com/perlserv/?request=get-archive&issn=1520-0493
The Monthly Weather Review goes back to 1873 with some detailed summaries starting in 1880’s.
crosspatch (10:28:51) :
I would change ‘AGW verification’ to ‘AGW verification & promotion’.
It takes a lot of money to tie up the MSM.
Roy
Intriguing exploration. Your estimate of the Svensmark effect appears to be of the right magnitude to explain a major solar /cosmic ray impact on climate.
As an amateur spectator, may I encourage you to explore the impact of cosmic rays on cloud albedo variations as a function of earth’s magnetic field. See:
Earth’s Magnetic field and Climate Variability.
At Global Warming Science
This shows a very remarkable visual correlation between earth’s magnetic field and the regional temperature trends. See:
Earth’s magnetic field intensity in 2000 from the Danish Orsted satellite [http://smsc.cnes.fr/OVH/]
compared to:
global temperature change from 1978 to 2006 for the lower troposphere from satellite data. [http://climate.uah.edu/25yearbig.jpg]
He cites Daniel Johnston: “An Alternative View of Global Warming”May 2008 http://www.appinsys.com/GlobalWarming/Johnston_MagneticGW.pdf who developed a prediction model for predicting the temperature anomaly as a function of the magnetic field.
Note the OPPOSITE temperature trends near north vs south magnetic poles where the earth’s temperature trends are also largest.
Could the cosmic rays be affected not just by the magnitude of Earth’s magnetic field, but also by the vector interaction with earth’s field?
e.g., between the solar wind and the earth’s field?
or the solar magnetosphere with earth’s magneto sphere?
E.g., see Prof. Alexander who showed a correlation between precipitation or runoff and the DOUBLE 22 year solar magnetic cycle. See
Linkages between solar activity, climate predictability and water resource development, W J R Alexander, F Bailey, D B Bredenkamp, A van der Merwe and N Willemse JOURNAL OF THE SOUTH AFRICAN INSTITUTION OF CIVIL ENGINEERING, Vol 49 No 2, June 2007, Pages 32–44, Paper 659
See: Solar Wind Flow Pressure – Another Indication of Solar Downtrend?
May I recommend narrowing your analysis to look separately at the Arctic and Antarctic regions. More particularly explore the north and south magnetic pole regions, compared with the changes in the solar magnetosphere and solar wind. The Svensmark effect may be strongest near the magnetic pole regions. You may find opposite signs for trends in the Svensmark effect at North vs South poles.
See A View of Solar Magnetic Fields, The Solar Corona, and the Solar Wind in Three Dimensions, Leif Svalgaard and John M. Wilcox, Ann. Rev. Astron. Astrophys. 1978. 16:429-43; and citations
The heliospheric current sheet as solar cycle proxy
Polar Field s and Solar Cycle 24 (Observational Study) Leif Svalgaard
For further summary of solar/cosmic ray papers, see:
5.1 Cosmic Rays under
Chapter 5. Solar Variability and Climate Cycles (PDF, 648 kb) in
in Climate Change Reconsidered the 2009 NIPCC report.
Happy hunting.
magicjava (10:49:29) :
[“quote]Interesting but doesn’t Svensmark propose low and thicker (therefore more reflective) clouds as agents of global cooling?[/quote]
Mid level clouds I believe. The big fluffy white ones. They can reflect sunlight back into space. Enough that they can _easily_ counter the warming from standard AGW models.
Higher level clouds actually absorb heat, lower clouds I think are a mixed bag, some absorb some reflect.”
its pure speculation on my part, so need correction from those who know better but: Precipitation is increasing everywhere, and cumulonimbus clouds are quite high (rainstorm clouds) whilst lower strata clouds give drizzle. Coupled with a solar minimum, we have increased precipitation.
rbateman (11:12:26) :
Have you looked at AMS (American Meteorological Society) as a source?
No, I think it is the enthusiasts that have to go looking, then come back with what they found…
Atomic Hairdryer (10:26:38) :
But paging Dr Svalgaard, or anyone that can recommend me a good textbook on solar science.
I’ll hazard a guess that the recommendations by Leif Svalgaard are better than the one I’ll recommend, but I’ll recommend it anyway: Plasma Physics For Astrophysics by Russell Kulsrud, published by Princeton Press.
Both the solar wind and cosmic rays are forms of plasma and both are covered in the book I mentioned.
The key idea behind this, as I see it, is the clouds. Regardless of whether or not it proven cosmic rays help form clouds, it’s the clouds themselves that affect the climate. The cosmic rays don’t change the climate directly.
I would think that the majority of people here are not PH.D’s in the science of Climate Change . While this website may be dedicated to that science , this website among others have had a influx of inquiries of a concerned public relating to ClimateGate .
Your explanation and tutoring above , which I like to call ” ClimateChange 101 ” is giving the public a better understanding of the science .
While I had read what you had presented , I really don’t have a idea on what your talking about . If I gave you instructions on how to replace a fuel injector on your vehicle’s engine you would have an idea of it but would probably pay me to do it .
The point here is that Climate Change Scientists and Apprentices are trained and familiar with shortwave deviations , scatterplots , polynomial fits , Ap unit variations and geomagnetic modulations whereas a typical person such as myself can only have a concept of your explanation above without actually being capable of executing such complex calculations . It’s a Science that is left to the ones who have a passion and devotion of it .
As with your comment in another article that ” this is not how the IPCC thinks nature works ” relating to Negitive and Positive cloud feedback , I am a Skeptic of not only the Anthropological Global Warming Theory , but of most of the research that the Goddard Institute for Space Studies and the University of East Anglia’s Hadley Climate Research Unit are involved with due mainly to , yup , the ClimateGate files .
