Guest post by Guillermo Gonzalez
I recently happened upon the SORCE/TIM website and decided to look up the plot of the full total solar irradiance (TSI) dataset (http://lasp.colorado.edu/sorce/data/tsi_data.htm#plots)
The SORCE mission began collecting TSI data in February 2003.
I was curious to see if the variations in the TSI had begun to rise yet, perhaps indicating a start to cycle 24. Visual inspection of the SORCE TSI plot showed just the opposite – variations continue to decline in amplitude. If cycle 24 has started, there are no signs of it in these data.
We can be a bit more quantitative if we examine, instead, a plot of TSI variance with time. I produced such a plot using the daily average TSI data provided on the SORCE web site.
The red data are variance values calculated at two-week intervals. The blue curve is the smoothed data calculated in the same way as smoothed sunspot numbers (basically a 12-month running average). Note, the vertical axis is plotted on a logarithmic scale.
To compare the recent TSI variance trend with the previous sunspot minimum, I looked up the ACRIM2 daily average TSI data at: http://www.acrim.com/Data%20Products.htm
These data are plotted on the same scale as the SORCE data. The smoothed data show a minimum TSI variance near the beginning of 1996, some months before sunspot minimum (October 1996). Notice that the minimum value for the variance during the 1996 minimum was about an order of magnitude larger than the present TSI variance.
The SORCE web site quotes long-term 1-sigma precision (relative accuracy) of their TSI measurements to be 0.001%/yr. This corresponds to a variance of 2 ´ 10-4 W2 m-4. However, the precision should be considerably better than this on the 2-week timescale that I selected for calculating the variance. Unfortunately, I have not been able to locate a quote for the estimated precision of the ACRIM2 measurements. It would be worthwhile to know if the minimum TSI variance of the previous sunspot minimum measured by ACRIM2needs to be corrected for the instrumental precision.
Guillermo Gonzalez writes on his background:
I’m an astronomer, though my present title is associate professor of physics at Grove City College, PA. I wrote a paper (in Solar Physics) with Ken Schatten back in 1987 on predicting the next solar maximum with geomagnetic indices. That was my only contribution on anything having to do with the Sun-Earth connection, but I also got a letter published in Physics Today in 1997 wherein I urged readers to takethe Sun-Earth climate connection more seriously.
These days most of my research is on extrasolar planets.
UPDATE: I received a suggestion for an overlay via email from Terry Dunleavy and I’ve worked one up below. This was done graphically. I took great care to get the two lined up correctly. Note however that the datasets span different lengths of time, as you can note on the two timescales I’ve included on the combined graph. The vertical scale matches exactly between graphs though. – Anthony
UPDATE2: Here is another graphical comparison of the two TSI variance graphs, scaled to have a matching X-axis and appropriately aligned side by side. – Anthony
John Finn (17:25:56) :
I think I must be missing something. TSI appears to be about 0.05% lower than it was 5 years ago – and this is supposed to cool the climate. How exactly?
Insulation? Those of us who live in cool climates insulate our houses to save energy and preserve indoor heat. Those who live in tropical climates sometimes “dress the heat out”. It is all about insulation.
The clouds insulate the ground from the rays of the sun, by reflecting the radiation back into space. With a constant TSI but varying cloud coverage the effect will be a varying climate.
We know that the sun’s magnetic field varies much more than TSI. If Svensmark is right about magnetic fields, GCR and cloud coverage …. ?
The reader is now warned to put down your coffee before reading this PRESS RELEASE: Wednesday, October 20, 2004
Got that 2004?
One David Hathaway mentions 2010 as cycle 24 solar max. (I am not poking fun, is hard to deal with the unknown, but nevertheless is amusing in hindsight)
“Something strange happened on the sun last week: all the sunspots vanished. This is a sign, say scientists, that solar minimum is coming sooner than expected.
October 18, 2004: Six … long … years.”
This puts a different complexion on the *entire* SORCE dataset as showing the sun in an abnormal state. (in case you missed the quotes, is my comment)
http://www.spaceref.com/news/viewpr.html?pid=15318
Last significant peak of SC23 was in 2002.25 year, or 7.08 years ago. If we go back to the corresponding peak of SC22 it was in 1991.58.
If one wishes to be utterly simplistic, it follows the present time in the sunspot cycle, all being equal, should be roughly same as 1998.66 when monthly smoothed SSN was 68 or actual SSN=92.
