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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Just as a further thought on the subject, the 24 year smooth is twice Jupiter’s orbital period, and around 6/7 of Saturn’s, 2/7 Uranus’ and 1/7 Neptune’s.
My latest post shows a relationship between north magnetic pole declination and LOD. This is further support for Richard Gross’ theory that sub-crustal currents account for most of the LOD variation I think. Since the inertia involved is huge, as evidenced by the 30 year lag from solar-SSBz motion to LOD response, a 24 year smooth which takes in two full orbits of the main variable, and most of the orbit of the next biggest variable is a reasonable choice in my view. However, I acknowledge that my engineers perspective can be informed by your statisticians perspective, so I’d appreciate your response to this. I’ll post this on my blog for you to repond there, since Anthony isn’t keen for us to discuss these issues here.
Thanks
Roy and everyone – I haven’t had time to trawl through all the comments – but it is all great stuff – I would need a day to follow up all the links – but congratulations on this very open exploration.
Even the critics of Svensmark’s GCR/cloud hypothesis – for example Sloane and Wolfendale, found that 25% of cloud percentage variability could be linked to the GCR flux (despite how that was represented as debunking the theory in the media). But, my intuition tells me we are dealing with several factors. The variable solar wind has electrical as well as magnetic effects – voltages are involved, as well as pulses strong enough to clear charged particles (aerosols), then as Stephen Wilde points out (and Drew Shindell at NASA) there are chemical and heat reactions in the upper atmosphere that transfer to lower levels – most especially in the polar vortex. These can affect the jetstream. We need to think not just about percentage cloud shifts, but also spatial shifts because the ‘global warming’ heat store is not homogenous – it is located in ocean gyres and the jetstream shifts will affect the rate of heat removal.
Leif – the low pressure centres in the Atlantic and Pacific are caused by vortices that suck air upwards – warm moist air that then creates clouds in a spiral pattern – and this effectively removes heat from the ocean surface (global warming is mostly located in the upper 300m) and dumps it westward on land. That air mass has to go somewhere – and my question to meteorologists is – are the high pressure downward air flows that spiral in the opposite direction, with dry cloudless air, also connected to the up-spirals? Rather like (analogous) the magnetic loops on the Sun!
That system willl also radiate heat outward from the planet at night. The high pressure systems will allow more sunlight in and remove insulation from warm northern waters.
There is a good long term correlation between low magnetic field (from proxies) and low temperatures – over several decades. I suggest (in my book ‘Chill’) that periods of low magnetic activity cool the planet by altering the storm tracks over the oceans and that it takes centuries to recover (as from the Little Ice Age).
As to the present – there WAS a step change in cloud cover registered by the Big Bear Solar Obs and ISCCP in 2001 – a reversal of the 1980-2000 trend of 4% global cloud decrease, with 2% up and maintained to 2006 (the last data I saw). Nobody yet has an explanation for this phase-shift that I am aware of.
You can also follow the SW wave upwelling at the top of the atmosphere from the GISS FD data. It does look to be correlated with the magnetic cycle – there are pulses of extra SW to the earth surface (less reflection) at the solar cycle maximums for 1990 and 2000. This radiation flux dwarfs the computed effect of CO2 radiative forcing over the same period at about 5:1 (I don’t know enough physics to know if that RF includes a gain factor or not).
I wish I had time to put in references and links – but am very busy with the UK media circus following the Copenhagen jamboree – its been a fascinating experience watching what various editors do with my material – from the Times, the Mail and Al Jazeera – only the latter used my full text and did not alter my words, tone or meaning!
http://www.timesonline.co.uk/tol/news/environment/article6946144.ece
It is called Science or Soundbite. It is, by the way, heavily ‘edited’ – that is to say, transformed in tone and in some crucial areas of content but the new me is very much more moderate – and no bad thing for the Times!
This is the bit that is left out –
‘This conclusion is supported by recent climate shifts that run counter to model predictions. From the data on cycles I could predict that after 2007, when Arctic summer ice reached a record low, it would start to recover. It has grown by 10% each year since. The models also predicted that the high-level winds known as the jet-stream would shift north as the globe warmed. The jet-stream directs wet weather from the Atlantic and in 2007 it shifted south, bringing widespread flooding to Western Europe.
I have seen a minority report in NASA’s archives which shows that the jet-stream shifts south in cycles as the magnetic field of the sun falls and this was characteristic of the Little Ice Age. Ominously, in 2007 the field fell to an all time low and this repeated through 2008 and 2009, as did the floods. Many solar scientists point to a link between this magnetic field and climate on Earth and when the field is low, the Earth cools. During the low in the 17th century the Thames froze every winter for fifty years and summers were a wash out.’