I enjoyed your article ” A Layman’s Explanation of Why Global Warming Predictions by Climate Models are Wrong ” . . . and it seems the folks over at the University of East Anglia’s Hadley Climate Research Unit was messing with the flame under the pot of water while they were computing their measurements .
In the september 2009 article on Roy’s website:
http://www.drroyspencer.com/2009/09/the-2007-2008-global-cooling-event-evidence-for-clouds-as-the-cause/
he shows the un-detrended CERES SW+LW data which seems to show a decrease in the net energy escaping from Earth. :
http://www.drroyspencer.com/wp-content/uploads/Terra-CERES-LW-SW.jpg
The Earthshine project
http://www.bbso.njit.edu/Research/EarthShine/
shows an increase in cloudiness at the end of ’98 and continuing high levels of albedo:
http://www.bbso.njit.edu/Research/EarthShine/index_ES_Project_files/image006.jpg
Caption: Earthshine changes in albedo shown in blue, ISCCP-FD shown in black and CERES in red. A climatologically significant change before CERES followed by a long period of insignificant change.
Could Roy comment on the relationship between these other cloud measuring datasets and the CERES dataset please.
Perhaps the changes post 2000 are less significant than the increase Earthshine data shows in the couple of previous years. A significant increase in Albedo from late ’98 seems to have led to the situation where cloud is trapping energy in, more than the increase in the reflection of sunlight is having a cooling effect, and yet the global average temperature has been flat or slightly falling since ’98, just before the big el nino.
It may be that there’s another factor I’ve missed, but there seems to be some contradictions here. Maybe the Earth just isn’t getting ‘microwaved’ by magnetism as much since the Ap index fell. :o)
Regarding Svensmark’s theory and supporting data, here is a good review coupled with a briefing on the experiments (Cloud) being conducted at CERN by the lead scientist at CERN, Jasper Kirkby:
http://indico.cern.ch/getFile.py/access?resId=0&materialId=slides&confId=52576
You can also find his talk as a recorded video on the Internet. The above link is a pdf of the video presentation and gives one the opportunity to study the graphs and charts.
Actually, you can “see” cosmic rays (or rather their byproducts) when you are the ISS. When a muon goes through the right area of your skull it causes a flash of light in you visible field.
P Wilson (11:19:05)
in a warming world, there would be more high level rainstorm clouds presumable, since hot air would cause vapour to elevate more rapidly. Over here (London UK) we get much more prolonged drizzle than rain storms thesdays
” If clouds modulated SSTs, then this would be the opposite of what you would expect, wouldn’t it”
Think of tying a single rope to a bull in a china shop.
To save buying an expensive textbook, I’ll sum up the basics of Svensmark’s ideas, as I understand them.
1) Cosmic Rays are poorly named. They’re not photons like X-Rays and Gamma rays. Instead, they’re atomic nuclei without electrons, and they move at nearly the speed of light.
2) When Cosmic Rays crash into the Earth’s atmosphere they have enough energy to create Muons, which are basically giant Electrons.
3) These Muons survive long enough to act as the seeds around which water droplets can eventually form, and from there, clouds.
I can’t see or feel cosmic rays. They sound kind of New Age to me.
Don’t you?…just watch your face every morning in your bathroom’s mirror, year after year.Cosmic rays are 90% protons=hydrogen nucleii, powerful reducers.
Have you wonder why human life length is aboout that of the Gleissberg cycle?
Dr. Spencer,
Has anyone looked into the interconnection of the ionosphere and the the tropical thunder storm zone. Speculation that when earth directed CME or flares will interact with the ionosphere and troposphere to create very low RF and interfere with cloud forming nuclie. Meaning that when CME and Flare activity is high we have less clouds and when lower activity we have more clouds in the tropics. Since magnetic activity is low and also we have a very low Gauss readings for sun spots then flares and CME will be weaker this cycle. This should mean more cloud cover for this cycle and lower temperatures over all. Higher the cycle the more intense CME and Flare activity equates to less clouds. Thank you for your time.
Leif Svalgaard (11:21:03) :
rbateman (11:12:26) :
Have you looked at AMS (American Meteorological Society) as a source?
No, I think it is the enthusiasts that have to go looking, then come back with what they found…
They already did. One of them wears a Nobel and owns an Oscar.
Leif Svalgaard (10:54:42) :
Roy Spencer (11:00:54) :
It’s indeed a pleasure to be a “fly on the wall” during a discussion between the greatest scientists of our time. Thank you. Did you see the presentation of Jasper Kirkby?
http://seekingalpha.com/article/175641-climategate-revolt-of-the-physicists
As far as I understand Kirkby does not argue that a possible relationship between cosmic rays and clouds is in any way uniform – different qualitative and quantitative phenomena may take place over the land and the oceans, the equatorial regions and the polar regions.
What is the chance that we may achieve a solid understanding of the cosmic ray cloud connection if this relationship is highly non-uniform and non-trivial?
I’m still being mentally exercised by this finding:
http://earthobservatory.nasa.gov/Newsroom/view.php?id=36301
“Sunspots unleash solar flares that create a ripple effect well beyond Earth. But when that energy flow does reach Earth, the atmosphere reciprocates by ejecting radiation as a cooling effect to maintain the planet’s energy balance. That cooling response creates the expansion and contraction of the upper atmosphere.”
The implication being that the stratosphere and upper levels of the atmosphere lose energy faster to space when the solar wind is more turbulent.
Comments from Roy and Leif would be especially welcome.