In short: If SC24 was a near-repeat of SC23 then we should now have SSN at least 60+.
If we take SC23max about 120 and assume predicted SC24max about 70 then present SSN should have been about 40.
>>So, given that the oceans have a vastly greater heat capacity
>>than the atmosphere, does anyone know what the “damping”
>>effect (lag) may be on temperature/climate?.
Prof Landscheidt says 7 or 8 years.
.
Back in August 2005 I posted on Climate Audit to the effect that recreationally, I had used cross-semivariograms from geostatistics to examine a number of effects, fun work from the 1970s.
See http://www.climateaudit.org/?p=320
More fully, I was interested in variables with an annual time base, to reduce autocorrelation, so I hunted through journals like “Scientific American” for long annual time series than digitised them. The longest time series was the sunspot count, so I correlatated it with anything I could find that was reported for 50 years or more. There were measures for the fur trade of the Hudson’s Bay Company, the yield of tomatoes in California, the copper price on the NY stock exchange, American employment, USA GNP per capita and several others that I have now forgotten.
The rationale was that in indirect ways many of these are connected, albeit indirectly and with lags, with sunlight. More light gives better crops, more trade, more prosperity, more production of other commodities. Of course, confounding factors abound.
If it has not been done and published, I think it would be a fascinating exercise to repeat using mathematicians’ statistics of today and including more recent data.
In my quick and crude fun analysis, I was surprised by the number of above factors that appeared correlated, some of them rather well. But then, it might have been conceptually and mathematically flawed. Correlation is not causation.
My present thoughts are that if there is a connection between solar irradiance and earth temperature, it will show out in some of these indirect measures. A cold climate might equate with a cold economy, that type of expression.
1. Maybe not feedback, but the climate is a chaotic system and linear or pseudo- linea mathmatics don’t necessarily apply.
2. Although the TSI change is small what about the far-extreme UV? This changes significantly more tha the visible part of the spectrum. Increase in energy deposited in the outermost region of the atmosphere surely reduces the effectiive temperatue gagdient across it (already non-linear) and so ultimately affects the heat treansfer from surface to outer space.
3.Can we see a plot of XUV radiation vs time over several solar cyvles?
Tim Channon (04:12:37) :
From that linked press release:
“Hathaway is an expert forecaster of the solar cycle. He keeps track of sunspot numbers (the best known indicator of solar activity) and predicts years in advance when the next peaks and valleys will come.”
Yup.
And…
“But researchers are making progress. Hathaway and colleague Bob Wilson, both working at NASA’s Marshall Space Flight Center, believe they’ve found a simple way to predict the date of the next solar minimum. “We examined data from the last 8 solar cycles and discovered that Solar Min follows the first spotless day after Solar Max by 34 months,” explains Hathaway.
The most recent solar maximum was in late 2000. The first spotless day after that was Jan 28, 2004. So, using Hathaway and Wilson’s simple rule, solar minimum should arrive in late 2006. That’s about a year earlier than previously thought. ”
Heh.
One of the joys of a bibliophile is stumbling across passages like this: the past is prologue.
These two phrases caught my attention :
“”that tranquil eye which knoweth not envy”.”
“the copper brute with the firey face covered with black pimples.”
No “black pimples” today?
…-
“Notes From An African Diary*
In Africa I learned why those Scythian tribesmen, whose habits are recorded by Julian,
reserved their sharpest arrows to shoot at the sun.
To Julian, who was a sun worshipper, that was sacrilege.
Had I possessed a long-range gun on the journey to Lake Chad in the late summer of 1934,
I would willingly have sent a charge into “that tranquil eye which knoweth not envy”.
In Africa I hated the sun with an impotent fury, the fury that made Giovanni Papini,
before his conversion, speak of “the copper brute with the firey face covered with black pimples.”
On the spur of the moment, Youssef ibn Avrahim and I invented epithets even more expressive of our
helpless rage.”
*Pierre van Paasen
Days of Our Years
1903-1939
I also decided to check out the latest NASA press release:
http://www.nasa.gov/topics/solarsystem/features/solar_minimum09.html
and found this…
“Modern technology cannot, however, predict what comes next. Competing models by dozens of solar physicists disagree, sometimes sharply, on when this solar minimum will end and how big the next solar maximum will be. The great uncertainty stems from one simple fact: No one fully understands the underlying physics of the sunspot cycle.