Too scary for the Times to contemplate, but not the Daily Mail:
http://www.dailymail.co.uk/sciencetech/article-1234515/Copenhagen-climate-change-summit-The-world-COOLING-warming-says-scientist-Peter-Taylor—prepared.html
and Al Jazeera (not to be confused in the MidWest with Al Q…..) gave the best undedited coverage:
http://english.aljazeera.net/focus/climatesos/2009/12/2009124191343603151.html
These are all online articles – I have failed to penetrate the national dailies paper versions here – the left-liberals don’t want to know, and the right-wing press want business as usual and no scary cooling.
Am doing my best to get it out there! Thanks for all the help this site offers for the opening of minds and the recovery of real science.
and this bit:
No real climate scientist ever said natural causes are acting alone.
(i.e. the IPCC were setting up a false statement)
is replaced by this:
In other words . no real climate scientist ever said humans were solely to blame for global warming
(in fact – most of them have said something very close to that and the IPCC in particular)
and it is is exactly the opposite of what I said (full version and context – see below)
The last sentence slipped my notice – I meant to snip it – the full version would have been too long.
Congrats to Peter Taylor for getting his articles online with the UK papers and Al Jazeera. The debate is heating up as the earth cools.
Peter Taylor (05:54:35)
“the low pressure centres in the Atlantic and Pacific are caused by vortices that suck air upwards – warm moist air that then creates clouds in a spiral pattern – and this effectively removes heat from the ocean surface (global warming is mostly located in the upper 300m) and dumps it westward on land. That air mass has to go somewhere – and my question to meteorologists is – are the high pressure downward air flows that spiral in the opposite direction, with dry cloudless air, also connected to the up-spirals.”
Those low pressure centres are caused by oceans warming the air above which then convects upward. The spiral feature is caused by the coriolis forces in each hemisphere.
What goes up must come down so, yes, the descending air in the high pressure systems is indeed air that previously went up.
Note that as far as I can see the oceans release energy to the air which then rises. No need for a pre existing vortex to do any sucking.
That is where I depart from some sceptic positions. I don’t see how changes in the upper air can control the energy release from the oceans. The tropopause divides the atmosphere into two very different sections.
There are two processes involved. Each is separate and they mingle within the stratosphere.
Firstly the oceans release energy to the troposphere which rises into the stratosphere. Mostly a convective process but also involving some conduction, radiation and assisted by the phase changes of water.
Secondly from stratosphere to space where the process of upward energy transfer is almost entirely radiative due to the rigidly stratified layering.
The two energy transfer mechanisms meet and mingle within the stratosphere which warms or cools depending on the constantly changing balance between the two systems of energy transfer.
The temperature of the troposphere then warms or cools depending on the constantly changing balance between the rate of energy release from the oceans and the temperature of the stratosphere.
Movement within the oceans varies the rate of energy transfer from ocean to air.
The turbulence (not energy content) of the solar wind varies the rate of energy transfer from air to space.
The troposphere and stratosphere react independently to maintain equilibrium over time.
Secondl
Leif Svalgaard (12:14:23) :
Ipse Dixit (11:33:53) :
Could the solar cycle cause changes in the spectrum of solar irradiance?
It can and it does. It seems that UV and infrared change in opposite directions even if TSI is constant. These changes are not large, though.
rbateman (12:19:38) :
Ipse Dixit (11:33:53) :
There is something to be said about a shift in Solar Spectrum.
I believe it has done just that, as TSI is constrained to a very narrow range.
The atmosphere is generally opaque to the lower ranges of UV, so a drop in visible but an increase in UV would lead to a change in how Solar Energy interacts with the atmosphere and surface.
This would make for a much better topic that kicking the TSI bucket around.
FergalR (15:30:33) :
rbateman:
Less UV at minimum I believe:
“A 12-year low in solar “irradiance”: Careful measurements by several NASA spacecraft show that the sun’s brightness has dropped by 0.02% at visible wavelengths and 6% at extreme UV wavelengths since the solar minimum of 1996.” from
http://science.nasa.gov/headlines/y2009/01apr_deepsolarminimum.htm
A 6% decrease in the UV spectrum seems like a significant amount. If I had reduced my speed by 6%, I wouldn’t have gotten that speeding ticket for going 89 mph (FHP seldoms writes tickets for less than 15 mph over the limit).
So, is it true that Nitrogen is heated only by EUV? Is it also true that H2O is heated by more efficiently by UV and less efficiently by IR?
Tenuc (11:12:03) :
Keith (16:43:01) :
“[Fitzy – you suspect that the earth is tethered electromagnetically to the sun]?”
Paul Vaughan (03:02:56) :
I applaud your synthesis & pioneering research.
[…] I would say that opponents have capitalized on a lack of awareness of this.
Our ‘opponents’ capitalize on the nonsense being spouted. It is harder to take us seriously as long as we pander to such pseudo science…
Peter Taylor (05:54:35) :
I suggest (in my book ‘Chill’) that periods of low magnetic activity cool the planet by altering the storm tracks over the oceans and that it takes centuries to recover (as from the Little Ice Age).
Some time ago, several colleagues and myself published a series of ‘sun-weather’ papers about the response of storms to the passage of a solar magnetic sector boundary [crossing the heliospheric current sheet]. With time the effect died [as all sun-weather effect eventually do – this is a strong empirical finding 🙂 ]. It seems that there are still people out there pushing our ‘effect’ and that it just won’t lie down and stay quiet: http://www.ann-geophys.net/27/1/2009/angeo-27-1-2009.pdf
From their conclusion:
“It is observed that explosive cyclogenesis and major extratropical storms including wind storms tend to occur within 2–3 days of the arrival of solar wind CIRs or coronal mass ejections. This conclusion is supported by the results of statistical analysis of an extensive database of extratropical storms showing that significant sea level pressure deepenings of mid-latitude storms tend to occur within a few days of the arrival of high-speed solar wind.”
Sigh…
Bart,
Seems like you are maybe trying to relate too much of the pressure variations in cloud forming areas to the bulge. Cloud forming means saturated h2o conditions which have a much lower weight. You’re adding in h2o at 18 molecular weight versus the average (n2 o2 dominated atmosphere) of 28.8 molecular weight. Moist air weighs less, like hot air and what’s more, it is going to absorb radiant heat far better than drier air as well.
Nigel,
I’m enjoying your book but am only somewhere around the first 1/3 to 1/2 of it just past where there is discussion on CRs affecting particulate sizes which seem to brighten the cloud’s albedo a bit when smaller particles are involved?? due to increases in CRs?? That suggests it’s not just the quantity of clouds involved but also how their make up varies.
Leif,
What has the last year or two brought concerning Goode & Palle’s Earthshine results that indicated a serious albedo variation in 1997/98 from their Earthshine project? Do they still stand by their original findings? From my calculations, the total peak to peak variation of their albedo change was in the neighborhood of over 10W/m^2 for a period of time. It was also a time when there were no direct measurements being done due to equipment problems.
As for the bulge reducing pressures high up. There isn’t much up there in the way of molecules and total changes in radiation calculate out to be just a few W/m^2 at most for a co2 doubling above the tropopause. Part of this is due to the local high temperatures, some being above 300K, and the fact it is emitting rather well compared to colder Temps for that amount of material. Also, h2o and co2 and … are pretty absorber/emitters and don’t need tremendous quantities to have a more significant effect than one might assume from this.
However, a reduction in presssure would result in a narrowing of already narrow absorption lines while emissions from cloud tops, surface, and even atmosphere are going to be broader so less of the total gets absorbed. I doubt though it is significant or potentially even measureable.
CERN has an experiment called CLOUD that will try to find the connections, if any, between cosmic rays and cloud formation.
http://public.web.cern.ch/public/en/Research/CLOUD-en.html
I would like to notice that new paper to everybody:
http://cat.inist.fr/?aModele=afficheN&cpsidt=20691128
I think the geomagnetic fields are understimate by science in the climatic area.
If we take in consideration the explanation of Marcel Leroux on global air circulation and the impact in Clima, we can search more answers in that subject. Maybe the magnetic fields can add explanation the ENSO and the PDO too.
Now some think that Earth magnetic fields aren´t only protectors of the planet. Maybe that fields take energy outside the planet, especially the sun.
However we dont know very well as it does impact the global temperatures. Some say the ozono layer changes with impact of cosmic rays. And others say that layer or his hole can impact in temperatures in Antartica. So, if geomagnetic fields has relation with temperatures, in that process, at least in the poles, and if the air circulation are afected too by temperatures in the poles (as in the equador), the system is more complex than we thougth. But more simple to understand the link between low magnitc solar activity and global temperatures in Earth.
But if that brasilian team has found a direct connection between magnetic fields and tropical pacific air circulation we can´t be astonished how could be in large scale. Global large scale.