Pesnell believes sunspot counts should pick up again soon, “possibly by the end of the year,” to be followed by a solar maximum of below-average intensity in 2012 or 2013.”
I believe the statements “Modern technology cannot, however, predict what comes next.” and “No one fully understands the underlying physics of…” can aptly be applied to other areas of science e.g. numerical climate modeling…
MA (04:04:36) :
anna v (22:32:17) : “I still think that we are dealing with a chaotic system…”
Have anyone ever opposed that?
Everyone who thinks that a direct cause:effect can be found concentrating on one of the input variables.
“In such systems it is possible for small changes to induce large effects”
And that means that we must prepare for that the butterfly CO2 can induce large effects, and don’t bother that much about the elephants in the room?
I was actually thinking of the small effect of TSI changes over the sun cycle as a small input. I consider that it is already demonstrated on this blog that the CO2 effect is irrelevant. H2O now, is another question. Though the perfect analogue chaotic model would include everything.
Wouldn’t it be possible for changes in albedo, that is clouds, during the seasonal change in TSI on the one year cycle(from January to July and back) to give the sort of climate sensitivity necessary to explain the variation in climate? Any potential instability from such a mechanism would be damped within months as the earth’s distance from the sun changed back.
==============================================
Bruce Armour (01:25:54) :
This article is interesting Bruce!
http://www.berkeley.edu/news/media/releases/2009/04/23_keiling.shtml
Leif Svalgaard (22:18:28) :
Justin Sane (21:39:34) :
Why does the 12 month running average not go to the end of the data? Shouldn’t the 12 month running average be the current month and the last 11 months rather than the 12 months ending roughly 11-12 months earlier?
No, that is not a good way of running the average. The running average should be plotted at the time of the midpoint.
Look at it this way. Take a series that has steadily trended downward for some time. Using a 12 month average to the latest figure shows the moving average trending down to the present. But suppose at just this point in time the series turns back up and begins to steadily trend upwards. Once another 6 months of data are in, you find that a 12 month average at this point in time was higher than what you were showing using an average that came to the present. So using the endpoint resulted in a lower 12 month average than actually the case.
With a moving average, you want data on either side of the current point.
For once, I agree with Leif. 😉
BTW, I’m sure there is too much cyclomania in it for Leif’s taste, but I found the Komitov paper linked to by “Just Want Truth…” to be an interesting read.
http://www.astro.bas.bg/AIJ/issues/n9/BKomitov.pdf
For those who have never seen this video on space weather/cosmoclimatology I’ll post the link once more :
Also :
http://www.google.com/hostednews/afp/article/ALeqM5h2eLthVbBG2KB428zgeirvoWrHIw
and
http://motls.blogspot.com/2009/01/stalactites-support-cosmoclimatology.html
I know this is just coincidence but my back is broad enough!
October 2007, step drop function appeared to occur in Solar output, Leif said it wasn’t unusual.
January 2008, global temps plummet 0.6°C or thereabouts. Worst winters in 20-30 years in northern hemisphere.
Solar Cycle 23 just won’t stop but keeps dragging out, Cycle 24 can’t get going. Nobody seems to have much of a real cluse when SC24 will start they keep extending the start dates every 6 months or so. When it does start it’s a damp squib!
Lousey summer weather in UK. Met Office says winter 08/09 will be as mild or milder than previous winters. Arctic summer melt didn’t break records & starts showing possible recovery. Stupid Brit half-wits keep trying to sail, canoe, walk to NP to prove it’s all melted, but keep running into ice that shouldn’t be there according to the warmists, genuine & disingenuine alike!
First October snows in 2008 for 75 years whilst UK government debates climate change bill. Coldest start to winter in UK for November for 20-30 years. 2009 coldest winter for 20 -30 years. All this is entirely in keeping with the Met Office’s understanding of Climate Change. Northern hemisphere winters significnatly colder than usual, or for around 30 years. 2009 globally cooler than 2008, 07, 06, 05 ,etc. Extended La Ninas, PDO shifts to cool phase, AMO shifts to cool phase.
Antarctic sea-ice at greatest recorded extent. Temps in Antarctica cooler. Whether it warms or cools in Antarctica it’s still in keeping with climate models as evidence of AGW.
Longest period for lack of Sunspots for almost 100 years since 1913. Cold weather records still being set on north American continent. Snows falling in the most unlikely places for the first time in living memory, or long periods of absence over 2007-2009.