So I sugest to see to global maps. One with geomagnetic fields the other the temperatures by satelite. Like these:
http://pool.org.au/files/imagecache/full_size/image/image/Peter%20Ravenscroft/geomagnetic-field-vertical.jpg
http://ima.weather.com/images/maps/en_UK/web_intl_acttemps_world_600.jpg
Maybe the magnetic fields are more important than we think. And maybe we are neglecting something more “simple” to explain the temperatures variability.
Excuse me the spam, but as a layman in that field (my background is economics) and curious in the clima subject I allways ask the basic questions before going to more complicated questions.
One basic question I do a lot of times is: why are poles too cold? The standard answers aren´t, in my opinion, the best.
I i was and alien, outside the Earth, I could do the same question. Why are the Earth poles so cold?
North south are only positions relative to us, inhabitants of Earth. And the energy from the sun can´t explain all. Especially the diferences between the tropical temperatures and poles temperatures. Maybe more is needed to understand that clivage between so extrems in temperatures.
But, hey, Im only a layman who likes read and understand that kind of things.
cba (07:22:59) :
What has the last year or two brought concerning Goode & Palle’s Earthshine results that indicated a serious albedo variation in 1997/98 from their Earthshine project? Do they still stand by their original findings?
They are still at it, and I’m in contact with Palle. As far as I know, they are standing by the original findings, extended with more data. We have to wait and see what the newest data suggest.
PJMM (08:26:41) :
I think the geomagnetic fields are understimate by science in the climatic area.
From their paper:
“The correlation coefficient of the sea-level pressure 36-month running means versus the magnetic field intensity is 0.96.”
Computing correlation coefficients on running means is a statistical no-no, that right there causes me to put the paper aside.
“Computing correlation coefficients on running means is a statistical no-no, that right there causes me to put the paper aside.”
I see. But how they could exclude noise of data, in that samples? I mean, in some way they treat the raw data and exclude noise.
But maybe they are wrong.
Just another note. What causes the trap of the cold air inside the artic poles and later releases that air in direction of equador? Even Marcel Leroux didnt have the answer to that process.
I mean, I understand the outbreak if I use the thermodinamic process. What I dont understand is the trap of the cold. And that trap in the process, at somepoint releases the air. To me is very sugestive to look geomagnetic fields teking action in that process.
In the same way, when I think why the cold air in the poles are “traped” and why that cold can´t balance more the differential between poles and equador, I just think in magnetic fields. To me, even Im not expert in the area, I Know cold and hot are only energy. And that energy should balance more the temperatures differential between poles and equador. The only thing that I see that fits the process is taking all Earth as a magnetic body with… 3 poles! Who seems to me bizarre and strange.
Anyway, as I see the process, something happens when the sun magnetic state induces changes in the earth rotation. Changes everything. The air circulation too. In the process everything changes. Solids, liquids and gases. Changes the geomagnetic fields in our planet or even the magnetic north pole. Even in smal part. If we take in consideration all that things happening, even in small changes, maybe that explain the correlation between LOD and temperatures. And geomagnetic solar activity.
This is my humble opinion. As a layman, off course.
PJMM (10:48:09) :
Anyway, as I see the process, something happens when the sun magnetic state induces changes in the earth rotation. Changes everything. The air circulation too. In the process everything changes. Solids, liquids and gases. Changes the geomagnetic fields in our planet or even the magnetic north pole. Even in smal part. If we take in consideration all that things happening, even in small changes, maybe that explain the correlation between LOD and temperatures. And geomagnetic solar activity.
If you want to explain everything, you often end up explaining nothing. These things are very complex and interlocking and many processes are at work.
This is my humble opinion. As a layman, off course.
“If you want to explain everything, you often end up explaining nothing. These things are very complex and interlocking and many processes are at work.”
Well, I dont want to explain everything. On the contrary. To me, when the sun induces changes in the magnetic field, inside the Earth, triggers a serie of events. Thats why we see a lot of correlations in some fenomena. The cause is the sun magnetic field.
Thats why I think Courtillot and others shows us the way. They tried to open a way of thinking that was neglected a lot.
What I see is allways thinking in the energetic balance inside the system, when the debate is on. But even when we think in energetic balance we forgot to put in the discussion things that we got as settled. Like the air circulation, now the mantra of climate debates. Why is so cold in the poles and why that air is like traped there? Challenging the laws of thermodinamics? If we see the Earth as one body and his gases, why that differential in temperatures? Laws of thermodinamics don´t aplly in that fenomena? If applys, how?