Sun’s magnetic field output at 50 year low since records began.
Prof Mike Lockwood says no respite from AGW by Sun’s low output. (Expect to see hurried paper published showing Sun’s output has no effect on global climate whatsoever, never has done, never will, a best fit curve exercise.)
Surely one of these self-opinionated, two-faced, sanctimonious, duplicitous, nose in the trough taxpayer funded politicans somewhere around the world would ask the question whether if there isn’t something in it?
BTW I’m no expert but shouldn’t that period be the Suess Cycle @ur momisugly c200years whereas the notional 88 year periodicity is the gleissberg cycle?
This will be buried in the noise but it seems to be relevant to the topic. Some people claim that small changes in TSI or sunspots for that matter cannot result in larger fluctuations in the climate. Now, maybe that is correct but I see a very similar effect with low pressure discharge plasmas everyday at work. I’ll explain briefly and you can make up your own minds.
First of all the Earth is receiving over 1300 W/m2 from the Sun everyday and this heat has been distributed into the oceans and land, though predominantly in the oceans. This has been going on for millenia and there is evidence of changes in the cycle, due to some factors, in the geological record. So we can assume that the ocean current circulation and atmospheric cycles leading to weather and climate patterns are a way to distribute the heat around and that these are not quite linear but have a non-linear complex nature.
Okay, so now to the plasmas: In low pressure discharge plasmas (like Xenon or Argon singly charged plasmas) there is a well known phenomenon where drift waves, or acoustic wave appear and how a very small change in the input power characteristics causes this. To put this in perpective, in some types of discharge (Kaufman type) a critical parameter is the anode voltage (Kaufman discharges have an internal plasma circuit: cathode and anode). The anode voltage directly relates to the space charge in the discharge and to the plasma potential. Kaufman discharge space charge i.e. the amount of ionisation, is controlled by varying the amount of electrons (anode current) or the time they spend in the discharge (magnet current) for a given gas flow rate. This can also be changed to increase the ionisation range.
What happens at acoustic wave onset is that the anode voltage starts with a ‘white’ noise frequency spectrum and within a small change of the magnet current (typically below 5%, which is a much smaller increase in discharge power, maybe 1%) suddenly starts oscillating at an acoustic frequency related to the electron temperature in the plasma and the size of the discharge chamber. The onset occurs very quickly, but the overall plasma energy is hardly affected, just redistributed into coherent anode voltage oscillation. The key is that the white noise can be 0.5 V peak to peak, but the acoustic oscillation is 2 volts peak to peak or more and occuring in the kHz range.
I have produced the effect in the lab and its just a transition state in the discharge; there is nothing harmful occuring to the chamber.
The basic point though is that a small change in input power causes a large change in behaviour because the ions in the plasma start to vibrate coherently and can no longer maintain the broadband energy to oscillate as a background. Hence acoustic waves appear.
So it the ocean circulation is coupled to the physical geometry of the Earth and there are certain resonances then this redistribution of frequencies and hence changes in climate due to small changes in the sun is perfectly feasable. An additional part is that, again using the example of plasmas, if there is a frequency in the input power it does not have to be an exact fundamental frequency of the discharge to produce acoustic oscillation but only has to have an associated coupling factor. Interestingly, longer oscillations can be excited by shorter oscillations and vice versa. Hence for example El Nino could be excited by much longer oscillations in the TSI ro maybe sunspots.
If there is a sun-earth coupling then obviously is complicated and non-linear but to say that such an effect is not feasable in nature doesn’t reflect the case in plasmas where it is easily reproducable.
Thanks for the SORCE data report by Guillermo Gonzalez
When I went to the SORCE website a few weeks ago to check the TSI data and compare it to prior VIRGO satellite data, I found a major gap in the baseline between the VIRGO and SORCE TIM instrument data.
Then I came across this note on the SORCE website:
“Special Note on TIM (Total Irradiance Monitor) TSI Data
“”The TIM measures TSI values 4.7 W/m2 lower than the VIRGO and 5.1 W/m2 lower than ACRIM III.””
http://lasp.colorado.edu/cgi-bin/ion-p?page=input_data_for_tsi.ion#note
WOW! That’s a major difference and makes me question all prior non-SORCE/TIM data and their use in global warming models.
That difference is much larger than the 1 W/m2 variance between the solar cycles as measured by the older VIRGO TSI instruments.
If you go to the VIRGO site there is a page long, mind numbing, description of how they cobblel together data from different instruments using mathematical hammers to achieve the “final” TSI .. … Level 0 to Level 1, then Level 1 to Level 1.8, and finally from Level 1.8 to Level 2.0.
http://www.pmodwrc.ch/pmod.php?topic=tsi/virgo/proj_space_virgo#Data
Clearly TIM is simpler in design, more accurate, and provides direct TSI measurement.
A meeting in May 16, 2006 reviewed the different TSI instruments, but did not come to a conclusion rating one over the other. Open admittance that prior measurements are not as accurate as portrayed is a very sensitive scientific/political issue and silence appears safer than open debate.
TIM is the instrument of choice for future NASA flights.
I received this note from
Greg Kopp -TIM Instrument Scientist Laboratory for Atmospheric and Space Physics
“We have been working with the TSI community on resolving these differences, starting with a NASA-organized community workshop at NIST a couple of years ago.
Since then, we have built a new facility to calibrate TSI radiometers against a NIST-calibrated cryogenic radiometer prior to flight, and have used this facility to validate the performance of the next TIM, which will launch in early 2010 on NASA’s Glory mission. Prior to the Glory/TIM, no flight TSI instrument has been validated end-to-end for irradiance under flight-like operating conditions.”
I don’t have much to add, I read other than thanks Guillermo, Anthony and Lief for the post and replies. Educational as always.
Jeff
John F. Hultquist (21:06:50) :
The Livingston & Penn paper doesn’t really connect to this thread. It talks about a weakening of the magnetic fields around in in sunspots that has been ongoing for more than a 11-year solar cycle, this thread concerns itself with effects involving the whole sun.
Quick summary, but without referring back to L&P:
visible
Typical sunspot. Dark spot on the sun visible with a decent telescope or unmagnified viewing. (Both with appropriate filtering, of course.) The dark color is not black, it’s just an area of cooler plasma that radiates less light.
invisible
Area on the sun where the plasma is not cool but where the magnetic field shows there is a sunspot. I beleive the magnetic field is determined by looking at both polarization of light and “line splitting” where spectral lines are modified by magnetic fields in the area.
gone (not there)
Area that no longer has the magnetic signature. (It won’t have the visible signature either).
not gone but invisible
Area where the magnetic field has weakened enough to allow enough convection to allow the plasma temperature at the surface warm up so it no longer looks dark.
disappear
Have to check the context. If it’s “spots will disappear by 2015” then it means sunspot magnetic fields will be too weak to let any spot become visible.
TSI
Total Solar Iradience. Usually expressed as the total watts of all electomagnetic radiation (light including IR and UV), radio – anything that warms up an absorbing target – passing through a square meter of the top of our atmosphere (or perhaps now the altitude of the satellites that measure TSI).
A better analogy might be a dimmer switch dimming the surface of the sun, strong magnetic fields mean strong dimmer. The idea that somthing is covering the sun is not what’s going on.
No one knows. The main reason Science rejected the paper was that it didn’t propose a mechanism, it was just a statisical look at the interesting observations and wasn’t interesting enough for Science. It’s almost certain that this has happened in the past, but we didn’t have our current tools to observe the magnetic field part. My gut feeling is that the Dalton Minimum was just a period with weak cycles, but this might have happened during the Maunder Minimum. Check back in 70 years or so, we’ll have a much better idea of how the pieces fit.
——
OT:
Record heat in New England yesterday. I don’t see a nice table, but http://www.erh.noaa.gov/box/recordbreaking.shtml lists sites Boston MA, Bridgeport CT, Hartford CT, Providence RI, Worcester MA, Albany NY, Burlington VT, Portland ME, Caribou ME, Concord NH, New York NY, Newark NJ
More records may be set through Tuesday. All part of the warm wave that heated up California a few days ago.
ralph ellis:
Well, I guess if you change what “these people” say then it becomes easy to attack the resulting strawman and actually think that you have said something relevant. The original phrase said, “Whether or not the sun has enough of an effect on climate…”
Look, the fact is that the W/m^2 change in forcing from the solar variations is considerably smaller than the forcing due to changes in CO2 levels. In order to make claims that changes in the sun are still the dominant factor in the climate over the last half century, it is necessary to posit some feedback mechanism such as cosmic rays that acts selectively only on the solar forcing. (It is apparently also necessary to ignore the fact that there has been no real trend in cosmic rays over the time when the warming has occurred.)