As Marcel Leroux, I think were 50 years rumbling about the same things, without going nowwhere. Today, the laymen feel the pinch of that crazy debate about climate changing, and realize that thing is afecting our pockets and life, without going nowhere. And notice that were paying some scientific error or some scientific “sex of angels” debate and the “barbarians” are entering in Viena. I mean, picking ours pockets, as the politicians are doing useing that scientific error.
Marcel Leroux took a different of view of the climate problem. He realised that were traped in old way of thinking: energetic balance here, there, etc. Aeorossols, cosmic rays and so on but not thinking in changes in the air circulation patterns, for example. Not looking to the air circulation as system that could change the temperatures without externs forcings. Just changing the global air circulation we can assist to a serie of events that could trigger an climate change. Something like to shutt down the Gulfstream and trigger an Ice Age.
So, what I think is simple. When the sun induces changes in the earth because his low magnetic activity, the air circulation changes too, because the gases must change too. just like that.
The problem is, as you said, when that thing happens, a lot of processes starts changing too. Maybe even the vulcan activity changes too, giving us an explanation why may we see some cold temperatures, isnt true? Or maybe the cold air traped in poles starts to be bursted more often, with more intensity, giving us winters with more cold, because maybe is the magnetic fields that traps that cold air.
At same point, for me, is simple. But the system and the numbers of processes are so great that we cant say is simple but complex.
In the same way I saw this in economics. How much of us try to catch “the thing” that triggers a serie of the events and we dream to corner these events making a huge profit? 🙂
But what I saw is debating allways the same whitout going nowhere. Or neglecting a lot of works in the field because we dont want to look if someone gave us the shoulders, to jumping more high.
Who knows? 🙂
PJMM (12:39:08) :
Thats why I think Courtillot and others shows us the way. They tried to open a way of thinking that was neglected a lot.
I have to confess that I as peer-reviewer in the past have rejected Courtillot et al.’s work because it was of poor quality. I’m very familiar with that line of ‘inquiry’. And it has not led anywhere.
Re: tallbloke (04:54:35)
Although I applaud your openmindedness, desire & efforts to synthesize, and willingness to take pioneering risk, I have to note that I disagree [quite strongly] with some (not all) of your methods & interpretations.
Do you know where I can find monthly (&/or daily) summaries (&/or reconstructed estimates) of solar wind speed going back as far as possible in time (on a plain-text webpage)?
If you can help here, I may have something noteworthy to contribute to your blog.
Paul Vaughan (13:24:42) :
Do you know where I can find monthly (&/or daily) summaries (&/or reconstructed estimates) of solar wind speed going back as far as possible in time (on a plain-text webpage)?
The spreadsheet http://www.leif.org/research/IDV,%20B%20analysis%20-%20 rotations.xls
has my reconstruction of solar wind speed on a 27-day average basis back to 1882 [the green columns starting in row 621].
The spreadsheet http://www.leif.org/research/IDV,%20B%20analysis%20-%20rotations.xls
Henrik Svensmark did not comment in the post, at least not that I could find. I think some comments here have veered off what he has said. In fairness, some should take time to examine what Henrik Svensmark has actually said and not assume what he has said.
This is very nice.
It important to note that the total amount of cloud cover variation isn’t all there is to the story. The location of the clouds is important too. We’re not likely to see any effect over land and off shore, as there is already lots aerosols in the air. Where we are likely to see CRF effects is over large bodies of water, where albedo is usually very low. CRF changes are likely affect energy flow by much more than the signal we’d see just looking at cloud cover area alone.
CRF and geomagnetic activity are likely to affect more than just clouds. Another commenter shared a paper earlier this year that shows a correlation of solar and volcanic activity.
I can think of a couple plausible mechanisms.
“I have to confess that I as peer-reviewer in the past have rejected Courtillot et al.’s work because it was of poor quality.”
That I didnt know it. Thanks for the information. 🙂
Let me say how I did in that subject.
As a layman who only knows that in th past, solar activity was used to predict price cycles (Jevons) and opened economic cycles subject, I started with the basics. Thas why I was introduced to Courtillot and others. And I read almost all I could. Oldest and new. And Courtillot et al came to my wyes like something to look and to explain better what maybe happens.
Thanks, I should read more. 🙂
PJMM (14:51:58) :
That’s why I was introduced to Courtillot and others.
I’m sure Courtillot disagrees with my [and the other reviewer’s too] assessment. Correlations are easy to come by. Physical causation and understanding are much harder.