It is strange that the very same people who are so skeptical of positive feedbacks that act on all forcings equally are so willing to believe in positive feedbacks that act selectively on the forcing that they want to believe is most important.
[Actually, whether or not there is a detectable temperature effect due to the 11-year solar cycle comes down mainly to the issue of damping. I.e., the changes in forcing from min to max of the solar cycle is enough to cause a detectable change in temperature with our current estimates of climate sensitivity if it happens slowly enough…but it is not clear whether these changes are detectable once the damping effects associated with the frequency of these variations in factored in…and particularly when trying to separate this from other climate variability factors.]
OT but Catlin crew have come up with a new spin on the scientific ‘value’ of their jaunt.
The purpose of the Catlin Arctic Survey is for the Ice Team of Pen Hadow, Martin Hartley and Ann Daniels to gather data that will help scientists to assess how the ice is melting across the region where the expedition is drilling. In the planning stages, the team worked closely with scientists to ensure they would be gathering exactly the type of information required during their time on the ice. When the team returns in May, the role of the scientists will once again be in the ascendant. But for now, the skills that are needed are those of an experienced expedition team.
It’s a Brave New World indeed!
The Newspeak link
http://www.catlinarcticsurvey.com/headline.aspx?postId=173
ralph ellis (02:10:11) :
…No Sunspots recently
…(Note the media lies here. A lack of sunspot activity caused the 17th century mini Ice Age, however our latest minimum has nothing to do with climate, and it is all manmade CO2. I have never seen such global deceit in my entire life.)
The theory of Sunspot activity driving ALL climate change.
http://bourabai.narod.ru/landscheidt/new-e.htm
Global Temperature vs Sunspot activity
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1978/offset:-0.1/plot/pmod/from:1978/offset:-1365.25/scale:0.2
…
Isn’t this shooting yourself in the foot????
Let’s assume xxx is the cause of GW and TSI is another modulation on that temp rise.
LOW TSI (currently) = lower temperatures – apparently true at present but then this is not explaining the CONSTANT rise over the last 30 years which must be caused by xxx.
LOW TSI has in your eyes pulled the risen temperature down to near average temps.
In the next solar maximum, whenever that occurs say 5 years time, the reduction will be removed and we will be on a new high. So there will be a total of 15 years (10 years colling as you stated + 5 more for TSI to reach maximum) of TSI cooling. This is 15 years where xxx effect has been increasing. It’s going to be very HOT. We must find what xxx is!!!!!
You make the assertion that TI is THE cause of temperature variation. Why does this evident 11 year cycle not appear on FFT plots of temperature.
http://img22.imageshack.us/img22/5025/cetssnavgfft.jpg
You then use a plot to prove this. Even this does not show the effect – Temperature shows a sinusoidal component added to a positive linear trend. The TSI shows a sinusoidal component without the trend (fortuitously over thie period you chose the TSI sinusois and the temp sinusoid are similar frequencies.
Take a look at this plot comparing temperature vs SSN and Temperature vs CO2. Which do you think has the most significant effect on temperature?:
http://img99.imageshack.us/img99/2553/hadcrutvsco2andssn.jpg
GK (03:13:30) :
Are you saying TSI has variation from differnt sides of the Sun ? Surely not ?
Surely, yes. Imagine you have a huge sunspot on one side of the Sun. When that spot is facing us, TSI is smaller. When the spot is at 90 degrees [a quarter of a rotation] away from us we don’t see the spot, but we do see the enhanced brightness around the spot [called faculae] and so TSI is higher. So there is a distinct signature in TSI to the passage of a huge spot across the solar disk: first TSI goes up, then down, and finally [when the spot rotates out of view] up again.
On http://www.leif.org/research/TSI-SORCE-2008-now.png I have indicated the effect by an arrow pointing to a significant spot in 2008.23. The green sunspot curve was way up [relative to now, at least]. F10.7 sot up [the pink curve], but TSI had a deep minimum flanked by maxima. Since the magnetic field from that spot group takes a long time to disappear, TSI was enhanced every 27 days since then, giving rise to the 27-day recurrent peak in TSI. The amplitude of that peak has been slowly decreasing since. Around 2008.80 there was a [smaller] injection of new magnetic flux [see the green and pink curves] that has helped keeping the peak alive, but now it is clearly dying down.